[PATCH 07/10] netfs: Fix missing barriers by using clear_and_wake_up_bit()

David Howells
2024-12-13T13:51:19Z

Use clear_and_wake_up_bit() rather than something like:

clear_bit_unlock(NETFS_RREQ_IN_PROGRESS, &rreq->flags);
wake_up_bit(&rreq->flags, NETFS_RREQ_IN_PROGRESS);

as there needs to be a barrier inserted between which is present in
clear_and_wake_up_bit().

Fixes: 288ace2f57c9 ("netfs: New writeback implementation")
Fixes: ee4cdf7ba857 ("netfs: Speed up buffered reading")
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Zilin Guan <zilin@seu.edu.cn>
cc: Akira Yokosawa <akiyks@gmail.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
---
fs/netfs/read_collect.c | 3 +--
fs/netfs/write_collect.c | 9 +++------
2 files changed, 4 insertions(+), 8 deletions(-)

diff --git a/fs/netfs/read_collect.c b/fs/netfs/read_collect.c
index b415e3972336..46ce3b7adf07 100644
--- a/fs/netfs/read_collect.c
+++ b/fs/netfs/read_collect.c
@@ -379,8 +379,7 @@ static void netfs_rreq_assess(struct netfs_io_request *rreq)
task_io_account_read(rreq->transferred);

trace_netfs_rreq(rreq, netfs_rreq_trace_wake_ip);
- clear_bit_unlock(NETFS_RREQ_IN_PROGRESS, &rreq->flags);
- wake_up_bit(&rreq->flags, NETFS_RREQ_IN_PROGRESS);
+ clear_and_wake_up_bit(NETFS_RREQ_IN_PROGRESS, &rreq->flags);

trace_netfs_rreq(rreq, netfs_rreq_trace_done);
netfs_clear_subrequests(rreq, false);
diff --git a/fs/netfs/write_collect.c b/fs/netfs/write_collect.c
index 1d438be2e1b4..82290c92ba7a 100644
--- a/fs/netfs/write_collect.c
+++ b/fs/netfs/write_collect.c
@@ -501,8 +501,7 @@ static void netfs_collect_write_results(struct netfs_io_request *wreq)
goto need_retry;
if ((notes & MADE_PROGRESS) && test_bit(NETFS_RREQ_PAUSE, &wreq->flags)) {
trace_netfs_rreq(wreq, netfs_rreq_trace_unpause);
- clear_bit_unlock(NETFS_RREQ_PAUSE, &wreq->flags);
- wake_up_bit(&wreq->flags, NETFS_RREQ_PAUSE);
+ clear_and_wake_up_bit(NETFS_RREQ_PAUSE, &wreq->flags);
}

if (notes & NEED_REASSESS) {
@@ -605,8 +604,7 @@ void netfs_write_collection_worker(struct work_struct *work)

_debug("finished");
trace_netfs_rreq(wreq, netfs_rreq_trace_wake_ip);
- clear_bit_unlock(NETFS_RREQ_IN_PROGRESS, &wreq->flags);
- wake_up_bit(&wreq->flags, NETFS_RREQ_IN_PROGRESS);
+ clear_and_wake_up_bit(NETFS_RREQ_IN_PROGRESS, &wreq->flags);

if (wreq->iocb) {
size_t written = min(wreq->transferred, wreq->len);
@@ -714,8 +712,7 @@ void netfs_write_subrequest_terminated(void *_op, ssize_t transferred_or_error,

trace_netfs_sreq(subreq, netfs_sreq_trace_terminated);

- clear_bit_unlock(NETFS_SREQ_IN_PROGRESS, &subreq->flags);
- wake_up_bit(&subreq->flags, NETFS_SREQ_IN_PROGRESS);
+ clear_and_wake_up_bit(NETFS_SREQ_IN_PROGRESS, &subreq->flags);

/* If we are at the head of the queue, wake up the collector,
* transferring a ref to it if we were the ones to do so.