From: NeilBrown Date: Fri, 4 May 2012 07:03:18 +0000 (+1000) Subject: md/bitmap: fix calculation of 'chunks' - missing shift. X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=b16b1b6cd052acbacc0a15f934bca9b354534d48;p=sagit-ice-cold%2Fkernel_xiaomi_msm8998.git md/bitmap: fix calculation of 'chunks' - missing shift. commit 61a0d80c "md/bitmap: discard CHUNK_BLOCK_SHIFT macro" replaced CHUNK_BLOCK_RATIO() by the same text that was replacing CHUNK_BLOCK_SHIFT() - which is clearly wrong. The result is that 'chunks' is often too small by 1, which can sometimes result in a crash (not sure how). So use the correct replacement, and get rid of CHUNK_BLOCK_RATIO which is no longe used. Reported-by: Karl Newman Tested-by: Karl Newman Signed-off-by: NeilBrown --- diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c index 97e73e555d11..17e2b472e16d 100644 --- a/drivers/md/bitmap.c +++ b/drivers/md/bitmap.c @@ -1727,8 +1727,7 @@ int bitmap_create(struct mddev *mddev) bitmap->chunkshift = (ffz(~mddev->bitmap_info.chunksize) - BITMAP_BLOCK_SHIFT); - /* now that chunksize and chunkshift are set, we can use these macros */ - chunks = (blocks + bitmap->chunkshift - 1) >> + chunks = (blocks + (1 << bitmap->chunkshift) - 1) >> bitmap->chunkshift; pages = (chunks + PAGE_COUNTER_RATIO - 1) / PAGE_COUNTER_RATIO; diff --git a/drivers/md/bitmap.h b/drivers/md/bitmap.h index 55ca5aec84e4..b44b0aba2d47 100644 --- a/drivers/md/bitmap.h +++ b/drivers/md/bitmap.h @@ -101,9 +101,6 @@ typedef __u16 bitmap_counter_t; #define BITMAP_BLOCK_SHIFT 9 -/* how many blocks per chunk? (this is variable) */ -#define CHUNK_BLOCK_RATIO(bitmap) ((bitmap)->mddev->bitmap_info.chunksize >> BITMAP_BLOCK_SHIFT) - #endif /*