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authorEric Blake <eblake@redhat.com>2016-06-23 16:37:19 -0600
committerKevin Wolf <kwolf@redhat.com>2016-07-05 16:46:25 +0200
commit5def6b80e1eca696c1fc6099e7f4d36729686402 (patch)
tree5948b16242a3b57bb1dffa6c650ef05e9154f59e /hw/block/virtio-blk.c
parent79ba8c986adb9ca07f52abd0b3d33c3aee8e6ff9 (diff)
block: Switch transfer length bounds to byte-based
Sector-based limits are awkward to think about; in our on-going quest to move to byte-based interfaces, convert max_transfer_length and opt_transfer_length. Rename them (dropping the _length suffix) so that the compiler will help us catch the change in semantics across any rebased code, and improve the documentation. Use unsigned values, so that we don't have to worry about negative values and so that bit-twiddling is easier; however, we are still constrained by 2^31 of signed int in most APIs. When a value comes from an external source (iscsi and raw-posix), sanitize the results to ensure that opt_transfer is a power of 2. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'hw/block/virtio-blk.c')
-rw-r--r--hw/block/virtio-blk.c9
1 files changed, 5 insertions, 4 deletions
diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
index dd94cd4dc7..ae86e944ea 100644
--- a/hw/block/virtio-blk.c
+++ b/hw/block/virtio-blk.c
@@ -384,7 +384,7 @@ static int multireq_compare(const void *a, const void *b)
void virtio_blk_submit_multireq(BlockBackend *blk, MultiReqBuffer *mrb)
{
int i = 0, start = 0, num_reqs = 0, niov = 0, nb_sectors = 0;
- int max_xfer_len;
+ uint32_t max_transfer;
int64_t sector_num = 0;
if (mrb->num_reqs == 1) {
@@ -393,7 +393,7 @@ void virtio_blk_submit_multireq(BlockBackend *blk, MultiReqBuffer *mrb)
return;
}
- max_xfer_len = blk_get_max_transfer_length(mrb->reqs[0]->dev->blk);
+ max_transfer = blk_get_max_transfer(mrb->reqs[0]->dev->blk);
qsort(mrb->reqs, mrb->num_reqs, sizeof(*mrb->reqs),
&multireq_compare);
@@ -409,8 +409,9 @@ void virtio_blk_submit_multireq(BlockBackend *blk, MultiReqBuffer *mrb)
*/
if (sector_num + nb_sectors != req->sector_num ||
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) {
+ req->qiov.size > max_transfer ||
+ nb_sectors > (max_transfer -
+ req->qiov.size) / BDRV_SECTOR_SIZE) {
submit_requests(blk, mrb, start, num_reqs, niov);
num_reqs = 0;
}