region_intersects() checks if a specified region partially overlaps or fully eclipses a resource identified by @name. It currently sets resource flags statically, which prevents the caller from specifying a non-RAM region, such as persistent memory. Add @flags so that any region can be specified to the function. A helper function, region_intersects_ram(), is added so that the callers that check a RAM region do not have to specify its iomem resource name and flags. This interface is exported for modules, such as the EINJ driver. Signed-off-by: Toshi Kani <toshi.kani(a)hpe.com&gt; Reviewed-by: Dan Williams <dan.j.williams(a)intel.com&gt; Cc: Andrew Morton <akpm(a)linux-foundation.org&gt; Cc: Vishal Verma <vishal.l.verma(a)intel.com&gt; --- include/linux/mm.h | 4 +++- kernel/memremap.c | 5 ++--- kernel/resource.c | 23 ++++++++++++++++------- 3 files changed, 21 insertions(+), 11 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 00bad77..c776af3 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -362,7 +362,9 @@ enum { REGION_MIXED, }; -int region_intersects(resource_size_t offset, size_t size, const char *type); +int region_intersects(resource_size_t offset, size_t size, const char *type, + unsigned long flags); +int region_intersects_ram(resource_size_t offset, size_t size); /* Support for virtually mapped pages */ struct page *vmalloc_to_page(const void *addr); diff --git a/kernel/memremap.c b/kernel/memremap.c index 7658d32..98f52f1 100644 --- a/kernel/memremap.c +++ b/kernel/memremap.c @@ -57,7 +57,7 @@ static void *try_ram_remap(resource_size_t offset, size_t size) */ void *memremap(resource_size_t offset, size_t size, unsigned long flags) { - int is_ram = region_intersects(offset, size, "System RAM"); + int is_ram = region_intersects_ram(offset, size); void *addr = NULL; if (is_ram == REGION_MIXED) { @@ -162,8 +162,7 @@ static void devm_memremap_pages_release(struct device *dev, void *res) void *devm_memremap_pages(struct device *dev, struct resource *res) { - int is_ram = region_intersects(res->start, resource_size(res), - "System RAM"); + int is_ram = region_intersects_ram(res->start, resource_size(res)); struct page_map *page_map; int error, nid; diff --git a/kernel/resource.c b/kernel/resource.c index f150dbb..15c133e 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -497,6 +497,7 @@ EXPORT_SYMBOL_GPL(page_is_ram); * @start: region start address * @size: size of region * @name: name of resource (in iomem_resource) + * @flags: flags of resource (in iomem_resource) * * Check if the specified region partially overlaps or fully eclipses a * resource identified by @name. Return REGION_DISJOINT if the region @@ -504,15 +505,11 @@ EXPORT_SYMBOL_GPL(page_is_ram); * @type and another resource, and return REGION_INTERSECTS if the * region overlaps @type and no other defined resource. Note, that * REGION_INTERSECTS is also returned in the case when the specified - * region overlaps RAM and undefined memory holes. - * - * region_intersect() is used by memory remapping functions to ensure - * the user is not remapping RAM and is a vast speed up over walking - * through the resource table page by page. + * region overlaps with undefined memory holes. */ -int region_intersects(resource_size_t start, size_t size, const char *name) +int region_intersects(resource_size_t start, size_t size, const char *name, + unsigned long flags) { - unsigned long flags = IORESOURCE_MEM | IORESOURCE_BUSY; resource_size_t end = start + size - 1; int type = 0; int other = 0; struct resource *p; @@ -539,6 +536,18 @@ int region_intersects(resource_size_t start, size_t size, const char *name) return REGION_DISJOINT; } +/* + * region_intersect_ram() is used by memory remapping functions to ensure + * the user is not remapping RAM and is a vast speed up over walking + * through the resource table page by page. + */ +int region_intersects_ram(resource_size_t start, size_t size) +{ + return region_intersects(start, size, "System RAM", + IORESOURCE_MEM | IORESOURCE_BUSY); +} +EXPORT_SYMBOL_GPL(region_intersects_ram); + void __weak arch_remove_reservations(struct resource *avail) { }

On Tue, Dec 1, 2015 at 5:50 AM, Borislav Petkov <bp(a)alien8.de&gt; wrote: At least in the case of region_intersects() I was just following existing strcmp() convention from walk_system_ram_range. We could define 'const char *system_ram = "System RAM"' somewhere and then do pointer comparisons to cut down on the thrash of adding new flags to 'struct resource'?

On Tue, Dec 01, 2015 at 08:54:23AM -0800, Dan Williams wrote: Oh sure, I didn't mean you. I was simply questioning that whole identify-resource-by-its-name approach. And that came with: 67cf13ceed89 ("x86: optimize resource lookups for ioremap") I just think it is silly and that we should be identifying resource things in a more robust way. Btw, the ->name thing in struct resource has been there since a *long* time, added by: commit 40f6b7cc623f95d2a08b9adae7a6793055af4768 Author: linus1 <torvalds(a)linuxfoundation.org&gt; Date: Wed Jun 30 11:00:00 1999 -0600 Import 2.3.11pre1 I'm not sure what it was used for, perhaps for human-readable output in /proc/iomem. Let me CC Linus, he would know, most likely. akpm is already on CC. See above. I think flags or type_flags or so should be cleaner/better... I could be missing some aspect though, according to which, the name is the proper way to ident those but I can't think of one... -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply.

Add region_intersects_pmem(), which checks if a specified address range is persistent memory registered as "Persistent Memory" in the iomem_resource list. Note, it does not support legacy persistent memory registered as "Persistent Memory (legacy)". It can be supported by extending this function or a separate function, if necessary. This interface is exported so that it can be called from modules, such as the EINJ driver. Signed-off-by: Toshi Kani <toshi.kani(a)hpe.com&gt; Reviewed-by: Dan Williams <dan.j.williams(a)intel.com&gt; Cc: Andrew Morton <akpm(a)linux-foundation.org&gt; Cc: Vishal Verma <vishal.l.verma(a)intel.com&gt; --- include/linux/mm.h | 1 + kernel/resource.c | 12 ++++++++++++ 2 files changed, 13 insertions(+) diff --git a/include/linux/mm.h b/include/linux/mm.h index c776af3..3825879 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -365,6 +365,7 @@ enum { int region_intersects(resource_size_t offset, size_t size, const char *type, unsigned long flags); int region_intersects_ram(resource_size_t offset, size_t size); +int region_intersects_pmem(resource_size_t offset, size_t size); /* Support for virtually mapped pages */ struct page *vmalloc_to_page(const void *addr); diff --git a/kernel/resource.c b/kernel/resource.c index 15c133e..5230e63 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -548,6 +548,18 @@ int region_intersects_ram(resource_size_t start, size_t size) } EXPORT_SYMBOL_GPL(region_intersects_ram); +/* + * region_intersects_pmem() checks if a specified address range is + * persistent memory, registered as "Persistent Memory", in the + * iomem_resource list. + */ +int region_intersects_pmem(resource_size_t start, size_t size) +{ + return region_intersects(start, size, "Persistent Memory", + IORESOURCE_MEM); +} +EXPORT_SYMBOL_GPL(region_intersects_pmem); + void __weak arch_remove_reservations(struct resource *avail) { }