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md/bitmap: remove rcu annotation from pointer arithmetic. 

Evaluating  "&mddev->disks" is simple pointer arithmetic, so
it does not need 'rcu' annotations - no dereferencing is happening.

Also enhance the comment to explain that 'rdev' in that case
is not actually a pointer to an rdev.

Reported-by: Patrick Marlier <patrick.marlier@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>
This commit is contained in:
NeilBrown 2015-05-20 15:05:09 +10:00
parent a81157768a
commit 8532e34390
1 changed files with 6 additions and 1 deletions
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7
drivers/md/bitmap.c
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@ -177,11 +177,16 @@ static struct md_rdev *next_active_rdev(struct md_rdev *rdev, struct mddev *mdde
* nr_pending is 0 and In_sync is clear, the entries we return will
* still be in the same position on the list when we re-enter
* list_for_each_entry_continue_rcu.
*
* Note that if entered with 'rdev == NULL' to start at the
* beginning, we temporarily assign 'rdev' to an address which
* isn't really an rdev, but which can be used by
* list_for_each_entry_continue_rcu() to find the first entry.
*/
rcu_read_lock();
if (rdev == NULL)
/* start at the beginning */
rdev = list_entry_rcu(&mddev->disks, struct md_rdev, same_set);
rdev = list_entry(&mddev->disks, struct md_rdev, same_set);
else {
/* release the previous rdev and start from there. */
rdev_dec_pending(rdev, mddev);