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-rw-r--r--lib/iov_iter.c37
1 files changed, 33 insertions, 4 deletions
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 09fb73ad9d54..8be175df3075 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -596,6 +596,37 @@ static unsigned long memcpy_mcsafe_to_page(struct page *page, size_t offset,
return ret;
}
+static size_t copy_pipe_to_iter_mcsafe(const void *addr, size_t bytes,
+ struct iov_iter *i)
+{
+ struct pipe_inode_info *pipe = i->pipe;
+ size_t n, off, xfer = 0;
+ int idx;
+
+ if (!sanity(i))
+ return 0;
+
+ bytes = n = push_pipe(i, bytes, &idx, &off);
+ if (unlikely(!n))
+ return 0;
+ for ( ; n; idx = next_idx(idx, pipe), off = 0) {
+ size_t chunk = min_t(size_t, n, PAGE_SIZE - off);
+ unsigned long rem;
+
+ rem = memcpy_mcsafe_to_page(pipe->bufs[idx].page, off, addr,
+ chunk);
+ i->idx = idx;
+ i->iov_offset = off + chunk - rem;
+ xfer += chunk - rem;
+ if (rem)
+ break;
+ n -= chunk;
+ addr += chunk;
+ }
+ i->count -= xfer;
+ return xfer;
+}
+
/**
* _copy_to_iter_mcsafe - copy to user with source-read error exception handling
* @addr: source kernel address
@@ -627,10 +658,8 @@ size_t _copy_to_iter_mcsafe(const void *addr, size_t bytes, struct iov_iter *i)
const char *from = addr;
unsigned long rem, curr_addr, s_addr = (unsigned long) addr;
- if (unlikely(i->type & ITER_PIPE)) {
- WARN_ON(1);
- return 0;
- }
+ if (unlikely(i->type & ITER_PIPE))
+ return copy_pipe_to_iter_mcsafe(addr, bytes, i);
if (iter_is_iovec(i))
might_fault();
iterate_and_advance(i, bytes, v,