xfs: call xfs_buf_iodone directly

All unmarked dirty buffers should be in the AIL and have log items
attached to them. Hence when they are written, we will run a
callback to remove the item from the AIL if appropriate. Now that
we've handled inode and dquot buffers, all remaining calls are to
xfs_buf_iodone() and so we can hard code this rather than use an
indirect call.

Signed-off-by: Dave Chinner <[email protected]>
Reviewed-by: Darrick J. Wong <[email protected]>
Reviewed-by: Amir Goldstein <[email protected]>
Reviewed-by: Brian Foster <[email protected]>
Signed-off-by: Darrick J. Wong <[email protected]>

fs/xfs/xfs_buf.c

@@ -658,7 +658,6 @@ xfs_buf_find(
  */
  if (bp->b_flags & XBF_STALE) {
  ASSERT((bp->b_flags & _XBF_DELWRI_Q) == 0);
- ASSERT(bp->b_iodone == NULL);
  bp->b_flags &= _XBF_KMEM | _XBF_PAGES;
  bp->b_ops = NULL;
  }
@@ -1194,20 +1193,20 @@ xfs_buf_ioend(
  if (!bp->b_error && bp->b_io_error)
  xfs_buf_ioerror(bp, bp->b_io_error);
 
- /* Only validate buffers that were read without errors */
- if (read && !bp->b_error && bp->b_ops) {
- ASSERT(!bp->b_iodone);
- bp->b_ops->verify_read(bp);
+ if (read) {
+ if (!bp->b_error && bp->b_ops)
+ bp->b_ops->verify_read(bp);
+ if (!bp->b_error)
+ bp->b_flags |= XBF_DONE;
+ xfs_buf_ioend_finish(bp);
+ return;
  }
 
  if (!bp->b_error) {
  bp->b_flags &= ~XBF_WRITE_FAIL;
  bp->b_flags |= XBF_DONE;
  }
 
- if (read)
- goto out_finish;
-
  /*
  * If this is a log recovery buffer, we aren't doing transactional IO
  * yet so we need to let it handle IO completions.
@@ -1226,14 +1225,7 @@ xfs_buf_ioend(
  xfs_buf_dquot_iodone(bp);
  return;
  }
-
- if (bp->b_iodone) {
- (*(bp->b_iodone))(bp);
- return;
- }
-
-out_finish:
- xfs_buf_ioend_finish(bp);
+ xfs_buf_iodone(bp);
 }
 
 static void

fs/xfs/xfs_buf.h

@@ -18,6 +18,7 @@
 /*
  * Base types
  */
+struct xfs_buf;
 
 #define XFS_BUF_DADDR_NULL ((xfs_daddr_t) (-1LL))
 
@@ -102,10 +103,6 @@ typedef struct xfs_buftarg {
  struct ratelimit_state bt_ioerror_rl;
 } xfs_buftarg_t;
 
-struct xfs_buf;
-typedef void (*xfs_buf_iodone_t)(struct xfs_buf *);
-
-
 #define XB_PAGES 2
 
 struct xfs_buf_map {
@@ -158,7 +155,6 @@ typedef struct xfs_buf {
  xfs_buftarg_t *b_target; /* buffer target (device) */
  void *b_addr; /* virtual address of buffer */
  struct work_struct b_ioend_work;
- xfs_buf_iodone_t b_iodone; /* I/O completion function */
  struct completion b_iowait; /* queue for I/O waiters */
  struct xfs_buf_log_item *b_log_item;
  struct list_head b_li_list; /* Log items list head */

fs/xfs/xfs_buf_item.c

@@ -460,7 +460,6 @@ xfs_buf_item_unpin(
  xfs_buf_do_callbacks(bp);
  bp->b_log_item = NULL;
  list_del_init(&bp->b_li_list);
- bp->b_iodone = NULL;
  } else {
  xfs_trans_ail_delete(lip, SHUTDOWN_LOG_IO_ERROR);
  xfs_buf_item_relse(bp);
@@ -936,11 +935,7 @@ xfs_buf_item_free(
 }
 
 /*
- * This is called when the buf log item is no longer needed. It should
- * free the buf log item associated with the given buffer and clear
- * the buffer's pointer to the buf log item. If there are no more
- * items in the list, clear the b_iodone field of the buffer (see
- * xfs_buf_attach_iodone() below).
+ * xfs_buf_item_relse() is called when the buf log item is no longer needed.
  */
 void
 xfs_buf_item_relse(
@@ -952,20 +947,14 @@ xfs_buf_item_relse(
  ASSERT(!test_bit(XFS_LI_IN_AIL, &bip->bli_item.li_flags));
 
  bp->b_log_item = NULL;
- if (list_empty(&bp->b_li_list))
- bp->b_iodone = NULL;
-
  xfs_buf_rele(bp);
  xfs_buf_item_free(bip);
 }
 
 
 /*
  * Add the given log item with its callback to the list of callbacks
- * to be called when the buffer's I/O completes. If it is not set
- * already, set the buffer's b_iodone() routine to be
- * xfs_buf_iodone_callbacks() and link the log item into the list of
- * items rooted at b_li_list.
+ * to be called when the buffer's I/O completes.
  */
 void
 xfs_buf_attach_iodone(
@@ -977,10 +966,6 @@ xfs_buf_attach_iodone(
 
  lip->li_cb = cb;
  list_add_tail(&lip->li_bio_list, &bp->b_li_list);
-
- ASSERT(bp->b_iodone == NULL ||
- bp->b_iodone == xfs_buf_iodone_callbacks);
- bp->b_iodone = xfs_buf_iodone_callbacks;
 }
 
 /*
@@ -1096,7 +1081,6 @@ xfs_buf_iodone_callback_error(
  goto out_stale;
 
  trace_xfs_buf_item_iodone_async(bp, _RET_IP_);
- ASSERT(bp->b_iodone != NULL);
 
  cfg = xfs_error_get_cfg(mp, XFS_ERR_METADATA, bp->b_error);
 
@@ -1182,39 +1166,35 @@ xfs_buf_run_callbacks(
  xfs_buf_do_callbacks(bp);
  bp->b_log_item = NULL;
  list_del_init(&bp->b_li_list);
- bp->b_iodone = NULL;
 }
 
 /*
- * This is the iodone() function for buffers which have had callbacks attached
- * to them by xfs_buf_attach_iodone(). We need to iterate the items on the
- * callback list, mark the buffer as having no more callbacks and then push the
- * buffer through IO completion processing.
+ * Inode buffer iodone callback function.
  */
 void
-xfs_buf_iodone_callbacks(
+xfs_buf_inode_iodone(
  struct xfs_buf *bp)
 {
  xfs_buf_run_callbacks(bp);
- xfs_buf_ioend(bp);
+ xfs_buf_ioend_finish(bp);
 }
 
 /*
- * Inode buffer iodone callback function.
+ * Dquot buffer iodone callback function.
  */
 void
-xfs_buf_inode_iodone(
+xfs_buf_dquot_iodone(
  struct xfs_buf *bp)
 {
  xfs_buf_run_callbacks(bp);
  xfs_buf_ioend_finish(bp);
 }
 
 /*
- * Dquot buffer iodone callback function.
+ * Dirty buffer iodone callback function.
  */
 void
-xfs_buf_dquot_iodone(
+xfs_buf_iodone(
  struct xfs_buf *bp)
 {
  xfs_buf_run_callbacks(bp);
@@ -1229,7 +1209,7 @@ xfs_buf_dquot_iodone(
  * care of cleaning up the buffer itself.
  */
 void
-xfs_buf_iodone(
+xfs_buf_item_iodone(
  struct xfs_buf *bp,
  struct xfs_log_item *lip)
 {

fs/xfs/xfs_buf_item.h

@@ -57,10 +57,10 @@ bool xfs_buf_item_dirty_format(struct xfs_buf_log_item *);
 void xfs_buf_attach_iodone(struct xfs_buf *,
  void(*)(struct xfs_buf *, struct xfs_log_item *),
  struct xfs_log_item *);
-void xfs_buf_iodone_callbacks(struct xfs_buf *);
-void xfs_buf_iodone(struct xfs_buf *, struct xfs_log_item *);
+void xfs_buf_item_iodone(struct xfs_buf *, struct xfs_log_item *);
 void xfs_buf_inode_iodone(struct xfs_buf *);
 void xfs_buf_dquot_iodone(struct xfs_buf *);
+void xfs_buf_iodone(struct xfs_buf *);
 bool xfs_buf_log_check_iovec(struct xfs_log_iovec *iovec);
 
 extern kmem_zone_t *xfs_buf_item_zone;

fs/xfs/xfs_trans_buf.c

@@ -465,24 +465,17 @@ xfs_trans_dirty_buf(
 
  ASSERT(bp->b_transp == tp);
  ASSERT(bip != NULL);
- ASSERT(bp->b_iodone == NULL ||
- bp->b_iodone == xfs_buf_iodone_callbacks);
 
  /*
  * Mark the buffer as needing to be written out eventually,
  * and set its iodone function to remove the buffer's buf log
  * item from the AIL and free it when the buffer is flushed
- * to disk. See xfs_buf_attach_iodone() for more details
- * on li_cb and xfs_buf_iodone_callbacks().
- * If we end up aborting this transaction, we trap this buffer
- * inside the b_bdstrat callback so that this won't get written to
- * disk.
+ * to disk.
  */
  bp->b_flags |= XBF_DONE;
 
  ASSERT(atomic_read(&bip->bli_refcount) > 0);
- bp->b_iodone = xfs_buf_iodone_callbacks;
- bip->bli_item.li_cb = xfs_buf_iodone;
+ bip->bli_item.li_cb = xfs_buf_item_iodone;
 
  /*
  * If we invalidated the buffer within this transaction, then
@@ -651,7 +644,7 @@ xfs_trans_stale_inode_buf(
  ASSERT(atomic_read(&bip->bli_refcount) > 0);
 
  bip->bli_flags |= XFS_BLI_STALE_INODE;
- bip->bli_item.li_cb = xfs_buf_iodone;
+ bip->bli_item.li_cb = xfs_buf_item_iodone;
  bp->b_flags |= _XBF_INODES;
  xfs_trans_buf_set_type(tp, bp, XFS_BLFT_DINO_BUF);
 }