From: Bjorn Helgaas bhelgaas@google.com
[ Upstream commit 010a93bf97c72f43aac664d0a685942f83d1a103 ]
Previously find_next_iomem_res() used "*res" as both an input parameter for the range to search and the type of resource to search for, and an output parameter for the resource we found, which makes the interface confusing.
The current callers use find_next_iomem_res() incorrectly because they allocate a single struct resource and use it for repeated calls to find_next_iomem_res(). When find_next_iomem_res() returns a resource, it overwrites the start, end, flags, and desc members of the struct. If we call find_next_iomem_res() again, we must update or restore these fields. The previous code restored res.start and res.end, but not res.flags or res.desc.
Since the callers did not restore res.flags, if they searched for flags IORESOURCE_MEM | IORESOURCE_BUSY and found a resource with flags IORESOURCE_MEM | IORESOURCE_BUSY | IORESOURCE_SYSRAM, the next search would incorrectly skip resources unless they were also marked as IORESOURCE_SYSRAM.
Fix this by restructuring the interface so it takes explicit "start, end, flags" parameters and uses "*res" only as an output parameter.
Based on a patch by Lianbo Jiang lijiang@redhat.com.
[ bp: While at it: - make comments kernel-doc style. -
Originally-by: http://lore.kernel.org/lkml/20180921073211.20097-2-lijiang@redhat.com Signed-off-by: Bjorn Helgaas bhelgaas@google.com Signed-off-by: Borislav Petkov bp@suse.de CC: Andrew Morton akpm@linux-foundation.org CC: Brijesh Singh brijesh.singh@amd.com CC: Dan Williams dan.j.williams@intel.com CC: H. Peter Anvin hpa@zytor.com CC: Lianbo Jiang lijiang@redhat.com CC: Takashi Iwai tiwai@suse.de CC: Thomas Gleixner tglx@linutronix.de CC: Tom Lendacky thomas.lendacky@amd.com CC: Vivek Goyal vgoyal@redhat.com CC: Yaowei Bai baiyaowei@cmss.chinamobile.com CC: bhe@redhat.com CC: dan.j.williams@intel.com CC: dyoung@redhat.com CC: kexec@lists.infradead.org CC: mingo@redhat.com CC: x86-ml x86@kernel.org Link: http://lkml.kernel.org/r/153805812916.1157.177580438135143788.stgit@bhelgaas... Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/resource.c | 96 +++++++++++++++++++++-------------------------- 1 file changed, 42 insertions(+), 54 deletions(-)
diff --git a/kernel/resource.c b/kernel/resource.c index 155ec873ea4d1..38b8d11c9eaf4 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -318,24 +318,27 @@ int release_resource(struct resource *old)
EXPORT_SYMBOL(release_resource);
-/* - * Finds the lowest iomem resource existing within [res->start..res->end]. - * The caller must specify res->start, res->end, res->flags, and optionally - * desc. If found, returns 0, res is overwritten, if not found, returns -1. - * This function walks the whole tree and not just first level children until - * and unless first_level_children_only is true. +/** + * Finds the lowest iomem resource that covers part of [start..end]. The + * caller must specify start, end, flags, and desc (which may be + * IORES_DESC_NONE). + * + * If a resource is found, returns 0 and *res is overwritten with the part + * of the resource that's within [start..end]; if none is found, returns + * -1. + * + * This function walks the whole tree and not just first level children + * unless @first_level_children_only is true. */ -static int find_next_iomem_res(struct resource *res, unsigned long desc, - bool first_level_children_only) +static int find_next_iomem_res(resource_size_t start, resource_size_t end, + unsigned long flags, unsigned long desc, + bool first_level_children_only, + struct resource *res) { - resource_size_t start, end; struct resource *p; bool sibling_only = false;
BUG_ON(!res); - - start = res->start; - end = res->end; BUG_ON(start >= end);
if (first_level_children_only) @@ -344,7 +347,7 @@ static int find_next_iomem_res(struct resource *res, unsigned long desc, read_lock(&resource_lock);
for (p = iomem_resource.child; p; p = next_resource(p, sibling_only)) { - if ((p->flags & res->flags) != res->flags) + if ((p->flags & flags) != flags) continue; if ((desc != IORES_DESC_NONE) && (desc != p->desc)) continue; @@ -359,32 +362,31 @@ static int find_next_iomem_res(struct resource *res, unsigned long desc, read_unlock(&resource_lock); if (!p) return -1; + /* copy data */ - if (res->start < p->start) - res->start = p->start; - if (res->end > p->end) - res->end = p->end; + res->start = max(start, p->start); + res->end = min(end, p->end); res->flags = p->flags; res->desc = p->desc; return 0; }
-static int __walk_iomem_res_desc(struct resource *res, unsigned long desc, - bool first_level_children_only, - void *arg, +static int __walk_iomem_res_desc(resource_size_t start, resource_size_t end, + unsigned long flags, unsigned long desc, + bool first_level_children_only, void *arg, int (*func)(struct resource *, void *)) { - u64 orig_end = res->end; + struct resource res; int ret = -1;
- while ((res->start < res->end) && - !find_next_iomem_res(res, desc, first_level_children_only)) { - ret = (*func)(res, arg); + while (start < end && + !find_next_iomem_res(start, end, flags, desc, + first_level_children_only, &res)) { + ret = (*func)(&res, arg); if (ret) break;
- res->start = res->end + 1; - res->end = orig_end; + start = res.end + 1; }
return ret; @@ -407,13 +409,7 @@ static int __walk_iomem_res_desc(struct resource *res, unsigned long desc, int walk_iomem_res_desc(unsigned long desc, unsigned long flags, u64 start, u64 end, void *arg, int (*func)(struct resource *, void *)) { - struct resource res; - - res.start = start; - res.end = end; - res.flags = flags; - - return __walk_iomem_res_desc(&res, desc, false, arg, func); + return __walk_iomem_res_desc(start, end, flags, desc, false, arg, func); } EXPORT_SYMBOL_GPL(walk_iomem_res_desc);
@@ -427,13 +423,9 @@ EXPORT_SYMBOL_GPL(walk_iomem_res_desc); int walk_system_ram_res(u64 start, u64 end, void *arg, int (*func)(struct resource *, void *)) { - struct resource res; + unsigned long flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
- res.start = start; - res.end = end; - res.flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; - - return __walk_iomem_res_desc(&res, IORES_DESC_NONE, true, + return __walk_iomem_res_desc(start, end, flags, IORES_DESC_NONE, true, arg, func); }
@@ -444,13 +436,9 @@ int walk_system_ram_res(u64 start, u64 end, void *arg, int walk_mem_res(u64 start, u64 end, void *arg, int (*func)(struct resource *, void *)) { - struct resource res; + unsigned long flags = IORESOURCE_MEM | IORESOURCE_BUSY;
- res.start = start; - res.end = end; - res.flags = IORESOURCE_MEM | IORESOURCE_BUSY; - - return __walk_iomem_res_desc(&res, IORES_DESC_NONE, true, + return __walk_iomem_res_desc(start, end, flags, IORES_DESC_NONE, true, arg, func); }
@@ -464,25 +452,25 @@ int walk_mem_res(u64 start, u64 end, void *arg, int walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages, void *arg, int (*func)(unsigned long, unsigned long, void *)) { + resource_size_t start, end; + unsigned long flags; struct resource res; unsigned long pfn, end_pfn; - u64 orig_end; int ret = -1;
- res.start = (u64) start_pfn << PAGE_SHIFT; - res.end = ((u64)(start_pfn + nr_pages) << PAGE_SHIFT) - 1; - res.flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; - orig_end = res.end; - while ((res.start < res.end) && - (find_next_iomem_res(&res, IORES_DESC_NONE, true) >= 0)) { + start = (u64) start_pfn << PAGE_SHIFT; + end = ((u64)(start_pfn + nr_pages) << PAGE_SHIFT) - 1; + flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; + while (start < end && + !find_next_iomem_res(start, end, flags, IORES_DESC_NONE, + true, &res)) { pfn = (res.start + PAGE_SIZE - 1) >> PAGE_SHIFT; end_pfn = (res.end + 1) >> PAGE_SHIFT; if (end_pfn > pfn) ret = (*func)(pfn, end_pfn - pfn, arg); if (ret) break; - res.start = res.end + 1; - res.end = orig_end; + start = res.end + 1; } return ret; }