[PATCH 06/24] xfs: call xfs_buf_iodone directly

Dave Chinner
2020-05-22T03:50:40Z

From: Dave Chinner <dchinner@redhat.com>

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 <dchinner@redhat.com>
---
fs/xfs/xfs_buf.c | 24 +++++++++---------------
fs/xfs/xfs_buf.h | 6 +-----
fs/xfs/xfs_buf_item.c | 38 +++++++++-----------------------------
fs/xfs/xfs_buf_item.h | 2 +-
fs/xfs/xfs_trans_buf.c | 9 +--------
5 files changed, 21 insertions(+), 58 deletions(-)

diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index b89685ce8519d..5fc83637f7aff 100644
--- a/fs/xfs/xfs_buf.c
+++ b/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;
}
@@ -1194,10 +1193,13 @@ 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) {
@@ -1205,9 +1207,6 @@ xfs_buf_ioend(
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.
@@ -1229,13 +1228,8 @@ xfs_buf_ioend(
return;
}

- if (bp->b_iodone) {
- (*(bp->b_iodone))(bp);
- return;
- }
-
-out_finish:
- xfs_buf_ioend_finish(bp);
+ /* dirty buffers always need to be removed from the AIL */
+ xfs_buf_dirty_iodone(bp);
}

static void
diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h
index c5fe4c48c9080..a127d56d5eff0 100644
--- a/fs/xfs/xfs_buf.h
+++ b/fs/xfs/xfs_buf.h
@@ -18,6 +18,7 @@
/*
* Base types
*/
+struct xfs_buf;

#define XFS_BUF_DADDR_NULL ((xfs_daddr_t) (-1LL))

@@ -103,10 +104,6 @@ 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 {
@@ -159,7 +156,6 @@ 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 */
diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c
index a42cdf9ccc47d..c2e7d14e35c66 100644
--- a/fs/xfs/xfs_buf_item.c
+++ b/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(
@@ -952,9 +947,6 @@ 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);
}
@@ -962,10 +954,7 @@ xfs_buf_item_relse(

/*
* 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);

@@ -1182,28 +1166,24 @@ 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);
@@ -1211,10 +1191,10 @@ xfs_buf_inode_iodone(
}

/*
- * Dquot buffer iodone callback function.
+ * Dirty buffer iodone callback function.
*/
void
-xfs_buf_dquot_iodone(
+xfs_buf_dirty_iodone(
struct xfs_buf *bp)
{
xfs_buf_run_callbacks(bp);
diff --git a/fs/xfs/xfs_buf_item.h b/fs/xfs/xfs_buf_item.h
index 27d13d29b5bbb..96f994ec90915 100644
--- a/fs/xfs/xfs_buf_item.h
+++ b/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_inode_iodone(struct xfs_buf *);
void xfs_buf_dquot_iodone(struct xfs_buf *);
+void xfs_buf_dirty_iodone(struct xfs_buf *);
bool xfs_buf_log_check_iovec(struct xfs_log_iovec *iovec);

extern kmem_zone_t *xfs_buf_item_zone;
diff --git a/fs/xfs/xfs_trans_buf.c b/fs/xfs/xfs_trans_buf.c
index 93d62cb864c15..69e0ebe94a915 100644
--- a/fs/xfs/xfs_trans_buf.c
+++ b/fs/xfs/xfs_trans_buf.c
@@ -465,23 +465,16 @@ 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;

/*
--
2.26.2.761.g0e0b3e54be