Pull copy_to_iter_mc fix from Al Viro:
"Backportable fix for copy_to_iter_mc() - the second part of iov_iter
work will pretty much overwrite this, but would be much harder to
backport"
* tag 'pull-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
fix short copy handling in copy_mc_pipe_to_iter()
return buf->ops->try_steal(pipe, buf);
}
+static inline void pipe_discard_from(struct pipe_inode_info *pipe,
+ unsigned int old_head)
+{
+ unsigned int mask = pipe->ring_size - 1;
+
+ while (pipe->head > old_head)
+ pipe_buf_release(pipe, &pipe->bufs[--pipe->head & mask]);
+}
+
/* Differs from PIPE_BUF in that PIPE_SIZE is the length of the actual
memory allocation, whereas PIPE_BUF makes atomicity guarantees. */
#define PIPE_SIZE PAGE_SIZE
struct pipe_inode_info *pipe = i->pipe;
unsigned int p_mask = pipe->ring_size - 1;
unsigned int i_head;
+ unsigned int valid = pipe->head;
size_t n, off, xfer = 0;
if (!sanity(i))
rem = copy_mc_to_kernel(p + off, addr + xfer, chunk);
chunk -= rem;
kunmap_local(p);
- i->head = i_head;
- i->iov_offset = off + chunk;
- xfer += chunk;
- if (rem)
+ if (chunk) {
+ i->head = i_head;
+ i->iov_offset = off + chunk;
+ xfer += chunk;
+ valid = i_head + 1;
+ }
+ if (rem) {
+ pipe->bufs[i_head & p_mask].len -= rem;
+ pipe_discard_from(pipe, valid);
break;
+ }
n -= chunk;
off = 0;
i_head++;