Unverified Commit 627cf645 authored by David Howells's avatar David Howells Committed by Christian Brauner
Browse files

netfs: Don't use bh spinlock 



All the accessing of the subrequest lists is now done in process context,
possibly in a workqueue, but not now in a BH context, so we don't need the
lock against BH interference when taking the netfs_io_request::lock
spinlock.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/20241216204124.3752367-11-dhowells@redhat.com


cc: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent 31fc366a

fs/netfs/buffered_read.c

+2 −2
Original line number Diff line number Diff line
@@ -200,12 +200,12 @@ static void netfs_read_to_pagecache(struct netfs_io_request *rreq) 
		subreq->len	= size;



		atomic_inc(&rreq->nr_outstanding);

		spin_lock_bh(&rreq->lock);

		spin_lock(&rreq->lock);

		list_add_tail(&subreq->rreq_link, &rreq->subrequests);

		subreq->prev_donated = rreq->prev_donated;

		rreq->prev_donated = 0;

		trace_netfs_sreq(subreq, netfs_sreq_trace_added);

		spin_unlock_bh(&rreq->lock);

		spin_unlock(&rreq->lock);



		source = netfs_cache_prepare_read(rreq, subreq, rreq->i_size);

		subreq->source = source;

fs/netfs/direct_read.c

+2 −2
Original line number Diff line number Diff line
@@ -68,12 +68,12 @@ static int netfs_dispatch_unbuffered_reads(struct netfs_io_request *rreq) 
		subreq->len	= size;



		atomic_inc(&rreq->nr_outstanding);

		spin_lock_bh(&rreq->lock);

		spin_lock(&rreq->lock);

		list_add_tail(&subreq->rreq_link, &rreq->subrequests);

		subreq->prev_donated = rreq->prev_donated;

		rreq->prev_donated = 0;

		trace_netfs_sreq(subreq, netfs_sreq_trace_added);

		spin_unlock_bh(&rreq->lock);

		spin_unlock(&rreq->lock);



		netfs_stat(&netfs_n_rh_download);

		if (rreq->netfs_ops->prepare_read) {

fs/netfs/read_collect.c

+10 −10
Original line number Diff line number Diff line
@@ -144,7 +144,7 @@ static bool netfs_consume_read_data(struct netfs_io_subrequest *subreq) 
	prev_donated = READ_ONCE(subreq->prev_donated);

	next_donated =  READ_ONCE(subreq->next_donated);

	if (prev_donated || next_donated) {

		spin_lock_bh(&rreq->lock);

		spin_lock(&rreq->lock);

		prev_donated = subreq->prev_donated;

		next_donated =  subreq->next_donated;

		subreq->start -= prev_donated;
@@ -157,7 +157,7 @@ static bool netfs_consume_read_data(struct netfs_io_subrequest *subreq) 
			next_donated = subreq->next_donated = 0;

		}

		trace_netfs_sreq(subreq, netfs_sreq_trace_add_donations);

		spin_unlock_bh(&rreq->lock);

		spin_unlock(&rreq->lock);

	}



	avail = subreq->transferred;
@@ -186,18 +186,18 @@ static bool netfs_consume_read_data(struct netfs_io_subrequest *subreq) 
		} else if (fpos < start) {

			excess = fend - subreq->start;



			spin_lock_bh(&rreq->lock);

			spin_lock(&rreq->lock);

			/* If we complete first on a folio split with the

			 * preceding subreq, donate to that subreq - otherwise

			 * we get the responsibility.

			 */

			if (subreq->prev_donated != prev_donated) {

				spin_unlock_bh(&rreq->lock);

				spin_unlock(&rreq->lock);

				goto donation_changed;

			}



			if (list_is_first(&subreq->rreq_link, &rreq->subrequests)) {

				spin_unlock_bh(&rreq->lock);

				spin_unlock(&rreq->lock);

				pr_err("Can't donate prior to front\n");

				goto bad;

			}
@@ -213,7 +213,7 @@ static bool netfs_consume_read_data(struct netfs_io_subrequest *subreq) 


			if (subreq->consumed >= subreq->len)

				goto remove_subreq_locked;

			spin_unlock_bh(&rreq->lock);

			spin_unlock(&rreq->lock);

		} else {

			pr_err("fpos > start\n");

			goto bad;
@@ -241,11 +241,11 @@ static bool netfs_consume_read_data(struct netfs_io_subrequest *subreq) 
	/* Donate the remaining downloaded data to one of the neighbouring

	 * subrequests.  Note that we may race with them doing the same thing.

	 */

	spin_lock_bh(&rreq->lock);

	spin_lock(&rreq->lock);



	if (subreq->prev_donated != prev_donated ||

	    subreq->next_donated != next_donated) {

		spin_unlock_bh(&rreq->lock);

		spin_unlock(&rreq->lock);

		cond_resched();

		goto donation_changed;

	}
@@ -296,11 +296,11 @@ static bool netfs_consume_read_data(struct netfs_io_subrequest *subreq) 
	goto remove_subreq_locked;



remove_subreq:

	spin_lock_bh(&rreq->lock);

	spin_lock(&rreq->lock);

remove_subreq_locked:

	subreq->consumed = subreq->len;

	list_del(&subreq->rreq_link);

	spin_unlock_bh(&rreq->lock);

	spin_unlock(&rreq->lock);

	netfs_put_subrequest(subreq, false, netfs_sreq_trace_put_consumed);

	return true;

fs/netfs/read_retry.c

+4 −4
Original line number Diff line number Diff line
@@ -142,12 +142,12 @@ static void netfs_retry_read_subrequests(struct netfs_io_request *rreq) 
			__clear_bit(NETFS_SREQ_MADE_PROGRESS, &subreq->flags);

			subreq->retry_count++;



			spin_lock_bh(&rreq->lock);

			spin_lock(&rreq->lock);

			list_add_tail(&subreq->rreq_link, &rreq->subrequests);

			subreq->prev_donated += rreq->prev_donated;

			rreq->prev_donated = 0;

			trace_netfs_sreq(subreq, netfs_sreq_trace_retry);

			spin_unlock_bh(&rreq->lock);

			spin_unlock(&rreq->lock);



			BUG_ON(!len);
@@ -217,9 +217,9 @@ static void netfs_retry_read_subrequests(struct netfs_io_request *rreq) 
		__clear_bit(NETFS_SREQ_FAILED, &subreq->flags);

		__clear_bit(NETFS_SREQ_NEED_RETRY, &subreq->flags);

	}

	spin_lock_bh(&rreq->lock);

	spin_lock(&rreq->lock);

	list_splice_tail_init(&queue, &rreq->subrequests);

	spin_unlock_bh(&rreq->lock);

	spin_unlock(&rreq->lock);

}



/*

fs/netfs/write_collect.c

+2 −2
Original line number Diff line number Diff line
@@ -238,14 +238,14 @@ static void netfs_collect_write_results(struct netfs_io_request *wreq) 


		cancel:

			/* Remove if completely consumed. */

			spin_lock_bh(&wreq->lock);

			spin_lock(&wreq->lock);



			remove = front;

			list_del_init(&front->rreq_link);

			front = list_first_entry_or_null(&stream->subrequests,

							 struct netfs_io_subrequest, rreq_link);

			stream->front = front;

			spin_unlock_bh(&wreq->lock);

			spin_unlock(&wreq->lock);

			netfs_put_subrequest(remove, false,

					     notes & SAW_FAILURE ?

					     netfs_sreq_trace_put_cancel :