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authorAl Viro <viro@zeniv.linux.org.uk>2018-11-25 16:24:16 -0500
committerAl Viro <viro@zeniv.linux.org.uk>2018-11-25 16:24:49 -0500
commit78e1f386170798159a81fdbc5e131836fd808048 (patch)
tree4f7a6e6f8b18f87216d7d1ef91099646821d199e
parent2084ac6c505a58f7efdec13eba633c6aaa085ca5 (diff)
iov_iter: teach csum_and_copy_to_iter() to handle pipe-backed ones
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
-rw-r--r--lib/iov_iter.c38
1 files changed, 37 insertions, 1 deletions
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 7ebccb5c1637..54c248526b55 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -560,6 +560,38 @@ static size_t copy_pipe_to_iter(const void *addr, size_t bytes,
return bytes;
}
+static size_t csum_and_copy_to_pipe_iter(const void *addr, size_t bytes,
+ __wsum *csum, struct iov_iter *i)
+{
+ struct pipe_inode_info *pipe = i->pipe;
+ size_t n, r;
+ size_t off = 0;
+ __wsum sum = *csum, next;
+ int idx;
+
+ if (!sanity(i))
+ return 0;
+
+ bytes = n = push_pipe(i, bytes, &idx, &r);
+ if (unlikely(!n))
+ return 0;
+ for ( ; n; idx = next_idx(idx, pipe), r = 0) {
+ size_t chunk = min_t(size_t, n, PAGE_SIZE - r);
+ char *p = kmap_atomic(pipe->bufs[idx].page);
+ next = csum_partial_copy_nocheck(addr, p + r, chunk, 0);
+ sum = csum_block_add(sum, next, off);
+ kunmap_atomic(p);
+ i->idx = idx;
+ i->iov_offset = r + chunk;
+ n -= chunk;
+ off += chunk;
+ addr += chunk;
+ }
+ i->count -= bytes;
+ *csum = sum;
+ return bytes;
+}
+
size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i)
{
const char *from = addr;
@@ -1438,8 +1470,12 @@ size_t csum_and_copy_to_iter(const void *addr, size_t bytes, __wsum *csum,
const char *from = addr;
__wsum sum, next;
size_t off = 0;
+
+ if (unlikely(iov_iter_is_pipe(i)))
+ return csum_and_copy_to_pipe_iter(addr, bytes, csum, i);
+
sum = *csum;
- if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) {
+ if (unlikely(iov_iter_is_discard(i))) {
WARN_ON(1); /* for now */
return 0;
}