Commit a5117181 authored by Martin Schwidefsky's avatar Martin Schwidefsky Committed by Linus Torvalds
Browse files

[PATCH] broken fault_in_pages_readable call in generic_file_buffered_write() 



fault_in_pages_readable() is being passed an incorrect `end' address, which
can result in writes accidentally faulting in pages which will not be affected
by the write() call.

Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 7cef5677

mm/filemap.c

+7 −1
Original line number Diff line number Diff line
@@ -1968,6 +1968,7 @@ generic_file_buffered_write(struct kiocb *iocb, const struct iovec *iov, 
	do {

		unsigned long index;

		unsigned long offset;

		unsigned long maxlen;

		size_t copied;



		offset = (pos & (PAGE_CACHE_SIZE -1)); /* Within page */
@@ -1982,7 +1983,10 @@ generic_file_buffered_write(struct kiocb *iocb, const struct iovec *iov, 
		 * same page as we're writing to, without it being marked

		 * up-to-date.

		 */

		fault_in_pages_readable(buf, bytes);

		maxlen = cur_iov->iov_len - iov_base;

		if (maxlen > bytes)

			maxlen = bytes;

		fault_in_pages_readable(buf, maxlen);



		page = __grab_cache_page(mapping,index,&cached_page,&lru_pvec);

		if (!page) {
@@ -2024,6 +2028,8 @@ generic_file_buffered_write(struct kiocb *iocb, const struct iovec *iov, 
					filemap_set_next_iovec(&cur_iov,

							&iov_base, status);

					buf = cur_iov->iov_base + iov_base;

				} else {

					iov_base += status;

				}

			}

		}