Merge tag 'v4.20-rc5' into for-4.21/block

Pull in v4.20-rc5, solving a conflict we'll otherwise get in aio.c and
also getting the merge fix that went into mainline that users are
hitting testing for-4.21/block and/or for-next.

* tag 'v4.20-rc5': (664 commits)
  Linux 4.20-rc5
  PCI: Fix incorrect value returned from pcie_get_speed_cap()
  MAINTAINERS: Update linux-mips mailing list address
  ocfs2: fix potential use after free
  mm/khugepaged: fix the xas_create_range() error path
  mm/khugepaged: collapse_shmem() do not crash on Compound
  mm/khugepaged: collapse_shmem() without freezing new_page
  mm/khugepaged: minor reorderings in collapse_shmem()
  mm/khugepaged: collapse_shmem() remember to clear holes
  mm/khugepaged: fix crashes due to misaccounted holes
  mm/khugepaged: collapse_shmem() stop if punched or truncated
  mm/huge_memory: fix lockdep complaint on 32-bit i_size_read()
  mm/huge_memory: splitting set mapping+index before unfreeze
  mm/huge_memory: rename freeze_page() to unmap_page()
  initramfs: clean old path before creating a hardlink
  kernel/kcov.c: mark funcs in __sanitizer_cov_trace_pc() as notrace
  psi: make disabling/enabling easier for vendor kernels
  proc: fixup map_files test on arm
  debugobjects: avoid recursive calls with kmemleak
  userfaultfd: shmem: UFFDIO_COPY: set the page dirty if VM_WRITE is not set
  ...

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;
 	}