From e012b78cf5bc42f20ef1a1f78383035f2293ceea Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Wed, 17 Dec 2014 16:09:59 +0100 Subject: [PATCH] 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 Signed-off-by: Kevin Wolf --- block.c | 12 +++++------- 1 file 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);