提交 0f1d344f 编写于 作者: P Pavel Begunkov 提交者: Jens Axboe

splice: don't generate zero-len segement bvecs

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: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NPavel Begunkov <asml.silence@gmail.com>
Reviewed-by: NMing Lei <ming.lei@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
上级 684da762
......@@ -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);
......
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