From: "Jason A. Donenfeld" Jason@zx2c4.com

[ Upstream commit 5efcecd9a3b18078d3398b359a84c83f549e22cf ]

The clamp family of functions only makes sense if hi>=lo. If hi and lo are compile-time constants, then raise a build error. Doing so has already caught buggy code. This also introduces the infrastructure to improve the clamping function in subsequent commits.

[akpm@linux-foundation.org: coding-style cleanups] [akpm@linux-foundation.org: s@&&@&& @] Link: https://lkml.kernel.org/r/20220926133435.1333846-1-Jason@zx2c4.com Signed-off-by: Jason A. Donenfeld Jason@zx2c4.com Reviewed-by: Andy Shevchenko andriy.shevchenko@linux.intel.com Cc: Kees Cook keescook@chromium.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Eliav Farber farbere@amazon.com --- include/linux/minmax.h | 26 ++++++++++++++++++++++++-- 1 file changed, 24 insertions(+), 2 deletions(-)

diff --git a/include/linux/minmax.h b/include/linux/minmax.h index 1aea34b8f19b..8b092c66c5aa 100644 --- a/include/linux/minmax.h +++ b/include/linux/minmax.h @@ -37,6 +37,28 @@ __cmp(x, y, op), \ __cmp_once(x, y, __UNIQUE_ID(__x), __UNIQUE_ID(__y), op))

+#define __clamp(val, lo, hi) \ + __cmp(__cmp(val, lo, >), hi, <) + +#define __clamp_once(val, lo, hi, unique_val, unique_lo, unique_hi) ({ \ + typeof(val) unique_val = (val); \ + typeof(lo) unique_lo = (lo); \ + typeof(hi) unique_hi = (hi); \ + __clamp(unique_val, unique_lo, unique_hi); }) + +#define __clamp_input_check(lo, hi) \ + (BUILD_BUG_ON_ZERO(__builtin_choose_expr( \ + __is_constexpr((lo) > (hi)), (lo) > (hi), false))) + +#define __careful_clamp(val, lo, hi) ({ \ + __clamp_input_check(lo, hi) + \ + __builtin_choose_expr(__typecheck(val, lo) && __typecheck(val, hi) && \ + __typecheck(hi, lo) && __is_constexpr(val) && \ + __is_constexpr(lo) && __is_constexpr(hi), \ + __clamp(val, lo, hi), \ + __clamp_once(val, lo, hi, __UNIQUE_ID(__val), \ + __UNIQUE_ID(__lo), __UNIQUE_ID(__hi))); }) + /** * min - return minimum of two values of the same or compatible types * @x: first value @@ -103,7 +125,7 @@ * This macro does strict typechecking of @lo/@hi to make sure they are of the * same type as @val. See the unnecessary pointer comparisons. */ -#define clamp(val, lo, hi) min((typeof(val))max(val, lo), hi) +#define clamp(val, lo, hi) __careful_clamp(val, lo, hi)

/* * ..and if you can't take the strict @@ -138,7 +160,7 @@ * This macro does no typechecking and uses temporary variables of type * @type to make all the comparisons. */ -#define clamp_t(type, val, lo, hi) min_t(type, max_t(type, val, lo), hi) +#define clamp_t(type, val, lo, hi) __careful_clamp((type)(val), (type)(lo), (type)(hi))

/** * clamp_val - return a value clamped to a given range using val's type

From: "Matthew Wilcox (Oracle)" willy@infradead.org

[ Upstream commit f9bff0e31881d03badf191d3b0005839391f5f2b ]

Patch series "New page table range API", v6.

This patchset changes the API used by the MM to set up page table entries. The four APIs are:

set_ptes(mm, addr, ptep, pte, nr) update_mmu_cache_range(vma, addr, ptep, nr) flush_dcache_folio(folio) flush_icache_pages(vma, page, nr)

flush_dcache_folio() isn't technically new, but no architecture implemented it, so I've done that for them. The old APIs remain around but are mostly implemented by calling the new interfaces.

The new APIs are based around setting up N page table entries at once. The N entries belong to the same PMD, the same folio and the same VMA, so ptep++ is a legitimate operation, and locking is taken care of for you. Some architectures can do a better job of it than just a loop, but I have hesitated to make too deep a change to architectures I don't understand well.

One thing I have changed in every architecture is that PG_arch_1 is now a per-folio bit instead of a per-page bit when used for dcache clean/dirty tracking. This was something that would have to happen eventually, and it makes sense to do it now rather than iterate over every page involved in a cache flush and figure out if it needs to happen.

The point of all this is better performance, and Fengwei Yin has measured improvement on x86. I suspect you'll see improvement on your architecture too. Try the new will-it-scale test mentioned here: https://lore.kernel.org/linux-mm/20230206140639.538867-5-fengwei.yin@intel.c... You'll need to run it on an XFS filesystem and have CONFIG_TRANSPARENT_HUGEPAGE set.

This patchset is the basis for much of the anonymous large folio work being done by Ryan, so it's received quite a lot of testing over the last few months.

This patch (of 38):

Determine if a value lies within a range more efficiently (subtraction + comparison vs two comparisons and an AND). It also has useful (under some circumstances) behaviour if the range exceeds the maximum value of the type. Convert all the conflicting definitions of in_range() within the kernel; some can use the generic definition while others need their own definition.

Link: https://lkml.kernel.org/r/20230802151406.3735276-1-willy@infradead.org Link: https://lkml.kernel.org/r/20230802151406.3735276-2-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) willy@infradead.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Eliav Farber farbere@amazon.com --- arch/arm/mm/pageattr.c | 6 ++--- .../drm/arm/display/include/malidp_utils.h | 2 +- .../display/komeda/komeda_pipeline_state.c | 24 ++++++++--------- drivers/gpu/drm/msm/adreno/a6xx_gmu.c | 6 ----- .../net/ethernet/chelsio/cxgb3/cxgb3_main.c | 18 ++++++------- fs/btrfs/misc.h | 2 -- fs/ext2/balloc.c | 2 -- fs/ext4/ext4.h | 2 -- fs/ufs/util.h | 6 ----- include/linux/minmax.h | 27 +++++++++++++++++++ lib/logic_pio.c | 3 --- net/netfilter/nf_nat_core.c | 6 ++--- net/tipc/core.h | 2 +- net/tipc/link.c | 10 +++---- 14 files changed, 61 insertions(+), 55 deletions(-)

diff --git a/arch/arm/mm/pageattr.c b/arch/arm/mm/pageattr.c index 9790ae3a8c68..3b3bfa825fad 100644 --- a/arch/arm/mm/pageattr.c +++ b/arch/arm/mm/pageattr.c @@ -25,7 +25,7 @@ static int change_page_range(pte_t *ptep, unsigned long addr, void *data) return 0; }

-static bool in_range(unsigned long start, unsigned long size, +static bool range_in_range(unsigned long start, unsigned long size, unsigned long range_start, unsigned long range_end) { return start >= range_start && start < range_end && @@ -46,8 +46,8 @@ static int change_memory_common(unsigned long addr, int numpages, if (!size) return 0;

- if (!in_range(start, size, MODULES_VADDR, MODULES_END) && - !in_range(start, size, VMALLOC_START, VMALLOC_END)) + if (!range_in_range(start, size, MODULES_VADDR, MODULES_END) && + !range_in_range(start, size, VMALLOC_START, VMALLOC_END)) return -EINVAL;

data.set_mask = set_mask; diff --git a/drivers/gpu/drm/arm/display/include/malidp_utils.h b/drivers/gpu/drm/arm/display/include/malidp_utils.h index 49a1d7f3539c..9f83baac6ed8 100644 --- a/drivers/gpu/drm/arm/display/include/malidp_utils.h +++ b/drivers/gpu/drm/arm/display/include/malidp_utils.h @@ -35,7 +35,7 @@ static inline void set_range(struct malidp_range *rg, u32 start, u32 end) rg->end = end; }

-static inline bool in_range(struct malidp_range *rg, u32 v) +static inline bool malidp_in_range(struct malidp_range *rg, u32 v) { return (v >= rg->start) && (v <= rg->end); } diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_pipeline_state.c b/drivers/gpu/drm/arm/display/komeda/komeda_pipeline_state.c index 7cc891c091f8..3e414d2fbdda 100644 --- a/drivers/gpu/drm/arm/display/komeda/komeda_pipeline_state.c +++ b/drivers/gpu/drm/arm/display/komeda/komeda_pipeline_state.c @@ -305,12 +305,12 @@ komeda_layer_check_cfg(struct komeda_layer *layer, if (komeda_fb_check_src_coords(kfb, src_x, src_y, src_w, src_h)) return -EINVAL;

- if (!in_range(&layer->hsize_in, src_w)) { + if (!malidp_in_range(&layer->hsize_in, src_w)) { DRM_DEBUG_ATOMIC("invalidate src_w %d.\n", src_w); return -EINVAL; }

- if (!in_range(&layer->vsize_in, src_h)) { + if (!malidp_in_range(&layer->vsize_in, src_h)) { DRM_DEBUG_ATOMIC("invalidate src_h %d.\n", src_h); return -EINVAL; } @@ -452,14 +452,14 @@ komeda_scaler_check_cfg(struct komeda_scaler *scaler, hsize_out = dflow->out_w; vsize_out = dflow->out_h;

- if (!in_range(&scaler->hsize, hsize_in) || - !in_range(&scaler->hsize, hsize_out)) { + if (!malidp_in_range(&scaler->hsize, hsize_in) || + !malidp_in_range(&scaler->hsize, hsize_out)) { DRM_DEBUG_ATOMIC("Invalid horizontal sizes"); return -EINVAL; }

- if (!in_range(&scaler->vsize, vsize_in) || - !in_range(&scaler->vsize, vsize_out)) { + if (!malidp_in_range(&scaler->vsize, vsize_in) || + !malidp_in_range(&scaler->vsize, vsize_out)) { DRM_DEBUG_ATOMIC("Invalid vertical sizes"); return -EINVAL; } @@ -574,13 +574,13 @@ komeda_splitter_validate(struct komeda_splitter *splitter, return -EINVAL; }

- if (!in_range(&splitter->hsize, dflow->in_w)) { + if (!malidp_in_range(&splitter->hsize, dflow->in_w)) { DRM_DEBUG_ATOMIC("split in_w:%d is out of the acceptable range.\n", dflow->in_w); return -EINVAL; }

- if (!in_range(&splitter->vsize, dflow->in_h)) { + if (!malidp_in_range(&splitter->vsize, dflow->in_h)) { DRM_DEBUG_ATOMIC("split in_h: %d exceeds the acceptable range.\n", dflow->in_h); return -EINVAL; @@ -624,13 +624,13 @@ komeda_merger_validate(struct komeda_merger *merger, return -EINVAL; }

- if (!in_range(&merger->hsize_merged, output->out_w)) { + if (!malidp_in_range(&merger->hsize_merged, output->out_w)) { DRM_DEBUG_ATOMIC("merged_w: %d is out of the accepted range.\n", output->out_w); return -EINVAL; }

- if (!in_range(&merger->vsize_merged, output->out_h)) { + if (!malidp_in_range(&merger->vsize_merged, output->out_h)) { DRM_DEBUG_ATOMIC("merged_h: %d is out of the accepted range.\n", output->out_h); return -EINVAL; @@ -866,8 +866,8 @@ void komeda_complete_data_flow_cfg(struct komeda_layer *layer, * input/output range. */ if (dflow->en_scaling && scaler) - dflow->en_split = !in_range(&scaler->hsize, dflow->in_w) || - !in_range(&scaler->hsize, dflow->out_w); + dflow->en_split = !malidp_in_range(&scaler->hsize, dflow->in_w) || + !malidp_in_range(&scaler->hsize, dflow->out_w); }

static bool merger_is_available(struct komeda_pipeline *pipe, diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c index 655938df4531..f11da95566da 100644 --- a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c +++ b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c @@ -657,12 +657,6 @@ struct block_header { u32 data[]; };

-/* this should be a general kernel helper */ -static int in_range(u32 addr, u32 start, u32 size) -{ - return addr >= start && addr < start + size; -} - static bool fw_block_mem(struct a6xx_gmu_bo *bo, const struct block_header *blk) { if (!in_range(blk->addr, bo->iova, bo->size)) diff --git a/drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c b/drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c index 8a167eea288c..10790a370f22 100644 --- a/drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c +++ b/drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c @@ -2131,7 +2131,7 @@ static const struct ethtool_ops cxgb_ethtool_ops = { .set_link_ksettings = set_link_ksettings, };

-static int in_range(int val, int lo, int hi) +static int cxgb_in_range(int val, int lo, int hi) { return val < 0 || (val <= hi && val >= lo); } @@ -2162,19 +2162,19 @@ static int cxgb_extension_ioctl(struct net_device *dev, void __user *useraddr) return -EINVAL; if (t.qset_idx >= SGE_QSETS) return -EINVAL; - if (!in_range(t.intr_lat, 0, M_NEWTIMER) || - !in_range(t.cong_thres, 0, 255) || - !in_range(t.txq_size[0], MIN_TXQ_ENTRIES, + if (!cxgb_in_range(t.intr_lat, 0, M_NEWTIMER) || + !cxgb_in_range(t.cong_thres, 0, 255) || + !cxgb_in_range(t.txq_size[0], MIN_TXQ_ENTRIES, MAX_TXQ_ENTRIES) || - !in_range(t.txq_size[1], MIN_TXQ_ENTRIES, + !cxgb_in_range(t.txq_size[1], MIN_TXQ_ENTRIES, MAX_TXQ_ENTRIES) || - !in_range(t.txq_size[2], MIN_CTRL_TXQ_ENTRIES, + !cxgb_in_range(t.txq_size[2], MIN_CTRL_TXQ_ENTRIES, MAX_CTRL_TXQ_ENTRIES) || - !in_range(t.fl_size[0], MIN_FL_ENTRIES, + !cxgb_in_range(t.fl_size[0], MIN_FL_ENTRIES, MAX_RX_BUFFERS) || - !in_range(t.fl_size[1], MIN_FL_ENTRIES, + !cxgb_in_range(t.fl_size[1], MIN_FL_ENTRIES, MAX_RX_JUMBO_BUFFERS) || - !in_range(t.rspq_size, MIN_RSPQ_ENTRIES, + !cxgb_in_range(t.rspq_size, MIN_RSPQ_ENTRIES, MAX_RSPQ_ENTRIES)) return -EINVAL;

diff --git a/fs/btrfs/misc.h b/fs/btrfs/misc.h index 6461ebc3a1c1..40ad75511435 100644 --- a/fs/btrfs/misc.h +++ b/fs/btrfs/misc.h @@ -8,8 +8,6 @@ #include <asm/div64.h> #include <linux/rbtree.h>

-#define in_range(b, first, len) ((b) >= (first) && (b) < (first) + (len)) - static inline void cond_wake_up(struct wait_queue_head *wq) { /* diff --git a/fs/ext2/balloc.c b/fs/ext2/balloc.c index 9bf086821eb3..1d9380c5523b 100644 --- a/fs/ext2/balloc.c +++ b/fs/ext2/balloc.c @@ -36,8 +36,6 @@ */

-#define in_range(b, first, len) ((b) >= (first) && (b) <= (first) + (len) - 1) - struct ext2_group_desc * ext2_get_group_desc(struct super_block * sb, unsigned int block_group, struct buffer_head ** bh) diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 1dc1292d8977..4adaf97d7435 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -3659,8 +3659,6 @@ static inline void set_bitmap_uptodate(struct buffer_head *bh) set_bit(BH_BITMAP_UPTODATE, &(bh)->b_state); }

-#define in_range(b, first, len) ((b) >= (first) && (b) <= (first) + (len) - 1) - /* For ioend & aio unwritten conversion wait queues */ #define EXT4_WQ_HASH_SZ 37 #define ext4_ioend_wq(v) (&ext4__ioend_wq[((unsigned long)(v)) %\ diff --git a/fs/ufs/util.h b/fs/ufs/util.h index 4931bec1a01c..89247193d96d 100644 --- a/fs/ufs/util.h +++ b/fs/ufs/util.h @@ -11,12 +11,6 @@ #include <linux/fs.h> #include "swab.h"

- -/* - * some useful macros - */ -#define in_range(b,first,len) ((b)>=(first)&&(b)<(first)+(len)) - /* * functions used for retyping */ diff --git a/include/linux/minmax.h b/include/linux/minmax.h index abdeae409dad..7affadcb2a29 100644 --- a/include/linux/minmax.h +++ b/include/linux/minmax.h @@ -3,6 +3,7 @@ #define _LINUX_MINMAX_H

#include <linux/const.h> +#include <linux/types.h>

/* * min()/max()/clamp() macros must accomplish three things: @@ -175,6 +176,32 @@ */ #define clamp_val(val, lo, hi) clamp_t(typeof(val), val, lo, hi)

+static inline bool in_range64(u64 val, u64 start, u64 len) +{ + return (val - start) < len; +} + +static inline bool in_range32(u32 val, u32 start, u32 len) +{ + return (val - start) < len; +} + +/** + * in_range - Determine if a value lies within a range. + * @val: Value to test. + * @start: First value in range. + * @len: Number of values in range. + * + * This is more efficient than "if (start <= val && val < (start + len))". + * It also gives a different answer if @start + @len overflows the size of + * the type by a sufficient amount to encompass @val. Decide for yourself + * which behaviour you want, or prove that start + len never overflow. + * Do not blindly replace one form with the other. + */ +#define in_range(val, start, len) \ + ((sizeof(start) | sizeof(len) | sizeof(val)) <= sizeof(u32) ? \ + in_range32(val, start, len) : in_range64(val, start, len)) + /** * swap - swap values of @a and @b * @a: first value diff --git a/lib/logic_pio.c b/lib/logic_pio.c index 07b4b9a1f54b..2ea564a40064 100644 --- a/lib/logic_pio.c +++ b/lib/logic_pio.c @@ -20,9 +20,6 @@ static LIST_HEAD(io_range_list); static DEFINE_MUTEX(io_range_mutex);

-/* Consider a kernel general helper for this */ -#define in_range(b, first, len) ((b) >= (first) && (b) < (first) + (len)) - /** * logic_pio_register_range - register logical PIO range for a host * @new_range: pointer to the IO range to be registered. diff --git a/net/netfilter/nf_nat_core.c b/net/netfilter/nf_nat_core.c index b7c3c902290f..96b61f0658c8 100644 --- a/net/netfilter/nf_nat_core.c +++ b/net/netfilter/nf_nat_core.c @@ -262,7 +262,7 @@ static bool l4proto_in_range(const struct nf_conntrack_tuple *tuple, /* If we source map this tuple so reply looks like reply_tuple, will * that meet the constraints of range. */ -static int in_range(const struct nf_conntrack_tuple *tuple, +static int nf_in_range(const struct nf_conntrack_tuple *tuple, const struct nf_nat_range2 *range) { /* If we are supposed to map IPs, then we must be in the @@ -311,7 +311,7 @@ find_appropriate_src(struct net *net, &ct->tuplehash[IP_CT_DIR_REPLY].tuple); result->dst = tuple->dst;

- if (in_range(result, range)) + if (nf_in_range(result, range)) return 1; } } @@ -543,7 +543,7 @@ get_unique_tuple(struct nf_conntrack_tuple *tuple, if (maniptype == NF_NAT_MANIP_SRC && !(range->flags & NF_NAT_RANGE_PROTO_RANDOM_ALL)) { /* try the original tuple first */ - if (in_range(orig_tuple, range)) { + if (nf_in_range(orig_tuple, range)) { if (!nf_nat_used_tuple(orig_tuple, ct)) { *tuple = *orig_tuple; return; diff --git a/net/tipc/core.h b/net/tipc/core.h index 73a26b0b9ca1..7c86fa4bb967 100644 --- a/net/tipc/core.h +++ b/net/tipc/core.h @@ -199,7 +199,7 @@ static inline int less(u16 left, u16 right) return less_eq(left, right) && (mod(right) != mod(left)); }

-static inline int in_range(u16 val, u16 min, u16 max) +static inline int tipc_in_range(u16 val, u16 min, u16 max) { return !less(val, min) && !more(val, max); } diff --git a/net/tipc/link.c b/net/tipc/link.c index 336d1bb2cf6a..ca96bdb77190 100644 --- a/net/tipc/link.c +++ b/net/tipc/link.c @@ -1588,7 +1588,7 @@ static int tipc_link_advance_transmq(struct tipc_link *l, struct tipc_link *r, last_ga->bgack_cnt); } /* Check against the last Gap ACK block */ - if (in_range(seqno, start, end)) + if (tipc_in_range(seqno, start, end)) continue; /* Update/release the packet peer is acking */ bc_has_acked = true; @@ -2216,12 +2216,12 @@ static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb, strncpy(if_name, data, TIPC_MAX_IF_NAME);

/* Update own tolerance if peer indicates a non-zero value */ - if (in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL)) { + if (tipc_in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL)) { l->tolerance = peers_tol; l->bc_rcvlink->tolerance = peers_tol; } /* Update own priority if peer's priority is higher */ - if (in_range(peers_prio, l->priority + 1, TIPC_MAX_LINK_PRI)) + if (tipc_in_range(peers_prio, l->priority + 1, TIPC_MAX_LINK_PRI)) l->priority = peers_prio;

/* If peer is going down we want full re-establish cycle */ @@ -2264,13 +2264,13 @@ static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb, l->rcv_nxt_state = msg_seqno(hdr) + 1;

/* Update own tolerance if peer indicates a non-zero value */ - if (in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL)) { + if (tipc_in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL)) { l->tolerance = peers_tol; l->bc_rcvlink->tolerance = peers_tol; } /* Update own prio if peer indicates a different value */ if ((peers_prio != l->priority) && - in_range(peers_prio, 1, TIPC_MAX_LINK_PRI)) { + tipc_in_range(peers_prio, 1, TIPC_MAX_LINK_PRI)) { l->priority = peers_prio; rc = tipc_link_fsm_evt(l, LINK_FAILURE_EVT); }

From: Andy Shevchenko andriy.shevchenko@linux.intel.com

[ Upstream commit 5e57418a2031cd5e1863efdf3d7447a16a368172 ]

It appears that compiler_types.h already have an implementation of the __unconst_integer_typeof() called __unqual_scalar_typeof(). Use it instead of the copy.

Link: https://lkml.kernel.org/r/20230911154913.4176033-1-andriy.shevchenko@linux.i... Signed-off-by: Andy Shevchenko andriy.shevchenko@linux.intel.com Acked-by: Herve Codina herve.codina@bootlin.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Eliav Farber farbere@amazon.com --- include/linux/minmax.h | 26 +++----------------------- 1 file changed, 3 insertions(+), 23 deletions(-)

diff --git a/include/linux/minmax.h b/include/linux/minmax.h index 0e89c78810f6..c813c1187510 100644 --- a/include/linux/minmax.h +++ b/include/linux/minmax.h @@ -2,6 +2,7 @@ #ifndef _LINUX_MINMAX_H #define _LINUX_MINMAX_H

+#include <linux/compiler_types.h> #include <linux/const.h> #include <linux/types.h>

@@ -151,27 +152,6 @@ */ #define max_t(type, x, y) __careful_cmp((type)(x), (type)(y), >)

-/* - * Remove a const qualifier from integer types - * _Generic(foo, type-name: association, ..., default: association) performs a - * comparison against the foo type (not the qualified type). - * Do not use the const keyword in the type-name as it will not match the - * unqualified type of foo. - */ -#define __unconst_integer_type_cases(type) \ - unsigned type: (unsigned type)0, \ - signed type: (signed type)0 - -#define __unconst_integer_typeof(x) typeof( \ - _Generic((x), \ - char: (char)0, \ - __unconst_integer_type_cases(char), \ - __unconst_integer_type_cases(short), \ - __unconst_integer_type_cases(int), \ - __unconst_integer_type_cases(long), \ - __unconst_integer_type_cases(long long), \ - default: (x))) - /* * Do not check the array parameter using __must_be_array(). * In the following legit use-case where the "array" passed is a simple pointer, @@ -186,13 +166,13 @@ * 'int *buff' and 'int buff[N]' types. * * The array can be an array of const items. - * typeof() keeps the const qualifier. Use __unconst_integer_typeof() in order + * typeof() keeps the const qualifier. Use __unqual_scalar_typeof() in order * to discard the const qualifier for the __element variable. */ #define __minmax_array(op, array, len) ({ \ typeof(&(array)[0]) __array = (array); \ typeof(len) __len = (len); \ - __unconst_integer_typeof(__array[0]) __element = __array[--__len]; \ + __unqual_scalar_typeof(__array[0]) __element = __array[--__len];\ while (__len--) \ __element = op(__element, __array[__len]); \ __element; })

From: David Laight David.Laight@ACULAB.COM

[ Upstream commit d03eba99f5bf7cbc6e2fdde3b6fa36954ad58e09 ]

The type-check in min()/max() is there to stop unexpected results if a negative value gets converted to a large unsigned value. However it also rejects 'unsigned int' v 'unsigned long' compares which are common and never problematc.

Replace the 'same type' check with a 'same signedness' check.

The new test isn't itself a compile time error, so use static_assert() to report the error and give a meaningful error message.

Due to the way builtin_choose_expr() works detecting the error in the 'non-constant' side (where static_assert() can be used) also detects errors when the arguments are constant.

Link: https://lkml.kernel.org/r/fe7e6c542e094bfca655abcd323c1c98@AcuMS.aculab.com Signed-off-by: David Laight david.laight@aculab.com Cc: Andy Shevchenko andriy.shevchenko@linux.intel.com Cc: Christoph Hellwig hch@infradead.org Cc: Jason A. Donenfeld Jason@zx2c4.com Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Matthew Wilcox (Oracle) willy@infradead.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Eliav Farber farbere@amazon.com --- include/linux/minmax.h | 60 ++++++++++++++++++++++-------------------- 1 file changed, 32 insertions(+), 28 deletions(-)

diff --git a/include/linux/minmax.h b/include/linux/minmax.h index 2a197f54fe05..8718fd71a793 100644 --- a/include/linux/minmax.h +++ b/include/linux/minmax.h @@ -12,9 +12,8 @@ * * - avoid multiple evaluations of the arguments (so side-effects like * "x++" happen only once) when non-constant. - * - perform strict type-checking (to generate warnings instead of - * nasty runtime surprises). See the "unnecessary" pointer comparison - * in __typecheck(). + * - perform signed v unsigned type-checking (to generate compile + * errors instead of nasty runtime surprises). * - retain result as a constant expressions when called with only * constant expressions (to avoid tripping VLA warnings in stack * allocation usage). @@ -22,23 +21,30 @@ #define __typecheck(x, y) \ (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))

-#define __no_side_effects(x, y) \ - (__is_constexpr(x) && __is_constexpr(y)) +/* is_signed_type() isn't a constexpr for pointer types */ +#define __is_signed(x) \ + __builtin_choose_expr(__is_constexpr(is_signed_type(typeof(x))), \ + is_signed_type(typeof(x)), 0)

-#define __safe_cmp(x, y) \ - (__typecheck(x, y) && __no_side_effects(x, y)) +#define __types_ok(x, y) \ + (__is_signed(x) == __is_signed(y))

-#define __cmp(x, y, op) ((x) op (y) ? (x) : (y)) +#define __cmp_op_min < +#define __cmp_op_max >

-#define __cmp_once(x, y, unique_x, unique_y, op) ({ \ +#define __cmp(op, x, y) ((x) __cmp_op_##op (y) ? (x) : (y)) + +#define __cmp_once(op, x, y, unique_x, unique_y) ({ \ typeof(x) unique_x = (x); \ typeof(y) unique_y = (y); \ - __cmp(unique_x, unique_y, op); }) + static_assert(__types_ok(x, y), \ + #op "(" #x ", " #y ") signedness error, fix types or consider u" #op "() before " #op "_t()"); \ + __cmp(op, unique_x, unique_y); })

-#define __careful_cmp(x, y, op) \ - __builtin_choose_expr(__safe_cmp(x, y), \ - __cmp(x, y, op), \ - __cmp_once(x, y, __UNIQUE_ID(__x), __UNIQUE_ID(__y), op)) +#define __careful_cmp(op, x, y) \ + __builtin_choose_expr(__is_constexpr((x) - (y)), \ + __cmp(op, x, y), \ + __cmp_once(op, x, y, __UNIQUE_ID(__x), __UNIQUE_ID(__y)))

#define __clamp(val, lo, hi) \ ((val) >= (hi) ? (hi) : ((val) <= (lo) ? (lo) : (val))) @@ -47,17 +53,15 @@ typeof(val) unique_val = (val); \ typeof(lo) unique_lo = (lo); \ typeof(hi) unique_hi = (hi); \ + static_assert(__builtin_choose_expr(__is_constexpr((lo) > (hi)), \ + (lo) <= (hi), true), \ + "clamp() low limit " #lo " greater than high limit " #hi); \ + static_assert(__types_ok(val, lo), "clamp() 'lo' signedness error"); \ + static_assert(__types_ok(val, hi), "clamp() 'hi' signedness error"); \ __clamp(unique_val, unique_lo, unique_hi); })

-#define __clamp_input_check(lo, hi) \ - (BUILD_BUG_ON_ZERO(__builtin_choose_expr( \ - __is_constexpr((lo) > (hi)), (lo) > (hi), false))) - #define __careful_clamp(val, lo, hi) ({ \ - __clamp_input_check(lo, hi) + \ - __builtin_choose_expr(__typecheck(val, lo) && __typecheck(val, hi) && \ - __typecheck(hi, lo) && __is_constexpr(val) && \ - __is_constexpr(lo) && __is_constexpr(hi), \ + __builtin_choose_expr(__is_constexpr((val) - (lo) + (hi)), \ __clamp(val, lo, hi), \ __clamp_once(val, lo, hi, __UNIQUE_ID(__val), \ __UNIQUE_ID(__lo), __UNIQUE_ID(__hi))); }) @@ -67,14 +71,14 @@ * @x: first value * @y: second value */ -#define min(x, y) __careful_cmp(x, y, <) +#define min(x, y) __careful_cmp(min, x, y)

/** * max - return maximum of two values of the same or compatible types * @x: first value * @y: second value */ -#define max(x, y) __careful_cmp(x, y, >) +#define max(x, y) __careful_cmp(max, x, y)

/** * umin - return minimum of two non-negative values @@ -83,7 +87,7 @@ * @y: second value */ #define umin(x, y) \ - __careful_cmp((x) + 0u + 0ul + 0ull, (y) + 0u + 0ul + 0ull, <) + __careful_cmp(min, (x) + 0u + 0ul + 0ull, (y) + 0u + 0ul + 0ull)

/** * umax - return maximum of two non-negative values @@ -91,7 +95,7 @@ * @y: second value */ #define umax(x, y) \ - __careful_cmp((x) + 0u + 0ul + 0ull, (y) + 0u + 0ul + 0ull, >) + __careful_cmp(max, (x) + 0u + 0ul + 0ull, (y) + 0u + 0ul + 0ull)

/** * min3 - return minimum of three values @@ -143,7 +147,7 @@ * @x: first value * @y: second value */ -#define min_t(type, x, y) __careful_cmp((type)(x), (type)(y), <) +#define min_t(type, x, y) __careful_cmp(min, (type)(x), (type)(y))

/** * max_t - return maximum of two values, using the specified type @@ -151,7 +155,7 @@ * @x: first value * @y: second value */ -#define max_t(type, x, y) __careful_cmp((type)(x), (type)(y), >) +#define max_t(type, x, y) __careful_cmp(max, (type)(x), (type)(y))

/* * Do not check the array parameter using __must_be_array().

From: David Laight David.Laight@ACULAB.COM

[ Upstream commit 4ead534fba42fc4fd41163297528d2aa731cd121 ]

Since 'unsigned char/short' get promoted to 'signed int' it is safe to compare them against an 'int' value.

Link: https://lkml.kernel.org/r/8732ef5f809c47c28a7be47c938b28d4@AcuMS.aculab.com Signed-off-by: David Laight david.laight@aculab.com Cc: Andy Shevchenko andriy.shevchenko@linux.intel.com Cc: Christoph Hellwig hch@infradead.org Cc: Jason A. Donenfeld Jason@zx2c4.com Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Matthew Wilcox (Oracle) willy@infradead.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Eliav Farber farbere@amazon.com --- include/linux/minmax.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/include/linux/minmax.h b/include/linux/minmax.h index c0e738eacefa..842c1db62ffe 100644 --- a/include/linux/minmax.h +++ b/include/linux/minmax.h @@ -26,8 +26,9 @@ __builtin_choose_expr(__is_constexpr(is_signed_type(typeof(x))), \ is_signed_type(typeof(x)), 0)

-#define __types_ok(x, y) \ - (__is_signed(x) == __is_signed(y)) +#define __types_ok(x, y) \ + (__is_signed(x) == __is_signed(y) || \ + __is_signed((x) + 0) == __is_signed((y) + 0))

#define __cmp_op_min < #define __cmp_op_max >

From: Linus Torvalds torvalds@linux-foundation.org

[ Upstream commit 3a7e02c040b130b5545e4b115aada7bacd80a2b6 ]

The minmax infrastructure is overkill for simple constants, and can cause huge expansions because those simple constants are then used by other things.

For example, 'pageblock_order' is a core VM constant, but because it was implemented using 'min_t()' and all the type-checking that involves, it actually expanded to something like 2.5kB of preprocessor noise.

And when that simple constant was then used inside other expansions:

#define pageblock_nr_pages (1UL << pageblock_order) #define pageblock_start_pfn(pfn) ALIGN_DOWN((pfn), pageblock_nr_pages)

and we then use that inside a 'max()' macro:

case ISOLATE_SUCCESS: update_cached = false; last_migrated_pfn = max(cc->zone->zone_start_pfn, pageblock_start_pfn(cc->migrate_pfn - 1));

the end result was that one statement expanding to 253kB in size.

There are probably other cases of this, but this one case certainly stood out.

I've added 'MIN_T()' and 'MAX_T()' macros for this kind of "core simple constant with specific type" use. These macros skip the type checking, and as such need to be very sparingly used only for obvious cases that have active issues like this.

Reported-by: Lorenzo Stoakes lorenzo.stoakes@oracle.com Link: https://lore.kernel.org/all/36aa2cad-1db1-4abf-8dd2-fb20484aabc3@lucifer.loc... Cc: David Laight David.Laight@aculab.com Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Eliav Farber farbere@amazon.com --- include/linux/minmax.h | 7 +++++++ 1 file changed, 7 insertions(+)

diff --git a/include/linux/minmax.h b/include/linux/minmax.h index 2ec559284a9f..a7ef65f78933 100644 --- a/include/linux/minmax.h +++ b/include/linux/minmax.h @@ -270,4 +270,11 @@ static inline bool in_range32(u32 val, u32 start, u32 len) #define swap(a, b) \ do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)

+/* + * Use these carefully: no type checking, and uses the arguments + * multiple times. Use for obvious constants only. + */ +#define MIN_T(type,a,b) __cmp(min,(type)(a),(type)(b)) +#define MAX_T(type,a,b) __cmp(max,(type)(a),(type)(b)) + #endif /* _LINUX_MINMAX_H */

From: Linus Torvalds torvalds@linux-foundation.org

[ Upstream commit 017fa3e89187848fd056af757769c9e66ac3e93d ]

This simplifies the min_t() and max_t() macros by no longer making them work in the context of a C constant expression.

That means that you can no longer use them for static initializers or for array sizes in type definitions, but there were only a couple of such uses, and all of them were converted (famous last words) to use MIN_T/MAX_T instead.

Cc: David Laight David.Laight@aculab.com Cc: Lorenzo Stoakes lorenzo.stoakes@oracle.com Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Eliav Farber farbere@amazon.com --- include/linux/minmax.h | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/include/linux/minmax.h b/include/linux/minmax.h index a7ef65f78933..9c2848abc804 100644 --- a/include/linux/minmax.h +++ b/include/linux/minmax.h @@ -45,17 +45,20 @@

#define __cmp(op, x, y) ((x) __cmp_op_##op (y) ? (x) : (y))

-#define __cmp_once(op, x, y, unique_x, unique_y) ({ \ - typeof(x) unique_x = (x); \ - typeof(y) unique_y = (y); \ +#define __cmp_once_unique(op, type, x, y, ux, uy) \ + ({ type ux = (x); type uy = (y); __cmp(op, ux, uy); }) + +#define __cmp_once(op, type, x, y) \ + __cmp_once_unique(op, type, x, y, __UNIQUE_ID(x_), __UNIQUE_ID(y_)) + +#define __careful_cmp_once(op, x, y) ({ \ static_assert(__types_ok(x, y), \ #op "(" #x ", " #y ") signedness error, fix types or consider u" #op "() before " #op "_t()"); \ - __cmp(op, unique_x, unique_y); }) + __cmp_once(op, __auto_type, x, y); })

#define __careful_cmp(op, x, y) \ __builtin_choose_expr(__is_constexpr((x) - (y)), \ - __cmp(op, x, y), \ - __cmp_once(op, x, y, __UNIQUE_ID(__x), __UNIQUE_ID(__y))) + __cmp(op, x, y), __careful_cmp_once(op, x, y))

#define __clamp(val, lo, hi) \ ((val) >= (hi) ? (hi) : ((val) <= (lo) ? (lo) : (val))) @@ -158,7 +161,7 @@ * @x: first value * @y: second value */ -#define min_t(type, x, y) __careful_cmp(min, (type)(x), (type)(y)) +#define min_t(type, x, y) __cmp_once(min, type, x, y)

/** * max_t - return maximum of two values, using the specified type @@ -166,7 +169,7 @@ * @x: first value * @y: second value */ -#define max_t(type, x, y) __careful_cmp(max, (type)(x), (type)(y)) +#define max_t(type, x, y) __cmp_once(max, type, x, y)

/* * Do not check the array parameter using __must_be_array().

From: Linus Torvalds torvalds@linux-foundation.org

[ Upstream commit cb04e8b1d2f24c4c2c92f7b7529031fc35a16fed ]

We only had a couple of array[] declarations, and changing them to just use 'MAX()' instead of 'max()' fixes the issue.

This will allow us to simplify our min/max macros enormously, since they can now unconditionally use temporary variables to avoid using the argument values multiple times.

Cc: David Laight David.Laight@aculab.com Cc: Lorenzo Stoakes lorenzo.stoakes@oracle.com Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Eliav Farber farbere@amazon.com --- drivers/input/touchscreen/cyttsp4_core.c | 2 +- drivers/md/dm-integrity.c | 4 ++-- fs/btrfs/tree-checker.c | 2 +- lib/vsprintf.c | 2 +- 4 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/input/touchscreen/cyttsp4_core.c b/drivers/input/touchscreen/cyttsp4_core.c index 02a73d9a4def..c10140c9aafa 100644 --- a/drivers/input/touchscreen/cyttsp4_core.c +++ b/drivers/input/touchscreen/cyttsp4_core.c @@ -857,7 +857,7 @@ static void cyttsp4_get_mt_touches(struct cyttsp4_mt_data *md, int num_cur_tch) struct cyttsp4_touch tch; int sig; int i, j, t = 0; - int ids[max(CY_TMA1036_MAX_TCH, CY_TMA4XX_MAX_TCH)]; + int ids[MAX(CY_TMA1036_MAX_TCH, CY_TMA4XX_MAX_TCH)];

memset(ids, 0, si->si_ofs.tch_abs[CY_TCH_T].max * sizeof(int)); for (i = 0; i < num_cur_tch; i++) { diff --git a/drivers/md/dm-integrity.c b/drivers/md/dm-integrity.c index 7fa3bf74747d..917ba18be77f 100644 --- a/drivers/md/dm-integrity.c +++ b/drivers/md/dm-integrity.c @@ -1600,7 +1600,7 @@ static void integrity_metadata(struct work_struct *w) struct bio *bio = dm_bio_from_per_bio_data(dio, sizeof(struct dm_integrity_io)); char *checksums; unsigned extra_space = unlikely(digest_size > ic->tag_size) ? digest_size - ic->tag_size : 0; - char checksums_onstack[max((size_t)HASH_MAX_DIGESTSIZE, MAX_TAG_SIZE)]; + char checksums_onstack[MAX(HASH_MAX_DIGESTSIZE, MAX_TAG_SIZE)]; sector_t sector; unsigned sectors_to_process;

@@ -1882,7 +1882,7 @@ static bool __journal_read_write(struct dm_integrity_io *dio, struct bio *bio, } while (++s < ic->sectors_per_block); #ifdef INTERNAL_VERIFY if (ic->internal_hash) { - char checksums_onstack[max((size_t)HASH_MAX_DIGESTSIZE, MAX_TAG_SIZE)]; + char checksums_onstack[MAX(HASH_MAX_DIGESTSIZE, MAX_TAG_SIZE)];

integrity_sector_checksum(ic, logical_sector, mem + bv.bv_offset, checksums_onstack); if (unlikely(memcmp(checksums_onstack, journal_entry_tag(ic, je), ic->tag_size))) { diff --git a/fs/btrfs/tree-checker.c b/fs/btrfs/tree-checker.c index c28bb37688c6..fd4768c5e439 100644 --- a/fs/btrfs/tree-checker.c +++ b/fs/btrfs/tree-checker.c @@ -587,7 +587,7 @@ static int check_dir_item(struct extent_buffer *leaf, */ if (key->type == BTRFS_DIR_ITEM_KEY || key->type == BTRFS_XATTR_ITEM_KEY) { - char namebuf[max(BTRFS_NAME_LEN, XATTR_NAME_MAX)]; + char namebuf[MAX(BTRFS_NAME_LEN, XATTR_NAME_MAX)];

read_extent_buffer(leaf, namebuf, (unsigned long)(di + 1), name_len); diff --git a/lib/vsprintf.c b/lib/vsprintf.c index b08b8ee1bbc0..90372391ce90 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -1078,7 +1078,7 @@ char *resource_string(char *buf, char *end, struct resource *res, #define FLAG_BUF_SIZE (2 * sizeof(res->flags)) #define DECODED_BUF_SIZE sizeof("[mem - 64bit pref window disabled]") #define RAW_BUF_SIZE sizeof("[mem - flags 0x]") - char sym[max(2*RSRC_BUF_SIZE + DECODED_BUF_SIZE, + char sym[MAX(2*RSRC_BUF_SIZE + DECODED_BUF_SIZE, 2*RSRC_BUF_SIZE + FLAG_BUF_SIZE + RAW_BUF_SIZE)];

char *p = sym, *pend = sym + sizeof(sym);

From: Linus Torvalds torvalds@linux-foundation.org

[ Upstream commit 22f5468731491e53356ba7c028f0fdea20b18e2c ]

This clarifies the rules for min()/max()/clamp() type checking and makes them a much more efficient macro expansion.

In particular, we now look at the type and range of the inputs to see whether they work together, generating a mask of acceptable comparisons, and then just verifying that the inputs have a shared case:

- an expression with a signed type can be used for (1) signed comparisons (2) unsigned comparisons if it is statically known to have a non-negative value

- an expression with an unsigned type can be used for (3) unsigned comparison (4) signed comparisons if the type is smaller than 'int' and thus the C integer promotion rules will make it signed anyway

Here rule (1) and (3) are obvious, and rule (2) is important in order to allow obvious trivial constants to be used together with unsigned values.

Rule (4) is not necessarily a good idea, but matches what we used to do, and we have extant cases of this situation in the kernel. Notably with bcachefs having an expression like

min(bch2_bucket_sectors_dirty(a), ca->mi.bucket_size)

where bch2_bucket_sectors_dirty() returns an 's64', and 'ca->mi.bucket_size' is of type 'u16'.

Technically that bcachefs comparison is clearly sensible on a C type level, because the 'u16' will go through the normal C integer promotion, and become 'int', and then we're comparing two signed values and everything looks sane.

However, it's not entirely clear that a 'min(s64,u16)' operation makes a lot of conceptual sense, and it's possible that we will remove rule (4). After all, the _reason_ we have these complicated type checks is exactly that the C type promotion rules are not very intuitive.

But at least for now the rule is in place for backwards compatibility.

Also note that rule (2) existed before, but is hugely relaxed by this commit. It used to be true only for the simplest compile-time non-negative integer constants. The new macro model will allow cases where the compiler can trivially see that an expression is non-negative even if it isn't necessarily a constant.

For example, the amdgpu driver does

min_t(size_t, sizeof(fru_info->serial), pia[addr] & 0x3F));

because our old 'min()' macro would see that 'pia[addr] & 0x3F' is of type 'int' and clearly not a C constant expression, so doing a 'min()' with a 'size_t' is a signedness violation.

Our new 'min()' macro still sees that 'pia[addr] & 0x3F' is of type 'int', but is smart enough to also see that it is clearly non-negative, and thus would allow that case without any complaints.

Cc: Arnd Bergmann arnd@kernel.org Cc: David Laight David.Laight@aculab.com Cc: Lorenzo Stoakes lorenzo.stoakes@oracle.com Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Eliav Farber farbere@amazon.com --- include/linux/compiler.h | 9 +++++ include/linux/minmax.h | 74 ++++++++++++++++++++++++++++++++-------- 2 files changed, 68 insertions(+), 15 deletions(-)

diff --git a/include/linux/compiler.h b/include/linux/compiler.h index 004a030d5ad2..28b21e372751 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -251,6 +251,15 @@ static inline void *offset_to_ptr(const int *off) */ #define is_signed_type(type) (((type)(-1)) < (__force type)1)

+/* + * Useful shorthand for "is this condition known at compile-time?" + * + * Note that the condition may involve non-constant values, + * but the compiler may know enough about the details of the + * values to determine that the condition is statically true. + */ +#define statically_true(x) (__builtin_constant_p(x) && (x)) + /* * This is needed in functions which generate the stack canary, see * arch/x86/kernel/smpboot.c::start_secondary() for an example. diff --git a/include/linux/minmax.h b/include/linux/minmax.h index e3e4353df983..41da6f85a407 100644 --- a/include/linux/minmax.h +++ b/include/linux/minmax.h @@ -26,19 +26,63 @@ #define __typecheck(x, y) \ (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))

-/* is_signed_type() isn't a constexpr for pointer types */ -#define __is_signed(x) \ - __builtin_choose_expr(__is_constexpr(is_signed_type(typeof(x))), \ - is_signed_type(typeof(x)), 0) +/* + * __sign_use for integer expressions: + * bit #0 set if ok for unsigned comparisons + * bit #1 set if ok for signed comparisons + * + * In particular, statically non-negative signed integer + * expressions are ok for both. + * + * NOTE! Unsigned types smaller than 'int' are implicitly + * converted to 'int' in expressions, and are accepted for + * signed conversions for now. This is debatable. + * + * Note that 'x' is the original expression, and 'ux' is + * the unique variable that contains the value. + * + * We use 'ux' for pure type checking, and 'x' for when + * we need to look at the value (but without evaluating + * it for side effects! Careful to only ever evaluate it + * with sizeof() or __builtin_constant_p() etc). + * + * Pointers end up being checked by the normal C type + * rules at the actual comparison, and these expressions + * only need to be careful to not cause warnings for + * pointer use. + */ +#define __signed_type_use(x,ux) (2+__is_nonneg(x,ux)) +#define __unsigned_type_use(x,ux) (1+2*(sizeof(ux)<4)) +#define __sign_use(x,ux) (is_signed_type(typeof(ux))? \ + __signed_type_use(x,ux):__unsigned_type_use(x,ux)) + +/* + * To avoid warnings about casting pointers to integers + * of different sizes, we need that special sign type. + * + * On 64-bit we can just always use 'long', since any + * integer or pointer type can just be cast to that. + * + * This does not work for 128-bit signed integers since + * the cast would truncate them, but we do not use s128 + * types in the kernel (we do use 'u128', but they will + * be handled by the !is_signed_type() case). + * + * NOTE! The cast is there only to avoid any warnings + * from when values that aren't signed integer types. + */ +#ifdef CONFIG_64BIT + #define __signed_type(ux) long +#else + #define __signed_type(ux) typeof(__builtin_choose_expr(sizeof(ux)>4,1LL,1L)) +#endif +#define __is_nonneg(x,ux) statically_true((__signed_type(ux))(x)>=0)

-/* True for a non-negative signed int constant */ -#define __is_noneg_int(x) \ - (__builtin_choose_expr(__is_constexpr(x) && __is_signed(x), x, -1) >= 0) +#define __types_ok(x,y,ux,uy) \ + (__sign_use(x,ux) & __sign_use(y,uy))

-#define __types_ok(x, y, ux, uy) \ - (__is_signed(ux) == __is_signed(uy) || \ - __is_signed((ux) + 0) == __is_signed((uy) + 0) || \ - __is_noneg_int(x) || __is_noneg_int(y)) +#define __types_ok3(x,y,z,ux,uy,uz) \ + (__sign_use(x,ux) & __sign_use(y,uy) & __sign_use(z,uz))

#define __cmp_op_min < #define __cmp_op_max > @@ -53,8 +97,8 @@

#define __careful_cmp_once(op, x, y, ux, uy) ({ \ __auto_type ux = (x); __auto_type uy = (y); \ - static_assert(__types_ok(x, y, ux, uy), \ - #op "(" #x ", " #y ") signedness error, fix types or consider u" #op "() before " #op "_t()"); \ + BUILD_BUG_ON_MSG(!__types_ok(x,y,ux,uy), \ + #op"("#x", "#y") signedness error"); \ __cmp(op, ux, uy); })

#define __careful_cmp(op, x, y) \ @@ -70,8 +114,8 @@ static_assert(__builtin_choose_expr(__is_constexpr((lo) > (hi)), \ (lo) <= (hi), true), \ "clamp() low limit " #lo " greater than high limit " #hi); \ - static_assert(__types_ok(uval, lo, uval, ulo), "clamp() 'lo' signedness error"); \ - static_assert(__types_ok(uval, hi, uval, uhi), "clamp() 'hi' signedness error"); \ + BUILD_BUG_ON_MSG(!__types_ok3(val,lo,hi,uval,ulo,uhi), \ + "clamp("#val", "#lo", "#hi") signedness error"); \ __clamp(uval, ulo, uhi); })

#define __careful_clamp(val, lo, hi) \

From: David Laight David.Laight@ACULAB.COM

[ Upstream commit 71ee9b16251ea4bf7c1fe222517c82bdb3220acc ]

Patch series "minmax.h: Cleanups and minor optimisations".

Some tidyups and minor changes to minmax.h.

This patch (of 7):

Link: https://lkml.kernel.org/r/c50365d214e04f9ba256d417c8bebbc0@AcuMS.aculab.com Link: https://lkml.kernel.org/r/f04b2e1310244f62826267346fde0553@AcuMS.aculab.com Signed-off-by: David Laight david.laight@aculab.com Cc: Andy Shevchenko andriy.shevchenko@linux.intel.com Cc: Arnd Bergmann arnd@kernel.org Cc: Christoph Hellwig hch@infradead.org Cc: Dan Carpenter dan.carpenter@linaro.org Cc: Jason A. Donenfeld Jason@zx2c4.com Cc: Jens Axboe axboe@kernel.dk Cc: Lorenzo Stoakes lorenzo.stoakes@oracle.com Cc: Mateusz Guzik mjguzik@gmail.com Cc: Matthew Wilcox willy@infradead.org Cc: Pedro Falcato pedro.falcato@gmail.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Eliav Farber farbere@amazon.com --- include/linux/minmax.h | 34 +++++++++++++++++----------------- 1 file changed, 17 insertions(+), 17 deletions(-)

diff --git a/include/linux/minmax.h b/include/linux/minmax.h index 98008dd92153..51b0d988e322 100644 --- a/include/linux/minmax.h +++ b/include/linux/minmax.h @@ -51,10 +51,10 @@ * only need to be careful to not cause warnings for * pointer use. */ -#define __signed_type_use(x,ux) (2+__is_nonneg(x,ux)) -#define __unsigned_type_use(x,ux) (1+2*(sizeof(ux)<4)) -#define __sign_use(x,ux) (is_signed_type(typeof(ux))? \ - __signed_type_use(x,ux):__unsigned_type_use(x,ux)) +#define __signed_type_use(x, ux) (2 + __is_nonneg(x, ux)) +#define __unsigned_type_use(x, ux) (1 + 2 * (sizeof(ux) < 4)) +#define __sign_use(x, ux) (is_signed_type(typeof(ux)) ? \ + __signed_type_use(x, ux) : __unsigned_type_use(x, ux))

/* * To avoid warnings about casting pointers to integers @@ -74,15 +74,15 @@ #ifdef CONFIG_64BIT #define __signed_type(ux) long #else - #define __signed_type(ux) typeof(__builtin_choose_expr(sizeof(ux)>4,1LL,1L)) + #define __signed_type(ux) typeof(__builtin_choose_expr(sizeof(ux) > 4, 1LL, 1L)) #endif -#define __is_nonneg(x,ux) statically_true((__signed_type(ux))(x)>=0) +#define __is_nonneg(x, ux) statically_true((__signed_type(ux))(x) >= 0)

-#define __types_ok(x,y,ux,uy) \ - (__sign_use(x,ux) & __sign_use(y,uy)) +#define __types_ok(x, y, ux, uy) \ + (__sign_use(x, ux) & __sign_use(y, uy))

-#define __types_ok3(x,y,z,ux,uy,uz) \ - (__sign_use(x,ux) & __sign_use(y,uy) & __sign_use(z,uz)) +#define __types_ok3(x, y, z, ux, uy, uz) \ + (__sign_use(x, ux) & __sign_use(y, uy) & __sign_use(z, uz))

#define __cmp_op_min < #define __cmp_op_max > @@ -97,7 +97,7 @@

#define __careful_cmp_once(op, x, y, ux, uy) ({ \ __auto_type ux = (x); __auto_type uy = (y); \ - BUILD_BUG_ON_MSG(!__types_ok(x,y,ux,uy), \ + BUILD_BUG_ON_MSG(!__types_ok(x, y, ux, uy), \ #op"("#x", "#y") signedness error"); \ __cmp(op, ux, uy); })

@@ -114,7 +114,7 @@ static_assert(__builtin_choose_expr(__is_constexpr((lo) > (hi)), \ (lo) <= (hi), true), \ "clamp() low limit " #lo " greater than high limit " #hi); \ - BUILD_BUG_ON_MSG(!__types_ok3(val,lo,hi,uval,ulo,uhi), \ + BUILD_BUG_ON_MSG(!__types_ok3(val, lo, hi, uval, ulo, uhi), \ "clamp("#val", "#lo", "#hi") signedness error"); \ __clamp(uval, ulo, uhi); })

@@ -154,7 +154,7 @@

#define __careful_op3(op, x, y, z, ux, uy, uz) ({ \ __auto_type ux = (x); __auto_type uy = (y);__auto_type uz = (z);\ - BUILD_BUG_ON_MSG(!__types_ok3(x,y,z,ux,uy,uz), \ + BUILD_BUG_ON_MSG(!__types_ok3(x, y, z, ux, uy, uz), \ #op"3("#x", "#y", "#z") signedness error"); \ __cmp(op, ux, __cmp(op, uy, uz)); })

@@ -326,9 +326,9 @@ static inline bool in_range32(u32 val, u32 start, u32 len) * Use these carefully: no type checking, and uses the arguments * multiple times. Use for obvious constants only. */ -#define MIN(a,b) __cmp(min,a,b) -#define MAX(a,b) __cmp(max,a,b) -#define MIN_T(type,a,b) __cmp(min,(type)(a),(type)(b)) -#define MAX_T(type,a,b) __cmp(max,(type)(a),(type)(b)) +#define MIN(a, b) __cmp(min, a, b) +#define MAX(a, b) __cmp(max, a, b) +#define MIN_T(type, a, b) __cmp(min, (type)(a), (type)(b)) +#define MAX_T(type, a, b) __cmp(max, (type)(a), (type)(b))

#endif /* _LINUX_MINMAX_H */

From: David Laight David.Laight@ACULAB.COM

[ Upstream commit b280bb27a9f7c91ddab730e1ad91a9c18a051f41 ]

Since the test for signed values being non-negative only relies on __builtion_constant_p() (not is_constexpr()) it can use the 'ux' variable instead of the caller supplied expression. This means that the #define parameters are only expanded twice. Once in the code and once quoted in the error message.

Link: https://lkml.kernel.org/r/051afc171806425da991908ed8688a98@AcuMS.aculab.com Signed-off-by: David Laight david.laight@aculab.com Cc: Andy Shevchenko andriy.shevchenko@linux.intel.com Cc: Arnd Bergmann arnd@kernel.org Cc: Christoph Hellwig hch@infradead.org Cc: Dan Carpenter dan.carpenter@linaro.org Cc: Jason A. Donenfeld Jason@zx2c4.com Cc: Jens Axboe axboe@kernel.dk Cc: Lorenzo Stoakes lorenzo.stoakes@oracle.com Cc: Mateusz Guzik mjguzik@gmail.com Cc: Matthew Wilcox willy@infradead.org Cc: Pedro Falcato pedro.falcato@gmail.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Eliav Farber farbere@amazon.com --- include/linux/minmax.h | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/include/linux/minmax.h b/include/linux/minmax.h index 24e4b372649a..6f7ea669d305 100644 --- a/include/linux/minmax.h +++ b/include/linux/minmax.h @@ -46,10 +46,10 @@ * comparison, and these expressions only need to be careful to not cause * warnings for pointer use. */ -#define __signed_type_use(x, ux) (2 + __is_nonneg(x, ux)) -#define __unsigned_type_use(x, ux) (1 + 2 * (sizeof(ux) < 4)) -#define __sign_use(x, ux) (is_signed_type(typeof(ux)) ? \ - __signed_type_use(x, ux) : __unsigned_type_use(x, ux)) +#define __signed_type_use(ux) (2 + __is_nonneg(ux)) +#define __unsigned_type_use(ux) (1 + 2 * (sizeof(ux) < 4)) +#define __sign_use(ux) (is_signed_type(typeof(ux)) ? \ + __signed_type_use(ux) : __unsigned_type_use(ux))

/* * Check whether a signed value is always non-negative. @@ -71,13 +71,13 @@ #else #define __signed_type(ux) typeof(__builtin_choose_expr(sizeof(ux) > 4, 1LL, 1L)) #endif -#define __is_nonneg(x, ux) statically_true((__signed_type(ux))(x) >= 0) +#define __is_nonneg(ux) statically_true((__signed_type(ux))(ux) >= 0)

-#define __types_ok(x, y, ux, uy) \ - (__sign_use(x, ux) & __sign_use(y, uy)) +#define __types_ok(ux, uy) \ + (__sign_use(ux) & __sign_use(uy))

-#define __types_ok3(x, y, z, ux, uy, uz) \ - (__sign_use(x, ux) & __sign_use(y, uy) & __sign_use(z, uz)) +#define __types_ok3(ux, uy, uz) \ + (__sign_use(ux) & __sign_use(uy) & __sign_use(uz))

#define __cmp_op_min < #define __cmp_op_max > @@ -92,7 +92,7 @@

#define __careful_cmp_once(op, x, y, ux, uy) ({ \ __auto_type ux = (x); __auto_type uy = (y); \ - BUILD_BUG_ON_MSG(!__types_ok(x, y, ux, uy), \ + BUILD_BUG_ON_MSG(!__types_ok(ux, uy), \ #op"("#x", "#y") signedness error"); \ __cmp(op, ux, uy); })

@@ -109,7 +109,7 @@ static_assert(__builtin_choose_expr(__is_constexpr((lo) > (hi)), \ (lo) <= (hi), true), \ "clamp() low limit " #lo " greater than high limit " #hi); \ - BUILD_BUG_ON_MSG(!__types_ok3(val, lo, hi, uval, ulo, uhi), \ + BUILD_BUG_ON_MSG(!__types_ok3(uval, ulo, uhi), \ "clamp("#val", "#lo", "#hi") signedness error"); \ __clamp(uval, ulo, uhi); })

@@ -149,7 +149,7 @@

#define __careful_op3(op, x, y, z, ux, uy, uz) ({ \ __auto_type ux = (x); __auto_type uy = (y);__auto_type uz = (z);\ - BUILD_BUG_ON_MSG(!__types_ok3(x, y, z, ux, uy, uz), \ + BUILD_BUG_ON_MSG(!__types_ok3(ux, uy, uz), \ #op"3("#x", "#y", "#z") signedness error"); \ __cmp(op, ux, __cmp(op, uy, uz)); })

From: David Laight David.Laight@ACULAB.COM

[ Upstream commit c3939872ee4a6b8bdcd0e813c66823b31e6e26f7 ]

At some point the definitions for clamp() got added in the middle of the ones for min() and max(). Re-order the definitions so they are more sensibly grouped.

Link: https://lkml.kernel.org/r/8bb285818e4846469121c8abc3dfb6e2@AcuMS.aculab.com Signed-off-by: David Laight david.laight@aculab.com Cc: Andy Shevchenko andriy.shevchenko@linux.intel.com Cc: Arnd Bergmann arnd@kernel.org Cc: Christoph Hellwig hch@infradead.org Cc: Dan Carpenter dan.carpenter@linaro.org Cc: Jason A. Donenfeld Jason@zx2c4.com Cc: Jens Axboe axboe@kernel.dk Cc: Lorenzo Stoakes lorenzo.stoakes@oracle.com Cc: Mateusz Guzik mjguzik@gmail.com Cc: Matthew Wilcox willy@infradead.org Cc: Pedro Falcato pedro.falcato@gmail.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Eliav Farber farbere@amazon.com --- include/linux/minmax.h | 109 +++++++++++++++++++---------------------- 1 file changed, 51 insertions(+), 58 deletions(-)

diff --git a/include/linux/minmax.h b/include/linux/minmax.h index 91aa1b90c1bb..75fb7a6ad4c6 100644 --- a/include/linux/minmax.h +++ b/include/linux/minmax.h @@ -99,22 +99,6 @@ #define __careful_cmp(op, x, y) \ __careful_cmp_once(op, x, y, __UNIQUE_ID(x_), __UNIQUE_ID(y_))

-#define __clamp(val, lo, hi) \ - ((val) >= (hi) ? (hi) : ((val) <= (lo) ? (lo) : (val))) - -#define __clamp_once(val, lo, hi, uval, ulo, uhi) ({ \ - __auto_type uval = (val); \ - __auto_type ulo = (lo); \ - __auto_type uhi = (hi); \ - BUILD_BUG_ON_MSG(statically_true(ulo > uhi), \ - "clamp() low limit " #lo " greater than high limit " #hi); \ - BUILD_BUG_ON_MSG(!__types_ok3(uval, ulo, uhi), \ - "clamp("#val", "#lo", "#hi") signedness error"); \ - __clamp(uval, ulo, uhi); }) - -#define __careful_clamp(val, lo, hi) \ - __clamp_once(val, lo, hi, __UNIQUE_ID(v_), __UNIQUE_ID(l_), __UNIQUE_ID(h_)) - /** * min - return minimum of two values of the same or compatible types * @x: first value @@ -170,6 +154,22 @@ #define max3(x, y, z) \ __careful_op3(max, x, y, z, __UNIQUE_ID(x_), __UNIQUE_ID(y_), __UNIQUE_ID(z_))

+/** + * min_t - return minimum of two values, using the specified type + * @type: data type to use + * @x: first value + * @y: second value + */ +#define min_t(type, x, y) __cmp_once(min, type, x, y) + +/** + * max_t - return maximum of two values, using the specified type + * @type: data type to use + * @x: first value + * @y: second value + */ +#define max_t(type, x, y) __cmp_once(max, type, x, y) + /** * min_not_zero - return the minimum that is _not_ zero, unless both are zero * @x: value1 @@ -180,6 +180,22 @@ typeof(y) __y = (y); \ __x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); })

+#define __clamp(val, lo, hi) \ + ((val) >= (hi) ? (hi) : ((val) <= (lo) ? (lo) : (val))) + +#define __clamp_once(val, lo, hi, uval, ulo, uhi) ({ \ + __auto_type uval = (val); \ + __auto_type ulo = (lo); \ + __auto_type uhi = (hi); \ + BUILD_BUG_ON_MSG(statically_true(ulo > uhi), \ + "clamp() low limit " #lo " greater than high limit " #hi); \ + BUILD_BUG_ON_MSG(!__types_ok3(uval, ulo, uhi), \ + "clamp("#val", "#lo", "#hi") signedness error"); \ + __clamp(uval, ulo, uhi); }) + +#define __careful_clamp(val, lo, hi) \ + __clamp_once(val, lo, hi, __UNIQUE_ID(v_), __UNIQUE_ID(l_), __UNIQUE_ID(h_)) + /** * clamp - return a value clamped to a given range with strict typechecking * @val: current value @@ -191,28 +207,30 @@ */ #define clamp(val, lo, hi) __careful_clamp(val, lo, hi)

-/* - * ..and if you can't take the strict - * types, you can specify one yourself. - * - * Or not use min/max/clamp at all, of course. - */ - /** - * min_t - return minimum of two values, using the specified type - * @type: data type to use - * @x: first value - * @y: second value + * clamp_t - return a value clamped to a given range using a given type + * @type: the type of variable to use + * @val: current value + * @lo: minimum allowable value + * @hi: maximum allowable value + * + * This macro does no typechecking and uses temporary variables of type + * @type to make all the comparisons. */ -#define min_t(type, x, y) __cmp_once(min, type, x, y) +#define clamp_t(type, val, lo, hi) __careful_clamp((type)(val), (type)(lo), (type)(hi))

/** - * max_t - return maximum of two values, using the specified type - * @type: data type to use - * @x: first value - * @y: second value + * clamp_val - return a value clamped to a given range using val's type + * @val: current value + * @lo: minimum allowable value + * @hi: maximum allowable value + * + * This macro does no typechecking and uses temporary variables of whatever + * type the input argument @val is. This is useful when @val is an unsigned + * type and @lo and @hi are literals that will otherwise be assigned a signed + * integer type. */ -#define max_t(type, x, y) __cmp_once(max, type, x, y) +#define clamp_val(val, lo, hi) clamp_t(typeof(val), val, lo, hi)

/* * Do not check the array parameter using __must_be_array(). @@ -257,31 +275,6 @@ */ #define max_array(array, len) __minmax_array(max, array, len)

-/** - * clamp_t - return a value clamped to a given range using a given type - * @type: the type of variable to use - * @val: current value - * @lo: minimum allowable value - * @hi: maximum allowable value - * - * This macro does no typechecking and uses temporary variables of type - * @type to make all the comparisons. - */ -#define clamp_t(type, val, lo, hi) __careful_clamp((type)(val), (type)(lo), (type)(hi)) - -/** - * clamp_val - return a value clamped to a given range using val's type - * @val: current value - * @lo: minimum allowable value - * @hi: maximum allowable value - * - * This macro does no typechecking and uses temporary variables of whatever - * type the input argument @val is. This is useful when @val is an unsigned - * type and @lo and @hi are literals that will otherwise be assigned a signed - * integer type. - */ -#define clamp_val(val, lo, hi) clamp_t(typeof(val), val, lo, hi) - static inline bool in_range64(u64 val, u64 start, u64 len) { return (val - start) < len;

From: David Laight David.Laight@ACULAB.COM

[ Upstream commit 2b97aaf74ed534fb838d09867d09a3ca5d795208 ]

The bodies of __signed_type_use() and __unsigned_type_use() are much the same size as their names - so put the bodies in the only line that expands them.

Similarly __signed_type() is defined separately for 64bit and then used exactly once just below.

Change the test for __signed_type from CONFIG_64BIT to one based on gcc defined macros so that the code is valid if it gets used outside of a kernel build.

Link: https://lkml.kernel.org/r/9386d1ebb8974fbabbed2635160c3975@AcuMS.aculab.com Signed-off-by: David Laight david.laight@aculab.com Cc: Andy Shevchenko andriy.shevchenko@linux.intel.com Cc: Arnd Bergmann arnd@kernel.org Cc: Christoph Hellwig hch@infradead.org Cc: Dan Carpenter dan.carpenter@linaro.org Cc: Jason A. Donenfeld Jason@zx2c4.com Cc: Jens Axboe axboe@kernel.dk Cc: Lorenzo Stoakes lorenzo.stoakes@oracle.com Cc: Mateusz Guzik mjguzik@gmail.com Cc: Matthew Wilcox willy@infradead.org Cc: Pedro Falcato pedro.falcato@gmail.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Eliav Farber farbere@amazon.com --- include/linux/minmax.h | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/include/linux/minmax.h b/include/linux/minmax.h index 2bbdd5b5e07e..eaaf5c008e4d 100644 --- a/include/linux/minmax.h +++ b/include/linux/minmax.h @@ -46,10 +46,8 @@ * comparison, and these expressions only need to be careful to not cause * warnings for pointer use. */ -#define __signed_type_use(ux) (2 + __is_nonneg(ux)) -#define __unsigned_type_use(ux) (1 + 2 * (sizeof(ux) < 4)) #define __sign_use(ux) (is_signed_type(typeof(ux)) ? \ - __signed_type_use(ux) : __unsigned_type_use(ux)) + (2 + __is_nonneg(ux)) : (1 + 2 * (sizeof(ux) < 4)))

/* * Check whether a signed value is always non-negative. @@ -57,7 +55,7 @@ * A cast is needed to avoid any warnings from values that aren't signed * integer types (in which case the result doesn't matter). * - * On 64-bit any integer or pointer type can safely be cast to 'long'. + * On 64-bit any integer or pointer type can safely be cast to 'long long'. * But on 32-bit we need to avoid warnings about casting pointers to integers * of different sizes without truncating 64-bit values so 'long' or 'long long' * must be used depending on the size of the value. @@ -66,12 +64,12 @@ * them, but we do not use s128 types in the kernel (we do use 'u128', * but they are handled by the !is_signed_type() case). */ -#ifdef CONFIG_64BIT - #define __signed_type(ux) long +#if __SIZEOF_POINTER__ == __SIZEOF_LONG_LONG__ +#define __is_nonneg(ux) statically_true((long long)(ux) >= 0) #else - #define __signed_type(ux) typeof(__builtin_choose_expr(sizeof(ux) > 4, 1LL, 1L)) +#define __is_nonneg(ux) statically_true( \ + (typeof(__builtin_choose_expr(sizeof(ux) > 4, 1LL, 1L)))(ux) >= 0) #endif -#define __is_nonneg(ux) statically_true((__signed_type(ux))(ux) >= 0)

#define __types_ok(ux, uy) \ (__sign_use(ux) & __sign_use(uy))