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resource: Add walk_iomem_res_desc() 

Add a new interface, walk_iomem_res_desc(), which walks through
the iomem table by identifying a target with @flags and @desc.
This interface provides the same functionality as
walk_iomem_res(), but does not use strcmp() to @name for better
efficiency.

walk_iomem_res() is deprecated and will be removed in a later
patch.

Requested-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
[ Fixup comments. ]
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Hanjun Guo <hanjun.guo@linaro.org>
Cc: Jakub Sitnicki <jsitnicki@gmail.com>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: linux-arch@vger.kernel.org
Cc: linux-mm <linux-mm@kvack.org>
Link: http://lkml.kernel.org/r/1453841853-11383-14-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Toshi Kani 2016-01-26 21:57:29 +01:00 committed by Ingo Molnar
parent 1c29f25bf5
commit 3f33647c41
2 changed files with 59 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
include/linux/ioport.h
View File

@ -268,6 +268,9 @@ extern int
walk_system_ram_res(u64 start, u64 end, void *arg,
int (*func)(u64, u64, void *));
extern int
walk_iomem_res_desc(unsigned long desc, unsigned long flags, u64 start, u64 end,
void *arg, int (*func)(u64, u64, void *));
extern int
walk_iomem_res(char *name, unsigned long flags, u64 start, u64 end, void *arg,
int (*func)(u64, u64, void *));

66
kernel/resource.c
View File

@ -333,14 +333,15 @@ int release_resource(struct resource *old)
EXPORT_SYMBOL(release_resource);
/*
* Finds the lowest iomem reosurce exists with-in [res->start.res->end)
* the caller must specify res->start, res->end, res->flags and "name".
* If found, returns 0, res is overwritten, if not found, returns -1.
* This walks through whole tree and not just first level children
* until and unless first_level_children_only is true.
* Finds the lowest iomem resource existing within [res->start.res->end).
* The caller must specify res->start, res->end, res->flags, and optionally
* desc and "name". 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.
*/
static int find_next_iomem_res(struct resource *res, char *name,
bool first_level_children_only)
static int find_next_iomem_res(struct resource *res, unsigned long desc,
char *name, bool first_level_children_only)
{
resource_size_t start, end;
struct resource *p;
@ -360,6 +361,8 @@ static int find_next_iomem_res(struct resource *res, char *name,
for (p = iomem_resource.child; p; p = next_resource(p, sibling_only)) {
if ((p->flags & res->flags) != res->flags)
continue;
if ((desc != IORES_DESC_NONE) && (desc != p->desc))
continue;
if (name && strcmp(p->name, name))
continue;
if (p->start > end) {
@ -385,12 +388,55 @@ static int find_next_iomem_res(struct resource *res, char *name,
* Walks through iomem resources and calls func() with matching resource
* ranges. This walks through whole tree and not just first level children.
* All the memory ranges which overlap start,end and also match flags and
* desc are valid candidates.
*
* @desc: I/O resource descriptor. Use IORES_DESC_NONE to skip @desc check.
* @flags: I/O resource flags
* @start: start addr
* @end: end addr
*
* NOTE: For a new descriptor search, define a new IORES_DESC in
* <linux/ioport.h> and set it in 'desc' of a target resource entry.
*/
int walk_iomem_res_desc(unsigned long desc, unsigned long flags, u64 start,
u64 end, void *arg, int (*func)(u64, u64, void *))
{
struct resource res;
u64 orig_end;
int ret = -1;
res.start = start;
res.end = end;
res.flags = flags;
orig_end = res.end;
while ((res.start < res.end) &&
(!find_next_iomem_res(&res, desc, NULL, false))) {
ret = (*func)(res.start, res.end, arg);
if (ret)
break;
res.start = res.end + 1;
res.end = orig_end;
}
return ret;
}
/*
* Walks through iomem resources and calls @func with matching resource
* ranges. This walks the whole tree and not just first level children.
* All the memory ranges which overlap start,end and also match flags and
* name are valid candidates.
*
* @name: name of resource
* @flags: resource flags
* @start: start addr
* @end: end addr
*
* NOTE: This function is deprecated and should not be used in new code.
* Use walk_iomem_res_desc(), instead.
*/
int walk_iomem_res(char *name, unsigned long flags, u64 start, u64 end,
void *arg, int (*func)(u64, u64, void *))
@ -404,7 +450,7 @@ int walk_iomem_res(char *name, unsigned long flags, u64 start, u64 end,
res.flags = flags;
orig_end = res.end;
while ((res.start < res.end) &&
(!find_next_iomem_res(&res, name, false))) {
(!find_next_iomem_res(&res, IORES_DESC_NONE, name, false))) {
ret = (*func)(res.start, res.end, arg);
if (ret)
break;
@ -433,7 +479,7 @@ int walk_system_ram_res(u64 start, u64 end, void *arg,
res.flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
orig_end = res.end;
while ((res.start < res.end) &&
(!find_next_iomem_res(&res, NULL, true))) {
(!find_next_iomem_res(&res, IORES_DESC_NONE, NULL, true))) {
ret = (*func)(res.start, res.end, arg);
if (ret)
break;
@ -463,7 +509,7 @@ int walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
res.flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
orig_end = res.end;
while ((res.start < res.end) &&
(find_next_iomem_res(&res, NULL, true) >= 0)) {
(find_next_iomem_res(&res, IORES_DESC_NONE, NULL, true) >= 0)) {
pfn = (res.start + PAGE_SIZE - 1) >> PAGE_SHIFT;
end_pfn = (res.end + 1) >> PAGE_SHIFT;
if (end_pfn > pfn)