aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorPaolo Bonzini <pbonzini@redhat.com>2014-12-17 16:09:59 +0100
committerStefan Hajnoczi <stefanha@redhat.com>2015-01-13 11:47:56 +0000
commite012b78cf5bc42f20ef1a1f78383035f2293ceea (patch)
treee4f047daaccf6c044eba955e7f68250902f2ff01
parentfcf5def1ab0f94ff120b7141c943b517d2ece83d (diff)
downloadqemu-arm-e012b78cf5bc42f20ef1a1f78383035f2293ceea.tar.gz
block: do not allocate an iovec per read of a growable/zero_after_eof BDS
Most reads do not go past the end of the file, and they can use the input QEMUIOVector instead of creating one. This removes the qemu_iovec_* functions from the profile. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
-rw-r--r--block.c12
1 files changed, 5 insertions, 7 deletions
diff --git a/block.c b/block.c
index 4165d4265c..58f804228c 100644
--- a/block.c
+++ b/block.c
@@ -3034,18 +3034,16 @@ static int coroutine_fn bdrv_aligned_preadv(BlockDriverState *bs,
max_nb_sectors = ROUND_UP(MAX(0, total_sectors - sector_num),
align >> BDRV_SECTOR_BITS);
- if (max_nb_sectors > 0) {
+ if (nb_sectors < max_nb_sectors) {
+ ret = drv->bdrv_co_readv(bs, sector_num, nb_sectors, qiov);
+ } else if (max_nb_sectors > 0) {
QEMUIOVector local_qiov;
- size_t local_sectors;
-
- max_nb_sectors = MIN(max_nb_sectors, SIZE_MAX / BDRV_SECTOR_BITS);
- local_sectors = MIN(max_nb_sectors, nb_sectors);
qemu_iovec_init(&local_qiov, qiov->niov);
qemu_iovec_concat(&local_qiov, qiov, 0,
- local_sectors * BDRV_SECTOR_SIZE);
+ max_nb_sectors * BDRV_SECTOR_SIZE);
- ret = drv->bdrv_co_readv(bs, sector_num, local_sectors,
+ ret = drv->bdrv_co_readv(bs, sector_num, max_nb_sectors,
&local_qiov);
qemu_iovec_destroy(&local_qiov);