From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49550) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZrNR8-0006Tq-M5 for qemu-devel@nongnu.org; Wed, 28 Oct 2015 05:54:31 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZrNR7-00043Q-LO for qemu-devel@nongnu.org; Wed, 28 Oct 2015 05:54:30 -0400 Date: Wed, 28 Oct 2015 10:54:21 +0100 From: Kevin Wolf Message-ID: <20151028095421.GD3836@noname.str.redhat.com> References: <1445840693-3177-1-git-send-email-famz@redhat.com> <1445840693-3177-4-git-send-email-famz@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1445840693-3177-4-git-send-email-famz@redhat.com> Subject: Re: [Qemu-devel] [PATCH 3/9] block: Track discard requests List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Fam Zheng Cc: Stefan Hajnoczi , qemu-block@nongnu.org, Peter Lieven , qemu-devel@nongnu.org, Ronnie Sahlberg , Paolo Bonzini Am 26.10.2015 um 07:24 hat Fam Zheng geschrieben: > Both bdrv_discard and bdrv_aio_discard will call into bdrv_co_discard, > so add tracked_request_begin/end calls around the loop. > > Signed-off-by: Fam Zheng > --- > block/io.c | 14 ++++++++++---- > 1 file changed, 10 insertions(+), 4 deletions(-) > > diff --git a/block/io.c b/block/io.c > index 223c4e9..abb3aaa 100644 > --- a/block/io.c > +++ b/block/io.c > @@ -2415,7 +2415,8 @@ static void coroutine_fn bdrv_discard_co_entry(void *opaque) > int coroutine_fn bdrv_co_discard(BlockDriverState *bs, int64_t sector_num, > int nb_sectors) > { > - int max_discard, ret; > + BdrvTrackedRequest req; > + int max_discard, ret = 0; > > if (!bs->drv) { > return -ENOMEDIUM; > @@ -2437,6 +2438,8 @@ int coroutine_fn bdrv_co_discard(BlockDriverState *bs, int64_t sector_num, > return 0; > } > > + tracked_request_begin(&req, bs, sector_num, nb_sectors, > + BDRV_TRACKED_DISCARD); > bdrv_set_dirty(bs, sector_num, nb_sectors); > > max_discard = MIN_NON_ZERO(bs->bl.max_discard, BDRV_REQUEST_MAX_SECTORS); > @@ -2470,20 +2473,23 @@ int coroutine_fn bdrv_co_discard(BlockDriverState *bs, int64_t sector_num, > acb = bs->drv->bdrv_aio_discard(bs, sector_num, nb_sectors, > bdrv_co_io_em_complete, &co); > if (acb == NULL) { > - return -EIO; > + ret = -EIO; > + goto out; > } else { > qemu_coroutine_yield(); > ret = co.ret; > } > } > if (ret && ret != -ENOTSUP) { > - return ret; > + goto out; > } > > sector_num += num; > nb_sectors -= num; > } > - return 0; > +out: > + tracked_request_end(&req); > + return ret; > } I would prefer an explicit ret = 0 before the out label because otherwise you're relying on the previous value that has been set somewhere in the loop. As far as I can tell, it's still correct, but it makes it needlessly hard to tell whether success is 0 or >= 0. Kevin