From 222565f65c3fba6825912c2561de7831e514ef3c Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Thu, 9 Jul 2015 10:56:46 +0100 Subject: [PATCH] block: replace IOV_MAX with BlockLimits.max_iov Request merging must not result in a huge request that exceeds the maximum number of iovec elements. Use BlockLimits.max_iov instead of hardcoding IOV_MAX. Signed-off-by: Stefan Hajnoczi --- block/io.c | 3 ++- hw/block/virtio-blk.c | 2 +- 2 files changed, 3 insertions(+), 2 deletions(-) diff --git a/block/io.c b/block/io.c index 42050a0598..63e3678036 100644 --- a/block/io.c +++ b/block/io.c @@ -1889,7 +1889,8 @@ static int multiwrite_merge(BlockDriverState *bs, BlockRequest *reqs, merge = 1; } - if (reqs[outidx].qiov->niov + reqs[i].qiov->niov + 1 > IOV_MAX) { + if (reqs[outidx].qiov->niov + reqs[i].qiov->niov + 1 > + bs->bl.max_iov) { merge = 0; } diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c index f72d4b6069..51f867b513 100644 --- a/hw/block/virtio-blk.c +++ b/hw/block/virtio-blk.c @@ -414,7 +414,7 @@ void virtio_blk_submit_multireq(BlockBackend *blk, MultiReqBuffer *mrb) * 3. merge would exceed maximum transfer length of backend device */ if (sector_num + nb_sectors != req->sector_num || - niov > IOV_MAX - req->qiov.niov || + niov > blk_get_max_iov(blk) - req->qiov.niov || req->qiov.size / BDRV_SECTOR_SIZE > max_xfer_len || nb_sectors > max_xfer_len - req->qiov.size / BDRV_SECTOR_SIZE) { submit_requests(blk, mrb, start, num_reqs, niov);