Commit b6bc8a7b authored Dec 16, 2018 by Long Li Committed by Steve French Dec 23, 2018

CIFS: use the correct length when pinning memory for direct I/O for write



The current code attempts to pin memory using the largest possible wsize
based on the currect SMB credits. This doesn't cause kernel oops but this
is not optimal as we may pin more pages then actually needed.

Fix this by only pinning what are needed for doing this write I/O.

Signed-off-by: Long Li <longli@microsoft.com>
Cc: stable@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Joey Pabalinas <joeypabalinas@gmail.com>

parent 59a63e47

fs/cifs/file.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -2617,11 +2617,13 @@ cifs_write_from_iter(loff_t offset, size_t len, struct iov_iter *from,
		if (rc)
		break;

		cur_len = min_t(const size_t, len, wsize);

		if (ctx->direct_io) {
		ssize_t result;

		result = iov_iter_get_pages_alloc(
		from, &pagevec, wsize, &start);
		from, &pagevec, cur_len, &start);
		if (result < 0) {
		cifs_dbg(VFS,
		"direct_writev couldn't get user pages "

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