From 4fcccc38ebbdcff74494701c50a8e2fe4689837e Mon Sep 17 00:00:00 2001 From: David Howells Date: Wed, 4 Oct 2023 16:15:48 +0100 Subject: netfs: Make the refcounting of netfs_begin_read() easier to use Make the refcounting of netfs_begin_read() easier to use by not eating the caller's ref on the netfs_io_request it's given. This makes it easier to use when we need to look in the request struct after. Signed-off-by: David Howells Reviewed-by: Jeff Layton cc: linux-cachefs@redhat.com cc: linux-fsdevel@vger.kernel.org cc: linux-mm@kvack.org --- fs/netfs/buffered_read.c | 6 +++++- fs/netfs/io.c | 28 +++++++++++++--------------- 2 files changed, 18 insertions(+), 16 deletions(-) (limited to 'fs/netfs') diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c index 751556faa70b..6b9a44cafbac 100644 --- a/fs/netfs/buffered_read.c +++ b/fs/netfs/buffered_read.c @@ -210,6 +210,7 @@ void netfs_readahead(struct readahead_control *ractl) ; netfs_begin_read(rreq, false); + netfs_put_request(rreq, false, netfs_rreq_trace_put_return); return; cleanup_free: @@ -260,7 +261,9 @@ int netfs_read_folio(struct file *file, struct folio *folio) iov_iter_xarray(&rreq->iter, ITER_DEST, &mapping->i_pages, rreq->start, rreq->len); - return netfs_begin_read(rreq, true); + ret = netfs_begin_read(rreq, true); + netfs_put_request(rreq, false, netfs_rreq_trace_put_return); + return ret; discard: netfs_put_request(rreq, false, netfs_rreq_trace_put_discard); @@ -429,6 +432,7 @@ retry: ret = netfs_begin_read(rreq, true); if (ret < 0) goto error; + netfs_put_request(rreq, false, netfs_rreq_trace_put_return); have_folio: ret = folio_wait_fscache_killable(folio); diff --git a/fs/netfs/io.c b/fs/netfs/io.c index e228bfb530ea..e83ef5835d25 100644 --- a/fs/netfs/io.c +++ b/fs/netfs/io.c @@ -362,6 +362,7 @@ again: netfs_rreq_unlock_folios(rreq); + 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); @@ -657,7 +658,6 @@ int netfs_begin_read(struct netfs_io_request *rreq, bool sync) if (rreq->len == 0) { pr_err("Zero-sized read [R=%x]\n", rreq->debug_id); - netfs_put_request(rreq, false, netfs_rreq_trace_put_zero_len); return -EIO; } @@ -665,12 +665,10 @@ int netfs_begin_read(struct netfs_io_request *rreq, bool sync) INIT_WORK(&rreq->work, netfs_rreq_work); - if (sync) - netfs_get_request(rreq, netfs_rreq_trace_get_hold); - /* Chop the read into slices according to what the cache and the netfs * want and submit each one. */ + netfs_get_request(rreq, netfs_rreq_trace_get_for_outstanding); atomic_set(&rreq->nr_outstanding, 1); io_iter = rreq->io_iter; do { @@ -680,25 +678,25 @@ int netfs_begin_read(struct netfs_io_request *rreq, bool sync) } while (rreq->submitted < rreq->len); if (sync) { - /* Keep nr_outstanding incremented so that the ref always belongs to - * us, and the service code isn't punted off to a random thread pool to - * process. + /* Keep nr_outstanding incremented so that the ref always + * belongs to us, and the service code isn't punted off to a + * random thread pool to process. Note that this might start + * further work, such as writing to the cache. */ - for (;;) { - wait_var_event(&rreq->nr_outstanding, - atomic_read(&rreq->nr_outstanding) == 1); + wait_var_event(&rreq->nr_outstanding, + atomic_read(&rreq->nr_outstanding) == 1); + if (atomic_dec_and_test(&rreq->nr_outstanding)) netfs_rreq_assess(rreq, false); - if (!test_bit(NETFS_RREQ_IN_PROGRESS, &rreq->flags)) - break; - cond_resched(); - } + + trace_netfs_rreq(rreq, netfs_rreq_trace_wait_ip); + wait_on_bit(&rreq->flags, NETFS_RREQ_IN_PROGRESS, + TASK_UNINTERRUPTIBLE); ret = rreq->error; if (ret == 0 && rreq->submitted < rreq->len) { trace_netfs_failure(rreq, NULL, ret, netfs_fail_short_read); ret = -EIO; } - netfs_put_request(rreq, false, netfs_rreq_trace_put_hold); } else { /* If we decrement nr_outstanding to 0, the ref belongs to us. */ if (atomic_dec_and_test(&rreq->nr_outstanding)) -- cgit v1.2.3