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Commit 8c86e70a authored by Vivek Goyal's avatar Vivek Goyal Committed by Linus Torvalds
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resource: provide new functions to walk through resources 



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: default avatarVivek 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 255aedd9

include/linux/ioport.h

+6 −0
Original line number Diff line number Diff line
@@ -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)

kernel/resource.c

+92 −9
Original line number Diff line number Diff line
@@ -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)