From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=36703 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1OytG9-0005GU-Ok for qemu-devel@nongnu.org; Thu, 23 Sep 2010 17:23:18 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1OytG7-0001bU-Ag for qemu-devel@nongnu.org; Thu, 23 Sep 2010 17:23:17 -0400 Received: from moutng.kundenserver.de ([212.227.17.10]:60671) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1OytG6-0001bD-Sv for qemu-devel@nongnu.org; Thu, 23 Sep 2010 17:23:15 -0400 Message-ID: <4C9BC53E.1010509@mail.berlios.de> Date: Thu, 23 Sep 2010 23:23:10 +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> 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: Blue Swirl Cc: Kevin Wolf , QEMU Developers 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. Any preferences? I tend to (2), but that change is less local.