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ITER_PIPE: clean pipe_advance() up

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instead of setting ->iov_offset for new position and calling
pipe_truncate() to adjust ->len of the last buffer and discard
everything after it, adjust ->len at the same time we set ->iov_offset
and use pipe_discard_from() to deal with buffers past that.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2022-06-15 16:03:25 -04:00
parent ca59196754
commit 2c855de933
1 changed files with 18 additions and 18 deletions
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36
lib/iov_iter.c
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@ -845,27 +845,27 @@ static inline void pipe_truncate(struct iov_iter *i)
static void pipe_advance(struct iov_iter *i, size_t size)
{
struct pipe_inode_info *pipe = i->pipe;
if (size) {
struct pipe_buffer *buf;
unsigned int p_mask = pipe->ring_size - 1;
unsigned int i_head = i->head;
size_t off = i->iov_offset, left = size;
unsigned int off = i->iov_offset;
if (off) /* make it relative to the beginning of buffer */
left += off - pipe->bufs[i_head & p_mask].offset;
while (1) {
buf = &pipe->bufs[i_head & p_mask];
if (left <= buf->len)
break;
left -= buf->len;
i_head++;
}
i->head = i_head;
i->iov_offset = buf->offset + left;
if (!off && !size) {
pipe_discard_from(pipe, i->start_head); // discard everything
return;
}
i->count -= size;
/* ... and discard everything past that point */
pipe_truncate(i);
while (1) {
struct pipe_buffer *buf = pipe_buf(pipe, i->head);
if (off) /* make it relative to the beginning of buffer */
size += off - buf->offset;
if (size <= buf->len) {
buf->len = size;
i->iov_offset = buf->offset + size;
break;
}
size -= buf->len;
i->head++;
off = 0;
}
pipe_discard_from(pipe, i->head + 1); // discard everything past this one
}
static void iov_iter_bvec_advance(struct iov_iter *i, size_t size)