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btrfs: split btrfs_set_lock_blocking_rw to read and write helpers

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There are many callers that hardcode the desired lock type so we can
avoid the switch and call them directly. Split the current function to
two but leave a helper that still takes the variable lock type to make
current code compile.  The call sites will be converted in followup
patches.

Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
David Sterba 2018-04-04 01:43:05 +02:00
parent 9627736b75
commit b95be2d9fb
2 changed files with 40 additions and 25 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

50
fs/btrfs/locking.c
View File

@ -14,35 +14,37 @@
static void btrfs_assert_tree_read_locked(struct extent_buffer *eb);
/*
* if we currently have a spinning reader or writer lock
* (indicated by the rw flag) this will bump the count
* of blocking holders and drop the spinlock.
*/
void btrfs_set_lock_blocking_rw(struct extent_buffer *eb, int rw)
void btrfs_set_lock_blocking_read(struct extent_buffer *eb)
{
/*
* no lock is required. The lock owner may change if
* we have a read lock, but it won't change to or away
* from us. If we have the write lock, we are the owner
* and it'll never change.
* No lock is required. The lock owner may change if we have a read
* lock, but it won't change to or away from us. If we have the write
* lock, we are the owner and it'll never change.
*/
if (eb->lock_nested && current->pid == eb->lock_owner)
return;
if (rw == BTRFS_WRITE_LOCK) {
if (atomic_read(&eb->blocking_writers) == 0) {
WARN_ON(atomic_read(&eb->spinning_writers) != 1);
atomic_dec(&eb->spinning_writers);
btrfs_assert_tree_locked(eb);
atomic_inc(&eb->blocking_writers);
write_unlock(&eb->lock);
}
} else if (rw == BTRFS_READ_LOCK) {
btrfs_assert_tree_read_locked(eb);
atomic_inc(&eb->blocking_readers);
WARN_ON(atomic_read(&eb->spinning_readers) == 0);
atomic_dec(&eb->spinning_readers);
read_unlock(&eb->lock);
btrfs_assert_tree_read_locked(eb);
atomic_inc(&eb->blocking_readers);
WARN_ON(atomic_read(&eb->spinning_readers) == 0);
atomic_dec(&eb->spinning_readers);
read_unlock(&eb->lock);
}
void btrfs_set_lock_blocking_write(struct extent_buffer *eb)
{
/*
* No lock is required. The lock owner may change if we have a read
* lock, but it won't change to or away from us. If we have the write
* lock, we are the owner and it'll never change.
*/
if (eb->lock_nested && current->pid == eb->lock_owner)
return;
if (atomic_read(&eb->blocking_writers) == 0) {
WARN_ON(atomic_read(&eb->spinning_writers) != 1);
atomic_dec(&eb->spinning_writers);
btrfs_assert_tree_locked(eb);
atomic_inc(&eb->blocking_writers);
write_unlock(&eb->lock);
}
}

15
fs/btrfs/locking.h
View File

@ -17,7 +17,8 @@ void btrfs_tree_unlock(struct extent_buffer *eb);
void btrfs_tree_read_lock(struct extent_buffer *eb);
void btrfs_tree_read_unlock(struct extent_buffer *eb);
void btrfs_tree_read_unlock_blocking(struct extent_buffer *eb);
void btrfs_set_lock_blocking_rw(struct extent_buffer *eb, int rw);
void btrfs_set_lock_blocking_read(struct extent_buffer *eb);
void btrfs_set_lock_blocking_write(struct extent_buffer *eb);
void btrfs_clear_lock_blocking_rw(struct extent_buffer *eb, int rw);
void btrfs_assert_tree_locked(struct extent_buffer *eb);
int btrfs_try_tree_read_lock(struct extent_buffer *eb);
@ -37,6 +38,18 @@ static inline void btrfs_tree_unlock_rw(struct extent_buffer *eb, int rw)
BUG();
}
/*
* If we currently have a spinning reader or writer lock (indicated by the rw
* flag) this will bump the count of blocking holders and drop the spinlock.
*/
static inline void btrfs_set_lock_blocking_rw(struct extent_buffer *eb, int rw)
{
if (rw == BTRFS_WRITE_LOCK)
btrfs_set_lock_blocking_write(eb);
else if (rw == BTRFS_READ_LOCK)
btrfs_set_lock_blocking_read(eb);
}
static inline void btrfs_set_lock_blocking(struct extent_buffer *eb)
{
btrfs_set_lock_blocking_rw(eb, BTRFS_WRITE_LOCK);