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, but is maintained for backward
compatibility since walk_iomem_res_desc() requires 'desc' of
a target resource entry be initialized with its descriptor ID.
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Signed-off-by: Toshi Kani <toshi.kani@xxxxxxx>
---
include/linux/ioport.h | 3 ++
kernel/resource.c | 58 ++++++++++++++++++++++++++++++++++++++++++------
2 files changed, 54 insertions(+), 7 deletions(-)
diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index b7350c0..c4cd43a 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -269,6 +269,9 @@ 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 *));
diff --git a/kernel/resource.c b/kernel/resource.c
index 52e6380..579b0e1 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -334,13 +334,14 @@ 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.
+ * 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 walks through 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) {
@@ -387,10 +390,51 @@ static int find_next_iomem_res(struct resource *res, char *name,
* All the memory ranges which overlap start,end and also match flags and
* name are valid candidates.
*
+ * @desc: I/O resource descriptor. Use IORES_DESC_NONE to skip this 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 to '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 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
+ *
+ * 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 +448,7 @@ 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 +477,7 @@ 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 +507,7 @@ 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)
--
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