[PATCH 31/34] xfs: convert log grant heads to atomic variables

Dave Chinner
2010-12-21T07:28:43Z

Convert the log grant heads to atomic64_t types in preparation for
converting the accounting algorithms to atomic operations. his patch
just converts the variables; the algorithmic changes are in a
separate patch for clarity.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
fs/xfs/xfs_log.c | 8 ++++----
fs/xfs/xfs_log_priv.h | 12 ++++++------
2 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index d118bf8..a1d7d12 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -47,7 +47,7 @@ STATIC xlog_t * xlog_alloc_log(xfs_mount_t *mp,
xfs_buftarg_t *log_target,
xfs_daddr_t blk_offset,
int num_bblks);
-STATIC int xlog_space_left(struct log *log, int64_t *head);
+STATIC int xlog_space_left(struct log *log, atomic64_t *head);
STATIC int xlog_sync(xlog_t *log, xlog_in_core_t *iclog);
STATIC void xlog_dealloc_log(xlog_t *log);

@@ -100,7 +100,7 @@ STATIC int xlog_iclogs_empty(xlog_t *log);
static void
xlog_grant_sub_space(
struct log *log,
- int64_t *head,
+ atomic64_t *head,
int bytes)
{
int cycle, space;
@@ -119,7 +119,7 @@ xlog_grant_sub_space(
static void
xlog_grant_add_space(
struct log *log,
- int64_t *head,
+ atomic64_t *head,
int bytes)
{
int tmp;
@@ -816,7 +816,7 @@ xlog_assign_tail_lsn(
STATIC int
xlog_space_left(
struct log *log,
- int64_t *head)
+ atomic64_t *head)
{
int free_bytes;
int tail_bytes;
diff --git a/fs/xfs/xfs_log_priv.h b/fs/xfs/xfs_log_priv.h
index d34af1c..7619d6a 100644
--- a/fs/xfs/xfs_log_priv.h
+++ b/fs/xfs/xfs_log_priv.h
@@ -514,8 +514,8 @@ typedef struct log {
spinlock_t l_grant_lock ____cacheline_aligned_in_smp;
struct list_head l_reserveq;
struct list_head l_writeq;
- int64_t l_grant_reserve_head;
- int64_t l_grant_write_head;
+ atomic64_t l_grant_reserve_head;
+ atomic64_t l_grant_write_head;

/*
* l_last_sync_lsn and l_tail_lsn are atomics so they can be set and
@@ -596,18 +596,18 @@ xlog_assign_atomic_lsn(atomic64_t *lsn, uint cycle, uint block)
* will always get consistent component values to work from.
*/
static inline void
-xlog_crack_grant_head(int64_t *head, int *cycle, int *space)
+xlog_crack_grant_head(atomic64_t *head, int *cycle, int *space)
{
- int64_t val = *head;
+ int64_t val = atomic64_read(head);

*cycle = val >> 32;
*space = val & 0xffffffff;
}

static inline void
-xlog_assign_grant_head(int64_t *head, int cycle, int space)
+xlog_assign_grant_head(atomic64_t *head, int cycle, int space)
{
- *head = ((int64_t)cycle << 32) | space;
+ atomic64_set(head, ((int64_t)cycle << 32) | space);