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Subject[PATCH] afs: Add missing memory barriers in afs_manage_cell()
Date
As the comments for wake_up_bit() and waitqueue_active() point out,
the barriers are needed to order the clearing of the _FL_NOT_READY
bit and the waitqueue_active() load; match the implicit barrier in
prepare_to_wait().

Signed-off-by: Andrea Parri <andrea.parri@amarulasolutions.com>
---
fs/afs/cell.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/fs/afs/cell.c b/fs/afs/cell.c
index cf445dbd5f2e0..a9488abe56029 100644
--- a/fs/afs/cell.c
+++ b/fs/afs/cell.c
@@ -637,6 +637,7 @@ static void afs_manage_cell(struct work_struct *work)
cell->state = AFS_CELL_ACTIVE;
smp_wmb();
clear_bit(AFS_CELL_FL_NOT_READY, &cell->flags);
+ smp_mb__after_atomic(); /* see comment for wake_up_bit() */
wake_up_bit(&cell->flags, AFS_CELL_FL_NOT_READY);
goto again;

@@ -678,6 +679,7 @@ static void afs_manage_cell(struct work_struct *work)
cell->state = AFS_CELL_ACTIVE;
smp_wmb();
clear_bit(AFS_CELL_FL_NOT_READY, &cell->flags);
+ smp_mb__after_atomic(); /* see comment for wake_up_bit() */
wake_up_bit(&cell->flags, AFS_CELL_FL_NOT_READY);
_leave(" [deact->act]");
return;
--
2.17.1
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