From 6fcc5420bfb91049a318bb4d88fe471248b5b391 Mon Sep 17 00:00:00 2001 From: Boaz Harrosh Date: Sun, 20 Jul 2014 12:09:04 +0300 Subject: direct-io: fix uninitialized warning in do_direct_IO() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The following warnings: fs/direct-io.c: In function ‘__blockdev_direct_IO’: fs/direct-io.c:1011:12: warning: ‘to’ may be used uninitialized in this function [-Wmaybe-uninitialized] fs/direct-io.c:913:16: note: ‘to’ was declared here fs/direct-io.c:1011:12: warning: ‘from’ may be used uninitialized in this function [-Wmaybe-uninitialized] fs/direct-io.c:913:10: note: ‘from’ was declared here are false positive because dio_get_page() either fails, or sets both 'from' and 'to'. Paul Bolle said ... Maybe it's better to move initializing "to" and "from" out of dio_get_page(). That _might_ make it easier for both the the reader and the compiler to understand what's going on. Something like this: Christoph Hellwig said ... The fix of moving the code definitively looks nicer, while I think uninitialized_var is horrible wart that won't get anywhere near my code. Boaz Harrosh: I agree with Christoph and Paul Signed-off-by: Boaz Harrosh Signed-off-by: Christoph Hellwig --- fs/direct-io.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) (limited to 'fs/direct-io.c') diff --git a/fs/direct-io.c b/fs/direct-io.c index 98040ba388ac..194d0d122cae 100644 --- a/fs/direct-io.c +++ b/fs/direct-io.c @@ -198,9 +198,8 @@ static inline int dio_refill_pages(struct dio *dio, struct dio_submit *sdio) * L1 cache. */ static inline struct page *dio_get_page(struct dio *dio, - struct dio_submit *sdio, size_t *from, size_t *to) + struct dio_submit *sdio) { - int n; if (dio_pages_present(sdio) == 0) { int ret; @@ -209,10 +208,7 @@ static inline struct page *dio_get_page(struct dio *dio, return ERR_PTR(ret); BUG_ON(dio_pages_present(sdio) == 0); } - n = sdio->head++; - *from = n ? 0 : sdio->from; - *to = (n == sdio->tail - 1) ? sdio->to : PAGE_SIZE; - return dio->pages[n]; + return dio->pages[sdio->head]; } /** @@ -911,11 +907,15 @@ static int do_direct_IO(struct dio *dio, struct dio_submit *sdio, while (sdio->block_in_file < sdio->final_block_in_request) { struct page *page; size_t from, to; - page = dio_get_page(dio, sdio, &from, &to); + + page = dio_get_page(dio, sdio); if (IS_ERR(page)) { ret = PTR_ERR(page); goto out; } + from = sdio->head ? 0 : sdio->from; + to = (sdio->head == sdio->tail - 1) ? sdio->to : PAGE_SIZE; + sdio->head++; while (from < to) { unsigned this_chunk_bytes; /* # of bytes mapped */ -- cgit v1.2.3-59-g8ed1b