Merge branch 'for-davem' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
diff --git a/include/linux/uio.h b/include/linux/uio.h
index 804e34c..f2d36a3 100644
--- a/include/linux/uio.h
+++ b/include/linux/uio.h
@@ -39,7 +39,10 @@ struct iov_iter {
};
union {
unsigned long nr_segs;
- int idx;
+ struct {
+ int idx;
+ int start_idx;
+ };
};
};
@@ -81,6 +84,7 @@ unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to);
size_t iov_iter_copy_from_user_atomic(struct page *page,
struct iov_iter *i, unsigned long offset, size_t bytes);
void iov_iter_advance(struct iov_iter *i, size_t bytes);
+void iov_iter_revert(struct iov_iter *i, size_t bytes);
int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes);
size_t iov_iter_single_seg_count(const struct iov_iter *i);
size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index e68604a..60abc44 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -786,6 +786,68 @@ void iov_iter_advance(struct iov_iter *i, size_t size)
}
EXPORT_SYMBOL(iov_iter_advance);
+void iov_iter_revert(struct iov_iter *i, size_t unroll)
+{
+ if (!unroll)
+ return;
+ i->count += unroll;
+ if (unlikely(i->type & ITER_PIPE)) {
+ struct pipe_inode_info *pipe = i->pipe;
+ int idx = i->idx;
+ size_t off = i->iov_offset;
+ while (1) {
+ size_t n = off - pipe->bufs[idx].offset;
+ if (unroll < n) {
+ off -= (n - unroll);
+ break;
+ }
+ unroll -= n;
+ if (!unroll && idx == i->start_idx) {
+ off = 0;
+ break;
+ }
+ if (!idx--)
+ idx = pipe->buffers - 1;
+ off = pipe->bufs[idx].offset + pipe->bufs[idx].len;
+ }
+ i->iov_offset = off;
+ i->idx = idx;
+ pipe_truncate(i);
+ return;
+ }
+ if (unroll <= i->iov_offset) {
+ i->iov_offset -= unroll;
+ return;
+ }
+ unroll -= i->iov_offset;
+ if (i->type & ITER_BVEC) {
+ const struct bio_vec *bvec = i->bvec;
+ while (1) {
+ size_t n = (--bvec)->bv_len;
+ i->nr_segs++;
+ if (unroll <= n) {
+ i->bvec = bvec;
+ i->iov_offset = n - unroll;
+ return;
+ }
+ unroll -= n;
+ }
+ } else { /* same logics for iovec and kvec */
+ const struct iovec *iov = i->iov;
+ while (1) {
+ size_t n = (--iov)->iov_len;
+ i->nr_segs++;
+ if (unroll <= n) {
+ i->iov = iov;
+ i->iov_offset = n - unroll;
+ return;
+ }
+ unroll -= n;
+ }
+ }
+}
+EXPORT_SYMBOL(iov_iter_revert);
+
/*
* Return the count of just the current iov_iter segment.
*/
@@ -839,6 +901,7 @@ void iov_iter_pipe(struct iov_iter *i, int direction,
i->idx = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1);
i->iov_offset = 0;
i->count = count;
+ i->start_idx = i->idx;
}
EXPORT_SYMBOL(iov_iter_pipe);
diff --git a/net/core/datagram.c b/net/core/datagram.c
index ea63334..f4947e7 100644
--- a/net/core/datagram.c
+++ b/net/core/datagram.c
@@ -398,7 +398,7 @@ int skb_copy_datagram_iter(const struct sk_buff *skb, int offset,
struct iov_iter *to, int len)
{
int start = skb_headlen(skb);
- int i, copy = start - offset;
+ int i, copy = start - offset, start_off = offset, n;
struct sk_buff *frag_iter;
trace_skb_copy_datagram_iovec(skb, len);
@@ -407,11 +407,12 @@ int skb_copy_datagram_iter(const struct sk_buff *skb, int offset,
if (copy > 0) {
if (copy > len)
copy = len;
- if (copy_to_iter(skb->data + offset, copy, to) != copy)
+ n = copy_to_iter(skb->data + offset, copy, to);
+ offset += n;
+ if (n != copy)
goto short_copy;
if ((len -= copy) == 0)
return 0;
- offset += copy;
}
/* Copy paged appendix. Hmm... why does this look so complicated? */
@@ -425,13 +426,14 @@ int skb_copy_datagram_iter(const struct sk_buff *skb, int offset,
if ((copy = end - offset) > 0) {
if (copy > len)
copy = len;
- if (copy_page_to_iter(skb_frag_page(frag),
+ n = copy_page_to_iter(skb_frag_page(frag),
frag->page_offset + offset -
- start, copy, to) != copy)
+ start, copy, to);
+ offset += n;
+ if (n != copy)
goto short_copy;
if (!(len -= copy))
return 0;
- offset += copy;
}
start = end;
}
@@ -463,6 +465,7 @@ int skb_copy_datagram_iter(const struct sk_buff *skb, int offset,
*/
fault:
+ iov_iter_revert(to, offset - start_off);
return -EFAULT;
short_copy:
@@ -613,7 +616,7 @@ static int skb_copy_and_csum_datagram(const struct sk_buff *skb, int offset,
__wsum *csump)
{
int start = skb_headlen(skb);
- int i, copy = start - offset;
+ int i, copy = start - offset, start_off = offset;
struct sk_buff *frag_iter;
int pos = 0;
int n;
@@ -623,11 +626,11 @@ static int skb_copy_and_csum_datagram(const struct sk_buff *skb, int offset,
if (copy > len)
copy = len;
n = csum_and_copy_to_iter(skb->data + offset, copy, csump, to);
+ offset += n;
if (n != copy)
goto fault;
if ((len -= copy) == 0)
return 0;
- offset += copy;
pos = copy;
}
@@ -649,12 +652,12 @@ static int skb_copy_and_csum_datagram(const struct sk_buff *skb, int offset,
offset - start, copy,
&csum2, to);
kunmap(page);
+ offset += n;
if (n != copy)
goto fault;
*csump = csum_block_add(*csump, csum2, pos);
if (!(len -= copy))
return 0;
- offset += copy;
pos += copy;
}
start = end;
@@ -687,6 +690,7 @@ static int skb_copy_and_csum_datagram(const struct sk_buff *skb, int offset,
return 0;
fault:
+ iov_iter_revert(to, offset - start_off);
return -EFAULT;
}
@@ -771,6 +775,7 @@ int skb_copy_and_csum_datagram_msg(struct sk_buff *skb,
}
return 0;
csum_error:
+ iov_iter_revert(&msg->msg_iter, chunk);
return -EINVAL;
fault:
return -EFAULT;