From: Pavel Begunkov <asml.silence@gmail.com>
To: linux-block@vger.kernel.org
Cc: Jens Axboe <axboe@kernel.dk>,
Christoph Hellwig <hch@infradead.org>,
Matthew Wilcox <willy@infradead.org>,
Ming Lei <ming.lei@redhat.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
"Darrick J . Wong" <darrick.wong@oracle.com>,
"Martin K . Petersen" <martin.petersen@oracle.com>,
Jonathan Corbet <corbet@lwn.net>,
linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
io-uring@vger.kernel.org, linux-kernel@vger.kernel.org,
target-devel@vger.kernel.org, linux-scsi@vger.kernel.org,
linux-doc@vger.kernel.org, Christoph Hellwig <hch@lst.de>
Subject: [PATCH v3 1/7] splice: don't generate zero-len segement bvecs
Date: Sat, 9 Jan 2021 16:02:57 +0000 [thread overview]
Message-ID: <bfaeb54c88f0c962461b75c6493103e11bb0b17b.1610170479.git.asml.silence@gmail.com> (raw)
In-Reply-To: <cover.1610170479.git.asml.silence@gmail.com>
iter_file_splice_write() may spawn bvec segments with zero-length. In
preparation for prohibiting them, filter out by hand at splice level.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
fs/splice.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/fs/splice.c b/fs/splice.c
index 866d5c2367b2..474fb8b5562a 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -662,12 +662,14 @@ iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
/* build the vector */
left = sd.total_len;
- for (n = 0; !pipe_empty(head, tail) && left && n < nbufs; tail++, n++) {
+ for (n = 0; !pipe_empty(head, tail) && left && n < nbufs; tail++) {
struct pipe_buffer *buf = &pipe->bufs[tail & mask];
size_t this_len = buf->len;
- if (this_len > left)
- this_len = left;
+ /* zero-length bvecs are not supported, skip them */
+ if (!this_len)
+ continue;
+ this_len = min(this_len, left);
ret = pipe_buf_confirm(pipe, buf);
if (unlikely(ret)) {
@@ -680,6 +682,7 @@ iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
array[n].bv_len = this_len;
array[n].bv_offset = buf->offset;
left -= this_len;
+ n++;
}
iov_iter_bvec(&from, WRITE, array, n, sd.total_len - left);
--
2.24.0
next prev parent reply other threads:[~2021-01-09 16:08 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-09 16:02 [PATCH v3 0/7] no-copy bvec Pavel Begunkov
2021-01-09 16:02 ` Pavel Begunkov [this message]
2021-01-11 2:48 ` [PATCH v3 1/7] splice: don't generate zero-len segement bvecs Ming Lei
2021-01-09 16:02 ` [PATCH v3 2/7] bvec/iter: disallow zero-length segment bvecs Pavel Begunkov
2021-01-11 2:49 ` Ming Lei
2021-01-09 16:02 ` [PATCH v3 3/7] block/psi: remove PSI annotations from direct IO Pavel Begunkov
2021-01-11 2:52 ` Ming Lei
2021-01-09 16:03 ` [PATCH v3 4/7] target/file: allocate the bvec array as part of struct target_core_file_cmd Pavel Begunkov
2021-01-11 2:53 ` Ming Lei
2021-01-09 16:03 ` [PATCH v3 5/7] iov_iter: optimise bvec iov_iter_advance() Pavel Begunkov
2021-01-11 2:55 ` Ming Lei
2021-01-09 16:03 ` [PATCH v3 6/7] bio: add a helper calculating nr segments to alloc Pavel Begunkov
2021-01-11 2:57 ` Ming Lei
2021-01-09 16:03 ` [PATCH v3 7/7] bio: don't copy bvec for direct IO Pavel Begunkov
2021-01-11 3:00 ` Ming Lei
2021-01-25 15:58 ` [PATCH v3 0/7] no-copy bvec Jens Axboe
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