mirror: limit niov to IOV_MAX elements, again

During the refactor of mirror_iteration in e5b43573,
we regressed the fix introduced in cae98cb8.

This patch re-adds IOV_MAX checking to cases where we
aren't checking alignment (and size) already.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-id: 1466625064-11280-3-git-send-email-jsnow@redhat.com
Signed-off-by: Jeff Cody <jcody@redhat.com>

diff --git a/block/mirror.c b/block/mirror.c
index 42ebc3b9e9eea8f5c5dd350081d9fb1f2135263d..5bac906d82fb3c8263adbbcbb8ac0bd1258ac0e3 100644 (file)
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -231,11 +231,14 @@ static int mirror_do_read(MirrorBlockJob *s, int64_t sector_num,
     int sectors_per_chunk, nb_chunks;
     int ret;
     MirrorOp *op;
+    int max_sectors;
 
     sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS;
+    max_sectors = sectors_per_chunk * s->max_iov;
 
     /* We can only handle as much as buf_size at a time. */
     nb_sectors = MIN(s->buf_size >> BDRV_SECTOR_BITS, nb_sectors);
+    nb_sectors = MIN(max_sectors, nb_sectors);
     assert(nb_sectors);
     ret = nb_sectors;