From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59830) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XwwIL-0003bE-WB for qemu-devel@nongnu.org; Fri, 05 Dec 2014 12:03:58 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XwwIG-0005jV-2U for qemu-devel@nongnu.org; Fri, 05 Dec 2014 12:03:53 -0500 Message-ID: <5481E566.8070108@redhat.com> Date: Fri, 05 Dec 2014 18:03:34 +0100 From: Max Reitz MIME-Version: 1.0 References: <1417796112-15141-1-git-send-email-ming.lei@canonical.com> In-Reply-To: <1417796112-15141-1-git-send-email-ming.lei@canonical.com> Content-Type: text/plain; charset=iso-8859-15; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] block: fix big write List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Ming Lei , qemu-devel@nongnu.org, Paolo Bonzini , Stefan Hajnoczi , Kevin Wolf Cc: Ming Lei , qemu-stable@nongnu.org On 2014-12-05 at 17:15, Ming Lei wrote: > From: Ming Lei > > QEMU block should have supported to read/write at most > 0x7fffff * 512 bytes, unfortunately INT_MAX is used to check > bytes in both bdrv_co_do_writev() and bdrv_check_byte_request(), > so cause write failure if nr_sectors is equal or more > than 0x400000. > > There are still other INT_MAX usages in block.c, and they might > need to change to UINT_MAX too in future, but at least > this patch's change can make SCSI WRITE SAME 16 workable. > > Cc: qemu-stable@nongnu.org > Signed-off-by: Ming Lei > --- > block.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/block.c b/block.c > index a612594..ddc18c2 100644 > --- a/block.c > +++ b/block.c > @@ -2607,7 +2607,7 @@ static int bdrv_check_byte_request(BlockDriverState *bs, int64_t offset, > { > int64_t len; > > - if (size > INT_MAX) { > + if (size > UINT_MAX) { > return -EIO; > } > > @@ -3420,7 +3420,7 @@ static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs, > int64_t sector_num, int nb_sectors, QEMUIOVector *qiov, > BdrvRequestFlags flags) > { > - if (nb_sectors < 0 || nb_sectors > (INT_MAX >> BDRV_SECTOR_BITS)) { > + if (nb_sectors < 0 || nb_sectors > (UINT_MAX >> BDRV_SECTOR_BITS)) { > return -EINVAL; > } > This is intentional so a byte length can be stored in an integer. This is a pretty bad design decision, but we have to live with it until we really fix the block layer regarding the type lengths are stored in. Max