4.20-stable review patch. If anyone has any objections, please let me know.
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From: Long Li longli@microsoft.com
commit b6bc8a7b993e62f82415a5e3e4a6469e80fea19c upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/cifs/file.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/fs/cifs/file.c +++ b/fs/cifs/file.c @@ -2617,11 +2617,13 @@ cifs_write_from_iter(loff_t offset, size 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 "