xfs: combine [a]sync buffer submission apis
The buffer I/O submission path consists of separate function calls
per type. The buffer I/O type is already controlled via buffer
state (XBF_ASYNC), however, so there is no real need for separate
submission functions.
Combine the buffer submission functions into a single function that
processes the buffer appropriately based on XBF_ASYNC. Retain an
internal helper with a conditional wait parameter to continue to
support batched !XBF_ASYNC submission/completion required by delwri
queues.
Suggested-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index ef23484..be79dd2 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -757,11 +757,7 @@ _xfs_buf_read(
bp->b_flags &= ~(XBF_WRITE | XBF_ASYNC | XBF_READ_AHEAD);
bp->b_flags |= flags & (XBF_READ | XBF_ASYNC | XBF_READ_AHEAD);
- if (flags & XBF_ASYNC) {
- xfs_buf_submit(bp);
- return 0;
- }
- return xfs_buf_submit_wait(bp);
+ return xfs_buf_submit(bp);
}
xfs_buf_t *
@@ -846,7 +842,7 @@ xfs_buf_read_uncached(
bp->b_flags |= XBF_READ;
bp->b_ops = ops;
- xfs_buf_submit_wait(bp);
+ xfs_buf_submit(bp);
if (bp->b_error) {
int error = bp->b_error;
xfs_buf_relse(bp);
@@ -1249,7 +1245,7 @@ xfs_bwrite(
bp->b_flags &= ~(XBF_ASYNC | XBF_READ | _XBF_DELWRI_Q |
XBF_WRITE_FAIL | XBF_DONE);
- error = xfs_buf_submit_wait(bp);
+ error = xfs_buf_submit(bp);
if (error) {
xfs_force_shutdown(bp->b_target->bt_mount,
SHUTDOWN_META_IO_ERROR);
@@ -1459,7 +1455,7 @@ _xfs_buf_ioapply(
* itself.
*/
static int
-__xfs_buf_submit(
+__xfs_buf_submit_common(
struct xfs_buf *bp)
{
trace_xfs_buf_submit(bp, _RET_IP_);
@@ -1505,32 +1501,6 @@ __xfs_buf_submit(
return 0;
}
-void
-xfs_buf_submit(
- struct xfs_buf *bp)
-{
- int error;
-
- ASSERT(bp->b_flags & XBF_ASYNC);
-
- /*
- * The caller's reference is released during I/O completion.
- * This occurs some time after the last b_io_remaining reference is
- * released, so after we drop our Io reference we have to have some
- * other reference to ensure the buffer doesn't go away from underneath
- * us. Take a direct reference to ensure we have safe access to the
- * buffer until we are finished with it.
- */
- xfs_buf_hold(bp);
-
- error = __xfs_buf_submit(bp);
- if (error)
- xfs_buf_ioend(bp);
-
- /* Note: it is not safe to reference bp now we've dropped our ref */
- xfs_buf_rele(bp);
-}
-
/*
* Wait for I/O completion of a sync buffer and return the I/O error code.
*/
@@ -1538,6 +1508,8 @@ static int
xfs_buf_iowait(
struct xfs_buf *bp)
{
+ ASSERT(!(bp->b_flags & XBF_ASYNC));
+
trace_xfs_buf_iowait(bp, _RET_IP_);
wait_for_completion(&bp->b_iowait);
trace_xfs_buf_iowait_done(bp, _RET_IP_);
@@ -1549,30 +1521,33 @@ xfs_buf_iowait(
* Synchronous buffer IO submission path, read or write.
*/
int
-xfs_buf_submit_wait(
- struct xfs_buf *bp)
+__xfs_buf_submit(
+ struct xfs_buf *bp,
+ bool wait)
{
int error;
- ASSERT(!(bp->b_flags & XBF_ASYNC));
-
/*
- * For synchronous IO, the IO does not inherit the submitters reference
- * count, nor the buffer lock. Hence we cannot release the reference we
- * are about to take until we've waited for all IO completion to occur,
- * including any xfs_buf_ioend_async() work that may be pending.
+ * Grab a reference so the buffer does not go away underneath us. For
+ * async buffers, I/O completion drops the callers reference, which
+ * could occur before submission returns.
*/
xfs_buf_hold(bp);
- error = __xfs_buf_submit(bp);
- if (error)
+ error = __xfs_buf_submit_common(bp);
+ if (error) {
+ if (bp->b_flags & XBF_ASYNC)
+ xfs_buf_ioend(bp);
goto out;
- error = xfs_buf_iowait(bp);
+ }
+ if (wait)
+ error = xfs_buf_iowait(bp);
out:
/*
- * all done now, we can release the hold that keeps the buffer
- * referenced for the entire IO.
+ * Release the hold that keeps the buffer referenced for the entire
+ * I/O. Note that if the buffer is async, it is not safe to reference
+ * after this release.
*/
xfs_buf_rele(bp);
return error;
@@ -2026,12 +2001,11 @@ xfs_buf_delwri_submit_buffers(
if (wait_list) {
bp->b_flags &= ~XBF_ASYNC;
list_move_tail(&bp->b_list, wait_list);
- __xfs_buf_submit(bp);
} else {
bp->b_flags |= XBF_ASYNC;
list_del_init(&bp->b_list);
- xfs_buf_submit(bp);
}
+ __xfs_buf_submit(bp, false);
}
blk_finish_plug(&plug);
