This is a note to let you know that I've just added the patch titled

lib/genalloc.c: make the avail variable an atomic_long_t

to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: lib-genalloc.c-make-the-avail-variable-an-atomic_long_t.patch and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From foo@baz Tue Dec 12 13:26:17 CET 2017

From: Stephen Bates sbates@raithlin.com Date: Fri, 17 Nov 2017 15:28:16 -0800 Subject: lib/genalloc.c: make the avail variable an atomic_long_t

From: Stephen Bates sbates@raithlin.com

[ Upstream commit 36a3d1dd4e16bcd0d2ddfb4a2ec7092f0ae0d931 ]

If the amount of resources allocated to a gen_pool exceeds 2^32 then the avail atomic overflows and this causes problems when clients try and borrow resources from the pool. This is only expected to be an issue on 64 bit systems.

Add the <linux/atomic.h> header to pull in atomic_long* operations. So that 32 bit systems continue to use atomic32_t but 64 bit systems can use atomic64_t.

Link: http://lkml.kernel.org/r/1509033843-25667-1-git-send-email-sbates@raithlin.c... Signed-off-by: Stephen Bates sbates@raithlin.com Reviewed-by: Logan Gunthorpe logang@deltatee.com Reviewed-by: Mathieu Desnoyers mathieu.desnoyers@efficios.com Reviewed-by: Daniel Mentz danielmentz@google.com Cc: Jonathan Corbet corbet@lwn.net Cc: Andrew Morton akpm@linux-foundation.org Cc: Will Deacon will.deacon@arm.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Sasha Levin alexander.levin@verizon.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- include/linux/genalloc.h | 3 ++- lib/genalloc.c | 10 +++++----- 2 files changed, 7 insertions(+), 6 deletions(-)

--- a/include/linux/genalloc.h +++ b/include/linux/genalloc.h @@ -32,6 +32,7 @@

#include <linux/types.h> #include <linux/spinlock_types.h> +#include <linux/atomic.h>

struct device; struct device_node; @@ -70,7 +71,7 @@ struct gen_pool { */ struct gen_pool_chunk { struct list_head next_chunk; /* next chunk in pool */ - atomic_t avail; + atomic_long_t avail; phys_addr_t phys_addr; /* physical starting address of memory chunk */ unsigned long start_addr; /* start address of memory chunk */ unsigned long end_addr; /* end address of memory chunk (inclusive) */ --- a/lib/genalloc.c +++ b/lib/genalloc.c @@ -194,7 +194,7 @@ int gen_pool_add_virt(struct gen_pool *p chunk->phys_addr = phys; chunk->start_addr = virt; chunk->end_addr = virt + size - 1; - atomic_set(&chunk->avail, size); + atomic_long_set(&chunk->avail, size);

spin_lock(&pool->lock); list_add_rcu(&chunk->next_chunk, &pool->chunks); @@ -304,7 +304,7 @@ unsigned long gen_pool_alloc_algo(struct nbits = (size + (1UL << order) - 1) >> order; rcu_read_lock(); list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) { - if (size > atomic_read(&chunk->avail)) + if (size > atomic_long_read(&chunk->avail)) continue;

start_bit = 0; @@ -324,7 +324,7 @@ retry:

addr = chunk->start_addr + ((unsigned long)start_bit << order); size = nbits << order; - atomic_sub(size, &chunk->avail); + atomic_long_sub(size, &chunk->avail); break; } rcu_read_unlock(); @@ -390,7 +390,7 @@ void gen_pool_free(struct gen_pool *pool remain = bitmap_clear_ll(chunk->bits, start_bit, nbits); BUG_ON(remain); size = nbits << order; - atomic_add(size, &chunk->avail); + atomic_long_add(size, &chunk->avail); rcu_read_unlock(); return; } @@ -464,7 +464,7 @@ size_t gen_pool_avail(struct gen_pool *p

rcu_read_lock(); list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) - avail += atomic_read(&chunk->avail); + avail += atomic_long_read(&chunk->avail); rcu_read_unlock(); return avail; }

Patches currently in stable-queue which might be from sbates@raithlin.com are

queue-4.9/lib-genalloc.c-make-the-avail-variable-an-atomic_long_t.patch