[patch 10/37] dm: move idr_pre_get

Greg KH
2006-09-06T23:00:53Z

[-- Attachment #1: dm-move-idr_pre_get.patch --]
[-- Type: text/plain, Size: 1674 bytes --]

-stable review patch. If anyone has any objections, please let us know.

------------------

From: Jeff Mahoney <jeffm@suse.com>

idr_pre_get() can sleep while allocating memory.

The next patch will change _minor_lock into a spinlock, so this patch moves
idr_pre_get() outside the lock in preparation.

[akpm: too late for 2.6.17 - suitable for 2.6.17.x after it has settled]

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

drivers/md/dm.c | 23 +++++++++--------------
1 file changed, 9 insertions(+), 14 deletions(-)

--- linux-2.6.17.11.orig/drivers/md/dm.c
+++ linux-2.6.17.11/drivers/md/dm.c
@@ -766,6 +766,10 @@ static int specific_minor(struct mapped_
if (minor >= (1 << MINORBITS))
return -EINVAL;

+ r = idr_pre_get(&_minor_idr, GFP_KERNEL);
+ if (!r)
+ return -ENOMEM;
+
mutex_lock(&_minor_lock);

if (idr_find(&_minor_idr, minor)) {
@@ -773,16 +777,9 @@ static int specific_minor(struct mapped_
goto out;
}

- r = idr_pre_get(&_minor_idr, GFP_KERNEL);
- if (!r) {
- r = -ENOMEM;
- goto out;
- }
-
r = idr_get_new_above(&_minor_idr, MINOR_ALLOCED, minor, &m);
- if (r) {
+ if (r)
goto out;
- }

if (m != minor) {
idr_remove(&_minor_idr, m);
@@ -800,13 +797,11 @@ static int next_free_minor(struct mapped
int r;
unsigned int m;

- mutex_lock(&_minor_lock);
-
r = idr_pre_get(&_minor_idr, GFP_KERNEL);
- if (!r) {
- r = -ENOMEM;
- goto out;
- }
+ if (!r)
+ return -ENOMEM;
+
+ mutex_lock(&_minor_lock);

r = idr_get_new(&_minor_idr, MINOR_ALLOCED, &m);
if (r) {

--