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Message-Id: <1403814824-7587-7-git-send-email-vgoyal@redhat.com>
Date: Thu, 26 Jun 2014 16:33:35 -0400
From: Vivek Goyal <vgoyal@...hat.com>
To: linux-kernel@...r.kernel.org, kexec@...ts.infradead.org
Cc: ebiederm@...ssion.com, hpa@...or.com, mjg59@...f.ucam.org,
greg@...ah.com, bp@...en8.de, dyoung@...hat.com,
chaowang@...hat.com, bhe@...hat.com, akpm@...ux-foundation.org,
Vivek Goyal <vgoyal@...hat.com>,
Yinghai Lu <yinghai@...nel.org>
Subject: [PATCH 06/15] 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: Vivek Goyal <vgoyal@...hat.com>
Cc: Yinghai Lu <yinghai@...nel.org>
---
include/linux/ioport.h | 6 +++
kernel/resource.c | 101 ++++++++++++++++++++++++++++++++++++++++++++-----
2 files changed, 98 insertions(+), 9 deletions(-)
diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index 5e3a906..142ec54 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -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)
diff --git a/kernel/resource.c b/kernel/resource.c
index 3c2237a..da14b8d 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -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;
@@ -365,6 +384,70 @@ static int find_next_system_ram(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
+ * 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.
* Now, this function is only for "System RAM".
@@ -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)
--
1.9.0
--
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