Reduce number of undocumented barriers out there.
Signed-off-by: David Sterba <dsterba@xxxxxxx>
---
fs/btrfs/compression.c | 3 +++
fs/btrfs/extent-tree.c | 3 +--
fs/btrfs/locking.c | 3 +++
fs/btrfs/ordered-data.c | 6 ++++++
fs/btrfs/transaction.c | 3 +++
5 files changed, 16 insertions(+), 2 deletions(-)
diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index e9df8862012c..38ffb5526b1b 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -838,6 +838,9 @@ static void free_workspace(int type, struct list_head *workspace)
btrfs_compress_op[idx]->free_workspace(workspace);
atomic_dec(alloc_workspace);
wake:
+ /*
+ * Make sure counter is updated before we wake up waiters.
+ */
smp_mb();
if (waitqueue_active(workspace_wait))
wake_up(workspace_wait);
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 28ce5c8004d4..46ca10ab243f 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -9732,8 +9732,7 @@ void btrfs_end_write_no_snapshoting(struct btrfs_root *root)
{
percpu_counter_dec(&root->subv_writers->counter);
/*
- * Make sure counter is updated before we wake up
- * waiters.
+ * Make sure counter is updated before we wake up waiters.
*/
smp_mb();
if (waitqueue_active(&root->subv_writers->wait))
diff --git a/fs/btrfs/locking.c b/fs/btrfs/locking.c
index f8229ef1b46d..ec69baf28692 100644
--- a/fs/btrfs/locking.c
+++ b/fs/btrfs/locking.c
@@ -279,6 +279,9 @@ void btrfs_tree_unlock(struct extent_buffer *eb)
if (blockers) {
WARN_ON(atomic_read(&eb->spinning_writers));
atomic_dec(&eb->blocking_writers);
+ /*
+ * Make sure counter is updated before we wake up waiters.
+ */
smp_mb();
if (waitqueue_active(&eb->write_lock_wq))
wake_up(&eb->write_lock_wq);
diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c
index 534544e08f76..09dc73e7df7b 100644
--- a/fs/btrfs/ordered-data.c
+++ b/fs/btrfs/ordered-data.c
@@ -352,6 +352,9 @@ int btrfs_dec_test_first_ordered_pending(struct inode *inode,
if (entry->bytes_left == 0) {
ret = test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
+ /*
+ * Implicit memory barrier after test_and_set_bit
+ */
if (waitqueue_active(&entry->wait))
wake_up(&entry->wait);
} else {
@@ -416,6 +419,9 @@ have_entry:
if (entry->bytes_left == 0) {
ret = test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
+ /*
+ * Implicit memory barrier after test_and_set_bit
+ */
if (waitqueue_active(&entry->wait))
wake_up(&entry->wait);
} else {
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 90ba0c3c3d0d..6302939345a8 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -814,6 +814,9 @@ static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
atomic_dec(&cur_trans->num_writers);
extwriter_counter_dec(cur_trans, trans->type);
+ /*
+ * Make sure counter is updated before we wake up waiters.
+ */
smp_mb();
if (waitqueue_active(&cur_trans->writer_wait))
wake_up(&cur_trans->writer_wait);
--
1.8.4.5
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