From: Jeff Mahoney <[email protected]>
One part of the system can attempt to use a mapped device before
another has finished initialising it or while it is being freed.
This patch introduces a place holder value, MINOR_ALLOCED, to mark the
minor as allocated but in a state where it can't be used, such as
mid-allocation or mid-free. At the end of the initialization, it
replaces the place holder with the pointer to the mapped_device,
making it available to the rest of the dm subsystem.
Signed-off-by: Jeff Mahoney <[email protected]>
Signed-Off-By: Alasdair G Kergon <[email protected]>
Index: linux-2.6.17-rc4/drivers/md/dm.c
===================================================================
--- linux-2.6.17-rc4.orig/drivers/md/dm.c 2006-05-23 18:16:30.000000000 +0100
+++ linux-2.6.17-rc4/drivers/md/dm.c 2006-05-23 18:16:42.000000000 +0100
@@ -54,6 +54,8 @@ union map_info *dm_get_mapinfo(struct bi
return NULL;
}
+#define MINOR_ALLOCED ((void *)-1)
+
/*
* Bits for the md->flags field.
*/
@@ -777,7 +779,7 @@ static int specific_minor(struct mapped_
goto out;
}
- r = idr_get_new_above(&_minor_idr, md, minor, &m);
+ r = idr_get_new_above(&_minor_idr, MINOR_ALLOCED, minor, &m);
if (r) {
goto out;
}
@@ -806,7 +808,7 @@ static int next_free_minor(struct mapped
goto out;
}
- r = idr_get_new(&_minor_idr, md, &m);
+ r = idr_get_new(&_minor_idr, MINOR_ALLOCED, &m);
if (r) {
goto out;
}
@@ -833,6 +835,7 @@ static struct mapped_device *alloc_dev(u
{
int r;
struct mapped_device *md = kmalloc(sizeof(*md), GFP_KERNEL);
+ void *old_md;
if (!md) {
DMWARN("unable to allocate device, out of memory.");
@@ -888,6 +891,13 @@ static struct mapped_device *alloc_dev(u
init_waitqueue_head(&md->wait);
init_waitqueue_head(&md->eventq);
+ /* Populate the mapping, nobody knows we exist yet */
+ mutex_lock(&_minor_lock);
+ old_md = idr_replace(&_minor_idr, md, minor);
+ mutex_unlock(&_minor_lock);
+
+ BUG_ON(old_md != MINOR_ALLOCED);
+
return md;
bad4:
@@ -1018,7 +1028,7 @@ static struct mapped_device *dm_find_md(
mutex_lock(&_minor_lock);
md = idr_find(&_minor_idr, minor);
- if (!md || (dm_disk(md)->first_minor != minor))
+ if (md && (md == MINOR_ALLOCED || (dm_disk(md)->first_minor != minor)))
md = NULL;
mutex_unlock(&_minor_lock);
@@ -1057,6 +1067,9 @@ void dm_put(struct mapped_device *md)
if (atomic_dec_and_test(&md->holders)) {
map = dm_get_table(md);
+ mutex_lock(&_minor_lock);
+ idr_replace(&_minor_idr, MINOR_ALLOCED, dm_disk(md)->first_minor);
+ mutex_unlock(&_minor_lock);
if (!dm_suspended(md)) {
dm_table_presuspend_targets(map);
dm_table_postsuspend_targets(map);
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
