| Message ID | ca14f80bf5156d83b38f543be2b9434a571474c9.1609461359.git.asml.silence@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | no-copy bvec | expand |
On Sat, Jan 02, 2021 at 03:17:33PM +0000, Pavel Begunkov wrote: > iter_file_splice_write() may spawn bvec segments with zero-length. In > preparation for prohibiting them, filter out by hand at splice level. > > Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> > --- > fs/splice.c | 9 +++++---- > 1 file changed, 5 insertions(+), 4 deletions(-) > > diff --git a/fs/splice.c b/fs/splice.c > index 866d5c2367b2..7299330c3270 100644 > --- a/fs/splice.c > +++ b/fs/splice.c > @@ -644,7 +644,6 @@ iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out, > ret = splice_from_pipe_next(pipe, &sd); > if (ret <= 0) > break; > - Spurious empty line removal.. > + if (!this_len) > + continue; Maybe throw in a comment on why we skip empty segments here? Otherwise looks good: Reviewed-by: Christoph Hellwig <hch@lst.de>
On 04/01/2021 16:17, Christoph Hellwig wrote: > On Sat, Jan 02, 2021 at 03:17:33PM +0000, Pavel Begunkov wrote: >> iter_file_splice_write() may spawn bvec segments with zero-length. In >> preparation for prohibiting them, filter out by hand at splice level. >> >> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> >> --- >> fs/splice.c | 9 +++++---- >> 1 file changed, 5 insertions(+), 4 deletions(-) >> >> diff --git a/fs/splice.c b/fs/splice.c >> index 866d5c2367b2..7299330c3270 100644 >> --- a/fs/splice.c >> +++ b/fs/splice.c >> @@ -644,7 +644,6 @@ iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out, >> ret = splice_from_pipe_next(pipe, &sd); >> if (ret <= 0) >> break; >> - > > Spurious empty line removal.. > >> + if (!this_len) >> + continue; > > Maybe throw in a comment on why we skip empty segments here? Definitely won't hurt. Thanks for taking a look > > Otherwise looks good: > > Reviewed-by: Christoph Hellwig <hch@lst.de> > -- Pavel Begunkov
diff --git a/fs/splice.c b/fs/splice.c index 866d5c2367b2..7299330c3270 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -644,7 +644,6 @@ iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out, ret = splice_from_pipe_next(pipe, &sd); if (ret <= 0) break; - if (unlikely(nbufs < pipe->max_usage)) { kfree(array); nbufs = pipe->max_usage; @@ -662,12 +661,13 @@ 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; + if (!this_len) + continue; + this_len = min(this_len, left); ret = pipe_buf_confirm(pipe, buf); if (unlikely(ret)) { @@ -680,6 +680,7 @@ 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);
iter_file_splice_write() may spawn bvec segments with zero-length. In preparation for prohibiting them, filter out by hand at splice level. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> --- fs/splice.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)