From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35557) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YIeUv-0002h0-7z for qemu-devel@nongnu.org; Tue, 03 Feb 2015 09:30:38 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YIeUs-0002L1-Gv for qemu-devel@nongnu.org; Tue, 03 Feb 2015 09:30:37 -0500 Received: from mx-v6.kamp.de ([2a02:248:0:51::16]:39251 helo=mx01.kamp.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YIeUs-0002KS-6k for qemu-devel@nongnu.org; Tue, 03 Feb 2015 09:30:34 -0500 Message-ID: <54D0DB80.4070004@kamp.de> Date: Tue, 03 Feb 2015 15:30:24 +0100 From: Peter Lieven MIME-Version: 1.0 References: <1422965567-8611-1-git-send-email-pl@kamp.de> <54D0CD54.9080309@parallels.com> In-Reply-To: <54D0CD54.9080309@parallels.com> Content-Type: text/plain; charset=windows-1252; format=flowed 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 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