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resource: provide new functions to walk through resources

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I have added two more functions to walk through resources.

Currently walk_system_ram_range() deals with pfn and /proc/iomem can
contain partial pages.  By dealing in pfn, callback function loses the
info that last page of a memory range is a partial page and not the full
page.  So I implemented walk_system_ram_res() which returns u64 values to
callback functions and now it properly return start and end address.

walk_system_ram_range() uses find_next_system_ram() to find the next ram
resource.  This in turn only travels through siblings of top level child
and does not travers through all the nodes of the resoruce tree.  I also
need another function where I can walk through all the resources, for
example figure out where "GART" aperture is.  Figure out where ACPI memory
is.

So I wrote another function walk_iomem_res() which walks through all
/proc/iomem resources and returns matches as asked by caller.  Caller can
specify "name" of resource, start and end and flags.

Got rid of find_next_system_ram_res() and instead implemented more generic
find_next_iomem_res() which can be used to traverse top level children
only based on an argument.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: WANG Chao <chaowang@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Vivek Goyal 2014-08-08 14:25:50 -07:00 committed by Linus Torvalds
parent 255aedd90e
commit 8c86e70ace
2 changed files with 98 additions and 9 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

6
include/linux/ioport.h
View file

@ -237,6 +237,12 @@ extern int iomem_is_exclusive(u64 addr);
extern int
walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
void *arg, int (*func)(unsigned long, unsigned long, void *));
extern int
walk_system_ram_res(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 *));
/* True if any part of r1 overlaps r2 */
static inline bool resource_overlaps(struct resource *r1, struct resource *r2)

101
kernel/resource.c
View file

@ -59,10 +59,12 @@ static DEFINE_RWLOCK(resource_lock);
static struct resource *bootmem_resource_free;
static DEFINE_SPINLOCK(bootmem_resource_lock);
static void *r_next(struct seq_file *m, void *v, loff_t *pos)
static struct resource *next_resource(struct resource *p, bool sibling_only)
{
struct resource *p = v;
(*pos)++;
/* Caller wants to traverse through siblings only */
if (sibling_only)
return p->sibling;
if (p->child)
return p->child;
while (!p->sibling && p->parent)
@ -70,6 +72,13 @@ static void *r_next(struct seq_file *m, void *v, loff_t *pos)
return p->sibling;
}
static void *r_next(struct seq_file *m, void *v, loff_t *pos)
{
struct resource *p = v;
(*pos)++;
return (void *)next_resource(p, false);
}
#ifdef CONFIG_PROC_FS
enum { MAX_IORES_LEVEL = 5 };
@ -322,16 +331,19 @@ int release_resource(struct resource *old)
EXPORT_SYMBOL(release_resource);
#if !defined(CONFIG_ARCH_HAS_WALK_MEMORY)
/*
* Finds the lowest memory reosurce exists within [res->start.res->end)
* 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.
*/
static int find_next_system_ram(struct resource *res, char *name)
static int find_next_iomem_res(struct resource *res, char *name,
bool first_level_children_only)
{
resource_size_t start, end;
struct resource *p;
bool sibling_only = false;
BUG_ON(!res);
@ -340,8 +352,14 @@ static int find_next_system_ram(struct resource *res, char *name)
BUG_ON(start >= end);
read_lock(&resource_lock);
for (p = iomem_resource.child; p ; p = p->sibling) {
/* system ram is just marked as IORESOURCE_MEM */
if (first_level_children_only) {
p = iomem_resource.child;
sibling_only = true;
} else
p = &iomem_resource;
while ((p = next_resource(p, sibling_only))) {
if (p->flags != res->flags)
continue;
if (name && strcmp(p->name, name))
@ -353,6 +371,7 @@ static int find_next_system_ram(struct resource *res, char *name)
if ((p->end >= start) && (p->start < end))
break;
}
read_unlock(&resource_lock);
if (!p)
return -1;
@ -364,6 +383,70 @@ static int find_next_system_ram(struct resource *res, char *name)
return 0;
}
/*
* 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
* name are valid candidates.
*
* @name: name of resource
* @flags: resource flags
* @start: start addr
* @end: end addr
*/
int walk_iomem_res(char *name, 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, name, false))) {
ret = (*func)(res.start, res.end, arg);
if (ret)
break;
res.start = res.end + 1;
res.end = orig_end;
}
return ret;
}
/*
* This function calls callback against all memory range of "System RAM"
* which are marked as IORESOURCE_MEM and IORESOUCE_BUSY.
* Now, this function is only for "System RAM". This function deals with
* full ranges and not pfn. If resources are not pfn aligned, dealing
* with pfn can truncate ranges.
*/
int walk_system_ram_res(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 = IORESOURCE_MEM | IORESOURCE_BUSY;
orig_end = res.end;
while ((res.start < res.end) &&
(!find_next_iomem_res(&res, "System RAM", true))) {
ret = (*func)(res.start, res.end, arg);
if (ret)
break;
res.start = res.end + 1;
res.end = orig_end;
}
return ret;
}
#if !defined(CONFIG_ARCH_HAS_WALK_MEMORY)
/*
* This function calls callback against all memory range of "System RAM"
* which are marked as IORESOURCE_MEM and IORESOUCE_BUSY.
@ -382,7 +465,7 @@ int walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
orig_end = res.end;
while ((res.start < res.end) &&
(find_next_system_ram(&res, "System RAM") >= 0)) {
(find_next_iomem_res(&res, "System RAM", true) >= 0)) {
pfn = (res.start + PAGE_SIZE - 1) >> PAGE_SHIFT;
end_pfn = (res.end + 1) >> PAGE_SHIFT;
if (end_pfn > pfn)