The patch titled
clean up add_bd_holder()
has been added to the -mm tree. Its filename is
clean-up-add_bd_holder.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: clean up add_bd_holder()
From: "Jun'ichi Nomura" <j-nomura@xxxxxxxxxxxxx>
add_bd_holder() is called from bd_claim_by_kobject to put a given struct
bd_holder in the list if there is no matching entry.
There are 3 possible results of add_bd_holder():
1. there is no matching entry and add the given one to the list
2. there is matching entry, so just increment reference count of
the existing one
3. something failed during its course
1 and 2 are success. But for the case 2, someone has to free
the unused struct bd_holder.
Current 2.6.19-rc3 code frees it inside of add_bd_holder and returns same
value 0 for both cases 1 and 2. However, it's natural and less error-prone
if caller frees it since it's allocated by the caller.
Signed-off-by: Jun'ichi Nomura <j-nomura@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
fs/block_dev.c | 53 +++++++++++++++++++++++++++++++----------------
1 files changed, 35 insertions(+), 18 deletions(-)
diff -puN fs/block_dev.c~clean-up-add_bd_holder fs/block_dev.c
--- a/fs/block_dev.c~clean-up-add_bd_holder
+++ a/fs/block_dev.c
@@ -642,16 +642,38 @@ static void free_bd_holder(struct bd_hol
}
/**
+ * find_bd_holder - find matching struct bd_holder from the block device
+ *
+ * @bdev: struct block device to be searched
+ * @bo: target struct bd_holder
+ *
+ * Returns matching entry with @bo in @bdev->bd_holder_list.
+ * If found, increment the reference count and return the pointer.
+ * If not found, returns NULL.
+ */
+static int find_bd_holder(struct block_device *bdev, struct bd_holder *bo)
+{
+ struct bd_holder *tmp;
+
+ list_for_each_entry(tmp, &bdev->bd_holder_list, list)
+ if (tmp->sdir == bo->sdir) {
+ tmp->count++;
+ return tmp;
+ }
+
+ return NULL;
+}
+
+/**
* add_bd_holder - create sysfs symlinks for bd_claim() relationship
*
* @bdev: block device to be bd_claimed
* @bo: preallocated and initialized by alloc_bd_holder()
*
- * If there is no matching entry with @bo in @bdev->bd_holder_list,
- * add @bo to the list, create symlinks.
+ * Add @bo to @bdev->bd_holder_list, create symlinks.
*
- * Returns 0 if symlinks are created or already there.
- * Returns -ve if something fails and @bo can be freed.
+ * Returns 0 if symlinks are created.
+ * Returns -ve if something fails.
*/
static int add_bd_holder(struct block_device *bdev, struct bd_holder *bo)
{
@@ -661,15 +683,6 @@ static int add_bd_holder(struct block_de
if (!bo)
return -EINVAL;
- list_for_each_entry(tmp, &bdev->bd_holder_list, list) {
- if (tmp->sdir == bo->sdir) {
- tmp->count++;
- /* We've already done what we need to do here. */
- free_bd_holder(bo);
- return 0;
- }
- }
-
if (!bd_holder_grab_dirs(bdev, bo))
return -EBUSY;
@@ -740,7 +753,7 @@ static int bd_claim_by_kobject(struct bl
struct kobject *kobj)
{
int res;
- struct bd_holder *bo;
+ struct bd_holder *bo, *found;
if (!kobj)
return -EINVAL;
@@ -752,11 +765,15 @@ static int bd_claim_by_kobject(struct bl
mutex_lock_nested(&bdev->bd_mutex, BD_MUTEX_PARTITION);
res = bd_claim(bdev, holder);
if (res == 0) {
- res = add_bd_holder(bdev, bo);
- if (res)
- bd_release(bdev);
+ found = find_bd_holder(bdev, bo);
+ if (found == NULL) {
+ res = add_bd_holder(bdev, bo);
+ if (res)
+ bd_release(bdev);
+ }
}
- if (res)
+
+ if (res || found)
free_bd_holder(bo);
mutex_unlock(&bdev->bd_mutex);
_
Patches currently in -mm which might be from j-nomura@xxxxxxxxxxxxx are
fix-bd_claim_by_kobject-error-handling.patch
clean-up-add_bd_holder.patch
-
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