From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54643) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W5b8i-00033W-8Y for qemu-devel@nongnu.org; Tue, 21 Jan 2014 08:13:18 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1W5b8Z-00041p-3L for qemu-devel@nongnu.org; Tue, 21 Jan 2014 08:13:12 -0500 Received: from paradis.irqsave.net ([62.212.105.220]:47940) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W5b8Y-00041c-Ij for qemu-devel@nongnu.org; Tue, 21 Jan 2014 08:13:03 -0500 Date: Tue, 21 Jan 2014 14:13:01 +0100 From: =?iso-8859-1?Q?Beno=EEt?= Canet Message-ID: <20140121131300.GD9834@irqsave.net> References: <1389968119-24771-1-git-send-email-kwolf@redhat.com> <1389968119-24771-10-git-send-email-kwolf@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <1389968119-24771-10-git-send-email-kwolf@redhat.com> Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH v3 09/29] block: Introduce bdrv_aligned_preadv() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Kevin Wolf Cc: pl@kamp.de, qemu-devel@nongnu.org, mreitz@redhat.com, stefanha@redhat.com, pbonzini@redhat.com, xiawenc@linux.vnet.ibm.com Le Friday 17 Jan 2014 =E0 15:14:59 (+0100), Kevin Wolf a =E9crit : > This separates the part of bdrv_co_do_readv() that needs to happen > before the request is modified to match the backend alignment, and a > part that needs to be executed afterwards and passes the request to the > BlockDriver. >=20 > Signed-off-by: Kevin Wolf > Reviewed-by: Wenchao Xia > Reviewed-by: Max Reitz > --- > block.c | 61 +++++++++++++++++++++++++++++++++++++++++++--------------= ---- > 1 file changed, 43 insertions(+), 18 deletions(-) >=20 > diff --git a/block.c b/block.c > index 25ae896..0c2baf5 100644 > --- a/block.c > +++ b/block.c > @@ -2705,26 +2705,24 @@ err: > } > =20 > /* > - * Handle a read request in coroutine context > + * Forwards an already correctly aligned request to the BlockDriver. T= his > + * handles copy on read and zeroing after EOF; any other features must= be > + * implemented by the caller. > */ > -static int coroutine_fn bdrv_co_do_readv(BlockDriverState *bs, > - int64_t sector_num, int nb_sectors, QEMUIOVector *qiov, > - BdrvRequestFlags flags) > +static int coroutine_fn bdrv_aligned_preadv(BlockDriverState *bs, > + int64_t offset, unsigned int bytes, QEMUIOVector *qiov, int flags) unsigned int bytes <- Would it worth it to make this int64_t or size_t fo= r the not so far future where 4GB will be the new 4MB ? Best regards Beno=EEt > { > BlockDriver *drv =3D bs->drv; > BdrvTrackedRequest req; > int ret; > =20 > - if (!drv) { > - return -ENOMEDIUM; > - } > - if (bdrv_check_request(bs, sector_num, nb_sectors)) { > - return -EIO; > - } > + int64_t sector_num =3D offset >> BDRV_SECTOR_BITS; > + unsigned int nb_sectors =3D bytes >> BDRV_SECTOR_BITS; > =20 > - if (bs->copy_on_read) { > - flags |=3D BDRV_REQ_COPY_ON_READ; > - } > + assert((offset & (BDRV_SECTOR_SIZE - 1)) =3D=3D 0); > + assert((bytes & (BDRV_SECTOR_SIZE - 1)) =3D=3D 0); > + > + /* Handle Copy on Read and associated serialisation */ > if (flags & BDRV_REQ_COPY_ON_READ) { > bs->copy_on_read_in_flight++; > } > @@ -2733,11 +2731,6 @@ static int coroutine_fn bdrv_co_do_readv(BlockDr= iverState *bs, > wait_for_overlapping_requests(bs, sector_num, nb_sectors); > } > =20 > - /* throttling disk I/O */ > - if (bs->io_limits_enabled) { > - bdrv_io_limits_intercept(bs, nb_sectors, false); > - } > - > tracked_request_begin(&req, bs, sector_num, nb_sectors, false); > =20 > if (flags & BDRV_REQ_COPY_ON_READ) { > @@ -2754,6 +2747,7 @@ static int coroutine_fn bdrv_co_do_readv(BlockDri= verState *bs, > } > } > =20 > + /* Forward the request to the BlockDriver */ > if (!(bs->zero_beyond_eof && bs->growable)) { > ret =3D drv->bdrv_co_readv(bs, sector_num, nb_sectors, qiov); > } else { > @@ -2794,6 +2788,37 @@ out: > return ret; > } > =20 > +/* > + * Handle a read request in coroutine context > + */ > +static int coroutine_fn bdrv_co_do_readv(BlockDriverState *bs, > + int64_t sector_num, int nb_sectors, QEMUIOVector *qiov, > + BdrvRequestFlags flags) > +{ > + BlockDriver *drv =3D bs->drv; > + int ret; > + > + if (!drv) { > + return -ENOMEDIUM; > + } > + if (bdrv_check_request(bs, sector_num, nb_sectors)) { > + return -EIO; > + } > + > + if (bs->copy_on_read) { > + flags |=3D BDRV_REQ_COPY_ON_READ; > + } > + > + /* throttling disk I/O */ > + if (bs->io_limits_enabled) { > + bdrv_io_limits_intercept(bs, nb_sectors, false); > + } > + > + ret =3D bdrv_aligned_preadv(bs, sector_num << BDRV_SECTOR_BITS, > + nb_sectors << BDRV_SECTOR_BITS, qiov, fla= gs); > + return ret; > +} > + > int coroutine_fn bdrv_co_readv(BlockDriverState *bs, int64_t sector_nu= m, > int nb_sectors, QEMUIOVector *qiov) > { > --=20 > 1.8.1.4 >=20 >=20