From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49089) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YJebQ-0007gS-Bl for qemu-devel@nongnu.org; Fri, 06 Feb 2015 03:49:29 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YJebN-0000Z1-0o for qemu-devel@nongnu.org; Fri, 06 Feb 2015 03:49:28 -0500 Received: from mx-v6.kamp.de ([2a02:248:0:51::16]:46622 helo=mx01.kamp.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YJebM-0000YK-Hr for qemu-devel@nongnu.org; Fri, 06 Feb 2015 03:49:24 -0500 Message-ID: <54D48010.9000908@kamp.de> Date: Fri, 06 Feb 2015 09:49:20 +0100 From: Peter Lieven MIME-Version: 1.0 References: <1422965567-8611-1-git-send-email-pl@kamp.de> <54D0CD54.9080309@parallels.com> <54D0DB80.4070004@kamp.de> <54D0EA2D.2070900@parallels.com> In-Reply-To: <54D0EA2D.2070900@parallels.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] block: introduce BDRV_REQUEST_MAX_SECTORS List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Denis V. Lunev" , qemu-devel@nongnu.org Cc: kwolf@redhat.com Am 03.02.2015 um 16:33 schrieb Denis V. Lunev: > On 03/02/15 17:30, Peter Lieven wrote: >> Am 03.02.2015 um 14:29 schrieb Denis V. Lunev: >>> On 03/02/15 15:12, Peter Lieven wrote: >>>> we check and adjust request sizes at several places with >>>> sometimes inconsistent checks or default values: >>>> INT_MAX >>>> INT_MAX >> BDRV_SECTOR_BITS >>>> UINT_MAX >> BDRV_SECTOR_BITS >>>> SIZE_MAX >> BDRV_SECTOR_BITS >>>> >>>> This patches introdocues a macro for the maximal allowed sectors >>>> per request and uses it at several places. >>>> >>>> Signed-off-by: Peter Lieven >>>> --- >>>> block.c | 19 ++++++++----------- >>>> hw/block/virtio-blk.c | 4 ++-- >>>> include/block/block.h | 3 +++ >>>> 3 files changed, 13 insertions(+), 13 deletions(-) >>>> >>>> diff --git a/block.c b/block.c >>>> index 8272ef9..4e58b35 100644 >>>> --- a/block.c >>>> +++ b/block.c >>>> @@ -2671,7 +2671,7 @@ static int bdrv_check_byte_request(BlockDriverState *bs, int64_t offset, >>>> static int bdrv_check_request(BlockDriverState *bs, int64_t sector_num, >>>> int nb_sectors) >>>> { >>>> - if (nb_sectors < 0 || nb_sectors > INT_MAX / BDRV_SECTOR_SIZE) { >>>> + if (nb_sectors < 0 || nb_sectors > BDRV_REQUEST_MAX_SECTORS) { >>>> return -EIO; >>>> } >>>> @@ -2758,7 +2758,7 @@ static int bdrv_rw_co(BlockDriverState *bs, int64_t sector_num, uint8_t *buf, >>>> .iov_len = nb_sectors * BDRV_SECTOR_SIZE, >>>> }; >>>> - if (nb_sectors < 0 || nb_sectors > INT_MAX / BDRV_SECTOR_SIZE) { >>>> + if (nb_sectors < 0 || nb_sectors > BDRV_REQUEST_MAX_SECTORS) { >>>> return -EINVAL; >>>> } >>>> @@ -2826,13 +2826,10 @@ int bdrv_make_zero(BlockDriverState *bs, BdrvRequestFlags flags) >>>> } >>>> for (;;) { >>>> - nb_sectors = target_sectors - sector_num; >>>> + nb_sectors = MIN(target_sectors - sector_num, BDRV_REQUEST_MAX_SECTORS); >>>> if (nb_sectors <= 0) { >>>> return 0; >>>> } >>>> - if (nb_sectors > INT_MAX / BDRV_SECTOR_SIZE) { >>>> - nb_sectors = INT_MAX / BDRV_SECTOR_SIZE; >>>> - } >>>> ret = bdrv_get_block_status(bs, sector_num, nb_sectors, &n); >>>> if (ret < 0) { >>>> error_report("error getting block status at sector %" PRId64 ": %s", >>>> @@ -3167,7 +3164,7 @@ static int coroutine_fn bdrv_co_do_readv(BlockDriverState *bs, >>>> int64_t sector_num, int nb_sectors, QEMUIOVector *qiov, >>>> BdrvRequestFlags flags) >>>> { >>>> - if (nb_sectors < 0 || nb_sectors > (UINT_MAX >> BDRV_SECTOR_BITS)) { >>>> + if (nb_sectors < 0 || nb_sectors > BDRV_REQUEST_MAX_SECTORS) { >>>> return -EINVAL; >>>> } >>>> @@ -3202,8 +3199,8 @@ static int coroutine_fn bdrv_co_do_write_zeroes(BlockDriverState *bs, >>>> struct iovec iov = {0}; >>>> int ret = 0; >>>> - int max_write_zeroes = bs->bl.max_write_zeroes ? >>>> - bs->bl.max_write_zeroes : INT_MAX; >>>> + int max_write_zeroes = MIN_NON_ZERO(bs->bl.max_write_zeroes, >>>> + BDRV_REQUEST_MAX_SECTORS); >>>> while (nb_sectors > 0 && !ret) { >>>> int num = nb_sectors; >>>> @@ -3458,7 +3455,7 @@ 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 > BDRV_REQUEST_MAX_SECTORS) { >>>> return -EINVAL; >>>> } >>>> @@ -5120,7 +5117,7 @@ int coroutine_fn bdrv_co_discard(BlockDriverState *bs, int64_t sector_num, >>>> return 0; >>>> } >>>> - max_discard = bs->bl.max_discard ? bs->bl.max_discard : INT_MAX; >>>> + max_discard = MIN_NON_ZERO(bs->bl.max_discard, BDRV_REQUEST_MAX_SECTORS); >>>> while (nb_sectors > 0) { >>>> int ret; >>>> int num = nb_sectors; >>>> diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c >>>> index 8c51a29..1a8a176 100644 >>>> --- a/hw/block/virtio-blk.c >>>> +++ b/hw/block/virtio-blk.c >>>> @@ -381,7 +381,7 @@ void virtio_blk_submit_multireq(BlockBackend *blk, MultiReqBuffer *mrb) >>>> } >>>> max_xfer_len = blk_get_max_transfer_length(mrb->reqs[0]->dev->blk); >>>> - max_xfer_len = MIN_NON_ZERO(max_xfer_len, INT_MAX); >>>> + max_xfer_len = MIN_NON_ZERO(max_xfer_len, BDRV_REQUEST_MAX_SECTORS); >>>> qsort(mrb->reqs, mrb->num_reqs, sizeof(*mrb->reqs), >>>> &multireq_compare); >>>> @@ -447,7 +447,7 @@ static bool virtio_blk_sect_range_ok(VirtIOBlock *dev, >>>> uint64_t nb_sectors = size >> BDRV_SECTOR_BITS; >>>> uint64_t total_sectors; >>>> - if (nb_sectors > INT_MAX) { >>>> + if (nb_sectors > BDRV_REQUEST_MAX_SECTORS) { >>>> return false; >>>> } >>>> if (sector & dev->sector_mask) { >>>> diff --git a/include/block/block.h b/include/block/block.h >>>> index 3082d2b..25a6d62 100644 >>>> --- a/include/block/block.h >>>> +++ b/include/block/block.h >>>> @@ -83,6 +83,9 @@ typedef enum { >>>> #define BDRV_SECTOR_SIZE (1ULL << BDRV_SECTOR_BITS) >>>> #define BDRV_SECTOR_MASK ~(BDRV_SECTOR_SIZE - 1) >>>> +#define BDRV_REQUEST_MAX_SECTORS MIN(SIZE_MAX >> BDRV_SECTOR_BITS, \ >>>> + INT_MAX >> BDRV_SECTOR_BITS) >>>> + >>>> /* >>>> * Allocation status flags >>>> * BDRV_BLOCK_DATA: data is read from bs->file or another file >>> Reviewed-by: Denis V. Lunev >>> >>> On the other hand the limitation to INT_MAX for a request size >>> (in bytes) is here. >>> >>> bdrv_check_byte_request >>> if (size > INT_MAX) { >>> return -EIO; >>> } >>> >>> which means that all my patches from series >>> [PATCH v3 0/2] fix max_discard for NBD/gluster block drivers >>> becomes unnecessary but this was not that obvious before this >>> clarification :) >> >> No, not completely. If we run into the check above the request fails. >> If you set max_write_zeroes the request is appropiately trimmed. >> So if the driver allows less than BDRV_REQUEST_MAX_SECTORS sectors >> you still have to set it in the BlockLimits. >> >> Peter >> > your point will be correct after the following patch applied > > diff --git a/block.c b/block.c > index 4e58b35..49e0073 100644 > --- a/block.c > +++ b/block.c > @@ -2647,7 +2647,7 @@ static int bdrv_check_byte_request(BlockDriverState *bs, i > { > int64_t len; > > - if (size > INT_MAX) { > + if (size > BDRV_REQUEST_MAX_SECTORS << BDRV_SECTOR_BITS) { > return -EIO; > } You are right, this will still fail if SIZE_MAX < INT_MAX. I would send a v2 of my patch and add the above. Then Kevin can remove your 2 patches, right? Peter > > without we will fail at entry point inside bdrv_check_byte_request(). > My patch applies the limit of UINT32_MAX over the value which > is not greater than INT_MAX in the current codebase. > bdrv_check_byte_request() is performed at the very-very beginning > of the processing, f.e > > bdrv_co_discard > bdrv_check_request > bdrv_check_byte_request <-- (INT_MAX limit applied) > max_discard = MIN_NON_ZERO(bs->bl.max_discard, BDRV_REQUEST_MAX_SECTORS); > > Den