From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=43246 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1P66ei-0004wl-4h for qemu-devel@nongnu.org; Wed, 13 Oct 2010 15:06:29 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1P66eg-0000Fa-4j for qemu-devel@nongnu.org; Wed, 13 Oct 2010 15:06:27 -0400 Received: from moutng.kundenserver.de ([212.227.126.187]:62632) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1P66ef-0000FI-PF for qemu-devel@nongnu.org; Wed, 13 Oct 2010 15:06:26 -0400 Message-ID: <4CB6032E.9050802@mail.berlios.de> Date: Wed, 13 Oct 2010 21:06:22 +0200 From: Stefan Weil MIME-Version: 1.0 References: <1285267031-22966-1-git-send-email-weil@mail.berlios.de> <4C9BA48A.1090600@mail.berlios.de> <4C9BA64F.7030303@mail.berlios.de> <4C9BC53E.1010509@mail.berlios.de> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Subject: [Qemu-devel] Re: [PATCH] block: Use GCC_FMT_ATTR and fix a format error List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Kevin Wolf Cc: Blue Swirl , QEMU Developers Am 25.09.2010 10:01, schrieb Blue Swirl: > On Thu, Sep 23, 2010 at 9:23 PM, Stefan Weil wrote: > >> Am 23.09.2010 22:24, schrieb Blue Swirl: >> >>> On Thu, Sep 23, 2010 at 7:11 PM, Stefan Weil wrote: >>> >>>> Am 23.09.2010 21:03, schrieb Stefan Weil: >>>> >>>>> Am 23.09.2010 20:53, schrieb Blue Swirl: >>>>> >>>>>> On Thu, Sep 23, 2010 at 6:37 PM, Stefan Weil >>>>>> wrote: >>>>>> >>>>>>> Adding the gcc format attribute detects a format bug >>>>>>> which is fixed here. >>>>>>> >>>>>>> Cc: Blue Swirl >>>>>>> Cc: Kevin Wolf >>>>>>> Signed-off-by: Stefan Weil >>>>>>> --- >>>>>>> block/blkverify.c | 5 +++-- >>>>>>> 1 files changed, 3 insertions(+), 2 deletions(-) >>>>>>> >>>>>>> diff --git a/block/blkverify.c b/block/blkverify.c >>>>>>> index 8083464..b39fb67 100644 >>>>>>> --- a/block/blkverify.c >>>>>>> +++ b/block/blkverify.c >>>>>>> @@ -53,7 +53,8 @@ static AIOPool blkverify_aio_pool = { >>>>>>> .cancel = blkverify_aio_cancel, >>>>>>> }; >>>>>>> >>>>>>> -static void blkverify_err(BlkverifyAIOCB *acb, const char *fmt, ...) >>>>>>> +static void GCC_FMT_ATTR(2, 3) blkverify_err(BlkverifyAIOCB *acb, >>>>>>> + const char *fmt, ...) >>>>>>> { >>>>>>> va_list ap; >>>>>>> >>>>>>> @@ -300,7 +301,7 @@ static void blkverify_verify_readv(BlkverifyAIOCB >>>>>>> *acb) >>>>>>> ssize_t offset = blkverify_iovec_compare(acb->qiov,&acb->raw_qiov); >>>>>>> if (offset != -1) { >>>>>>> blkverify_err(acb, "contents mismatch in sector %ld", >>>>>>> - acb->sector_num + (offset / BDRV_SECTOR_SIZE)); >>>>>>> + (long)(acb->sector_num + (offset / >>>>>>> BDRV_SECTOR_SIZE))); >>>>>>> >>>>>> sector_num is int64_t, so the correct fix is to change '%ld' to '%" >>>>>> PRId64'. >>>>>> >>>>>> >>>>> I noticed that, too. But offset is ssize_t. >>>>> Can you always be sure that (int64_t + ssize_t) results in a int64_t? >>>>> I don't think it's so easy. >>>>> >>>> I think you are correct, the format should use PRId64. >>>> The type cast is still necessary, but should cast to int64_t. >>>> (needed when int64_t == long and ssize_t == long long). >>>> >>>> If you agree, I'll send a new patch. >>>> >>> It's also possible to cast offset to int64_t. Or perhaps even the type >>> of the return value of blkverify_iovec_compare should be changed to >>> int64_t. >>> >> Unless BDRV_SECTOR_SIZE is changed, too, this would >> still need a type cast. So we have two possible solutions: >> >> (1) Use %lld (should work because BDRV_SECTOR_SIZE is unsigned long long). >> (2) Use PRId64. This needs changes for BDRV_SECTOR_SIZE and >> blkverify_iovec_compare. >> > Or > (3) Use PRId64, change blkverify_iovec_compare, leave BDRV_SECTOR_SIZE > unchanged but add a cast to int64_t here. > > Grepping for BDRV_SECTOR_SIZE shows that it is used in several places > in size_t or off_t expressions, so long long is as good as any other > large type. > > I think Kevin should decide. > Kevin, how should this get fixed? I suggest committing my last patch version sent on 2010-09-24 ("[PATCH] block: Use GCC_FMT_ATTR and fix a format error"), but I don't mind if you have a different solution. Regards, Stefan