[PATCH 2/4] xfs: remove callback dequeue loop from xlog_state_do_iclog_callbacks
From: Dave Chinner <david@fromorbit.com>
Date: 2021-06-22 04:06:13
Subsystem:
filesystems (vfs and infrastructure), the rest, xfs filesystem · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds, Carlos Maiolino
From: Dave Chinner <redacted> If we are processing callbacks on an iclog, nothing can be concurrently adding callbacks to the loop. We only add callbacks to the iclog when they are in ACTIVE or WANT_SYNC state, and we explicitly do not add callbacks if the iclog is already in IOERROR state. The only way to have a dequeue racing with an enqueue is to be processing a shutdown without a direct reference to an iclog in ACTIVE or WANT_SYNC state. As the enqueue avoids this race condition, we only ever need a single dequeue operation in xlog_state_do_iclog_callbacks(). Hence we can remove the loop. Signed-off-by: Dave Chinner <redacted> --- fs/xfs/xfs_log.c | 16 ++++++---------- 1 file changed, 6 insertions(+), 10 deletions(-)
diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index bb4390942275..05b00fa4d661 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c@@ -2774,19 +2774,15 @@ xlog_state_do_iclog_callbacks( struct xlog *log, struct xlog_in_core *iclog) { - trace_xlog_iclog_callbacks_start(iclog, _RET_IP_); - spin_lock(&iclog->ic_callback_lock); - while (!list_empty(&iclog->ic_callbacks)) { - LIST_HEAD(tmp); + LIST_HEAD(tmp); - list_splice_init(&iclog->ic_callbacks, &tmp); - - spin_unlock(&iclog->ic_callback_lock); - xlog_cil_process_committed(&tmp); - spin_lock(&iclog->ic_callback_lock); - } + trace_xlog_iclog_callbacks_start(iclog, _RET_IP_); + spin_lock(&iclog->ic_callback_lock); + list_splice_init(&iclog->ic_callbacks, &tmp); spin_unlock(&iclog->ic_callback_lock); + + xlog_cil_process_committed(&tmp); trace_xlog_iclog_callbacks_done(iclog, _RET_IP_); }
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2.31.1