xfs: clean up buffer locking helpers

Rename xfs_buf_cond_lock and reverse it's return value to fit most other
trylock operations in the Kernel and XFS (with the exception of down_trylock,
after which xfs_buf_cond_lock was modelled), and replace xfs_buf_lock_val
with an xfs_buf_islocked for use in asserts, or and opencoded variant in
tracing.  remove the XFS_BUF_* wrappers for all the locking helpers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Alex Elder <aelder@sgi.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

3 files changed, 19 insertions, 31 deletions

diff --git a/fs/xfs/linux-2.6/xfs_buf.c b/fs/xfs/linux-2.6/xfs_buf.c
index 5e68099db2a5..c77227615403 100644
--- a/fs/xfs/linux-2.6/xfs_buf.c
+++ b/fs/xfs/linux-2.6/xfs_buf.c
@@ -499,16 +499,14 @@ found:
         spin_unlock(&pag->pag_buf_lock);
         xfs_perag_put(pag);
 
-        if (xfs_buf_cond_lock(bp)) {
-                /* failed, so wait for the lock if requested. */
-                if (!(flags & XBF_TRYLOCK)) {
-                        xfs_buf_lock(bp);
-                        XFS_STATS_INC(xb_get_locked_waited);
-                } else {
+        if (!xfs_buf_trylock(bp)) {
+                if (flags & XBF_TRYLOCK) {
                         xfs_buf_rele(bp);
                         XFS_STATS_INC(xb_busy_locked);
                         return NULL;
                 }
+                xfs_buf_lock(bp);
+                XFS_STATS_INC(xb_get_locked_waited);
         }
 
         /*
@@ -896,8 +894,8 @@ xfs_buf_rele(
  *      to push on stale inode buffers.
  */
 int
-xfs_buf_cond_lock(
-        xfs_buf_t               *bp)
+xfs_buf_trylock(
+        struct xfs_buf          *bp)
 {
         int                     locked;
 
@@ -907,15 +905,8 @@ xfs_buf_cond_lock(
         else if (atomic_read(&bp->b_pin_count) && (bp->b_flags & XBF_STALE))
                 xfs_log_force(bp->b_target->bt_mount, 0);
 
-        trace_xfs_buf_cond_lock(bp, _RET_IP_);
-        return locked ? 0 : -EBUSY;
-}
-
-int
-xfs_buf_lock_value(
-        xfs_buf_t               *bp)
-{
-        return bp->b_sema.count;
+        trace_xfs_buf_trylock(bp, _RET_IP_);
+        return locked;
 }
 
 /*
@@ -929,7 +920,7 @@ xfs_buf_lock_value(
  */
 void
 xfs_buf_lock(
-        xfs_buf_t               *bp)
+        struct xfs_buf          *bp)
 {
         trace_xfs_buf_lock(bp, _RET_IP_);
 
@@ -950,7 +941,7 @@ xfs_buf_lock(
  */
 void
 xfs_buf_unlock(
-        xfs_buf_t               *bp)
+        struct xfs_buf          *bp)
 {
         if ((bp->b_flags & (XBF_DELWRI|_XBF_DELWRI_Q)) == XBF_DELWRI) {
                 atomic_inc(&bp->b_hold);
@@ -1694,7 +1685,7 @@ xfs_buf_delwri_split(
         list_for_each_entry_safe(bp, n, dwq, b_list) {
                 ASSERT(bp->b_flags & XBF_DELWRI);
 
-                if (!XFS_BUF_ISPINNED(bp) && !xfs_buf_cond_lock(bp)) {
+                if (!XFS_BUF_ISPINNED(bp) && xfs_buf_trylock(bp)) {
                         if (!force &&
                             time_before(jiffies, bp->b_queuetime + age)) {
                                 xfs_buf_unlock(bp);
diff --git a/fs/xfs/linux-2.6/xfs_buf.h b/fs/xfs/linux-2.6/xfs_buf.h
index 6847dc4dceeb..706c40069116 100644
--- a/fs/xfs/linux-2.6/xfs_buf.h
+++ b/fs/xfs/linux-2.6/xfs_buf.h
@@ -187,10 +187,11 @@ extern void xfs_buf_free(xfs_buf_t *);
 extern void xfs_buf_rele(xfs_buf_t *);
 
 /* Locking and Unlocking Buffers */
-extern int xfs_buf_cond_lock(xfs_buf_t *);
-extern int xfs_buf_lock_value(xfs_buf_t *);
+extern int xfs_buf_trylock(xfs_buf_t *);
 extern void xfs_buf_lock(xfs_buf_t *);
 extern void xfs_buf_unlock(xfs_buf_t *);
+#define xfs_buf_islocked(bp) \
+        ((bp)->b_sema.count <= 0)
 
 /* Buffer Read and Write Routines */
 extern int xfs_bwrite(struct xfs_mount *mp, struct xfs_buf *bp);
@@ -308,10 +309,6 @@ xfs_buf_set_ref(
 
 #define XFS_BUF_ISPINNED(bp)    atomic_read(&((bp)->b_pin_count))
 
-#define XFS_BUF_VALUSEMA(bp)    xfs_buf_lock_value(bp)
-#define XFS_BUF_CPSEMA(bp)      (xfs_buf_cond_lock(bp) == 0)
-#define XFS_BUF_VSEMA(bp)       xfs_buf_unlock(bp)
-#define XFS_BUF_PSEMA(bp,x)     xfs_buf_lock(bp)
 #define XFS_BUF_FINISH_IOWAIT(bp)       complete(&bp->b_iowait);
 
 #define XFS_BUF_SET_TARGET(bp, target)  ((bp)->b_target = (target))
diff --git a/fs/xfs/linux-2.6/xfs_trace.h b/fs/xfs/linux-2.6/xfs_trace.h
index 4fe53f9f0477..3bdfcb9f52b7 100644
--- a/fs/xfs/linux-2.6/xfs_trace.h
+++ b/fs/xfs/linux-2.6/xfs_trace.h
@@ -293,7 +293,7 @@ DECLARE_EVENT_CLASS(xfs_buf_class,
                 __entry->buffer_length = bp->b_buffer_length;
                 __entry->hold = atomic_read(&bp->b_hold);
                 __entry->pincount = atomic_read(&bp->b_pin_count);
-                __entry->lockval = xfs_buf_lock_value(bp);
+                __entry->lockval = bp->b_sema.count;
                 __entry->flags = bp->b_flags;
                 __entry->caller_ip = caller_ip;
         ),
@@ -323,7 +323,7 @@ DEFINE_BUF_EVENT(xfs_buf_bawrite);
 DEFINE_BUF_EVENT(xfs_buf_bdwrite);
 DEFINE_BUF_EVENT(xfs_buf_lock);
 DEFINE_BUF_EVENT(xfs_buf_lock_done);
-DEFINE_BUF_EVENT(xfs_buf_cond_lock);
+DEFINE_BUF_EVENT(xfs_buf_trylock);
 DEFINE_BUF_EVENT(xfs_buf_unlock);
 DEFINE_BUF_EVENT(xfs_buf_iowait);
 DEFINE_BUF_EVENT(xfs_buf_iowait_done);
@@ -366,7 +366,7 @@ DECLARE_EVENT_CLASS(xfs_buf_flags_class,
                 __entry->flags = flags;
                 __entry->hold = atomic_read(&bp->b_hold);
                 __entry->pincount = atomic_read(&bp->b_pin_count);
-                __entry->lockval = xfs_buf_lock_value(bp);
+                __entry->lockval = bp->b_sema.count;
                 __entry->caller_ip = caller_ip;
         ),
         TP_printk("dev %d:%d bno 0x%llx len 0x%zx hold %d pincount %d "
@@ -409,7 +409,7 @@ TRACE_EVENT(xfs_buf_ioerror,
                 __entry->buffer_length = bp->b_buffer_length;
                 __entry->hold = atomic_read(&bp->b_hold);
                 __entry->pincount = atomic_read(&bp->b_pin_count);
-                __entry->lockval = xfs_buf_lock_value(bp);
+                __entry->lockval = bp->b_sema.count;
                 __entry->error = error;
                 __entry->flags = bp->b_flags;
                 __entry->caller_ip = caller_ip;
@@ -454,7 +454,7 @@ DECLARE_EVENT_CLASS(xfs_buf_item_class,
                 __entry->buf_flags = bip->bli_buf->b_flags;
                 __entry->buf_hold = atomic_read(&bip->bli_buf->b_hold);
                 __entry->buf_pincount = atomic_read(&bip->bli_buf->b_pin_count);
-                __entry->buf_lockval = xfs_buf_lock_value(bip->bli_buf);
+                __entry->buf_lockval = bip->bli_buf->b_sema.count;
                 __entry->li_desc = bip->bli_item.li_desc;
                 __entry->li_flags = bip->bli_item.li_flags;
         ),