From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59010) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W5bOx-0007Ou-JQ for qemu-devel@nongnu.org; Tue, 21 Jan 2014 08:30:04 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1W5bOs-0000rJ-7b for qemu-devel@nongnu.org; Tue, 21 Jan 2014 08:29:59 -0500 Received: from paradis.irqsave.net ([62.212.105.220]:47944) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W5bOr-0000qo-Kj for qemu-devel@nongnu.org; Tue, 21 Jan 2014 08:29:54 -0500 Date: Tue, 21 Jan 2014 14:29:52 +0100 From: =?iso-8859-1?Q?Beno=EEt?= Canet Message-ID: <20140121132952.GE9834@irqsave.net> References: <1389968119-24771-1-git-send-email-kwolf@redhat.com> <1389968119-24771-11-git-send-email-kwolf@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <1389968119-24771-11-git-send-email-kwolf@redhat.com> Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH v3 10/29] block: Introduce bdrv_co_do_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 15:15:00 (+0100), Kevin Wolf a =E9crit : > Similar to bdrv_pread(), which aligns byte-aligned request to 512 byte > sectors, bdrv_co_do_preadv() takes a byte-aligned request and aligns it > to the alignment specified in bs->request_alignment. >=20 > Signed-off-by: Kevin Wolf > --- > block.c | 64 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++= +------ > 1 file changed, 58 insertions(+), 6 deletions(-) >=20 > diff --git a/block.c b/block.c > index 0c2baf5..f378a10 100644 > --- a/block.c > +++ b/block.c > @@ -2791,17 +2791,23 @@ out: > /* > * 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, > +static int coroutine_fn bdrv_co_do_preadv(BlockDriverState *bs, > + int64_t offset, unsigned int bytes, QEMUIOVector *qiov, > BdrvRequestFlags flags) > { > BlockDriver *drv =3D bs->drv; > + /* TODO Lift BDRV_SECTOR_SIZE restriction in BlockDriver interface= */ > + uint64_t align =3D MAX(BDRV_SECTOR_SIZE, bs->request_alignment); > + uint8_t *head_buf =3D NULL; > + uint8_t *tail_buf =3D NULL; > + QEMUIOVector local_qiov; > + bool use_local_qiov =3D false; > int ret; > =20 > if (!drv) { > return -ENOMEDIUM; > } > - if (bdrv_check_request(bs, sector_num, nb_sectors)) { > + if (bdrv_check_byte_request(bs, offset, bytes)) { > return -EIO; > } > =20 > @@ -2811,14 +2817,60 @@ static int coroutine_fn bdrv_co_do_readv(BlockD= riverState *bs, > =20 > /* throttling disk I/O */ > if (bs->io_limits_enabled) { > - bdrv_io_limits_intercept(bs, nb_sectors, false); > + /* TODO Switch to byte granularity */ > + bdrv_io_limits_intercept(bs, bytes >> BDRV_SECTOR_BITS, false)= ; > + } > + > + /* Align read if necessary by padding qiov */ > + if (offset & (align - 1)) { > + head_buf =3D qemu_blockalign(bs, align); > + qemu_iovec_init(&local_qiov, qiov->niov + 2); > + qemu_iovec_add(&local_qiov, head_buf, offset & (align - 1)); > + qemu_iovec_concat(&local_qiov, qiov, 0, qiov->size); > + use_local_qiov =3D true; > + > + bytes +=3D offset & (align - 1); > + offset =3D offset & ~(align - 1); > + } > + > + if ((offset + bytes) & (align - 1)) { > + if (!use_local_qiov) { > + qemu_iovec_init(&local_qiov, qiov->niov + 1); > + qemu_iovec_concat(&local_qiov, qiov, 0, qiov->size); > + use_local_qiov =3D true; > + } > + tail_buf =3D qemu_blockalign(bs, align); > + qemu_iovec_add(&local_qiov, tail_buf, > + align - ((offset + bytes) & (align - 1))); > + > + bytes =3D ROUND_UP(bytes, align); > + } > + > + ret =3D bdrv_aligned_preadv(bs, offset, bytes, > + use_local_qiov ? &local_qiov : qiov, > + flags); > + > + if (use_local_qiov) { > + qemu_iovec_destroy(&local_qiov); > + qemu_vfree(head_buf); > + qemu_vfree(tail_buf); > } > =20 > - ret =3D bdrv_aligned_preadv(bs, sector_num << BDRV_SECTOR_BITS, > - nb_sectors << BDRV_SECTOR_BITS, qiov, fla= gs); > return ret; > } > =20 > +static int coroutine_fn bdrv_co_do_readv(BlockDriverState *bs, > + int64_t sector_num, int nb_sectors, QEMUIOVector *qiov, > + BdrvRequestFlags flags) > +{ > + if (nb_sectors < 0 || nb_sectors > (UINT_MAX >> BDRV_SECTOR_BITS))= { > + return -EINVAL; > + } > + > + return bdrv_co_do_preadv(bs, sector_num << BDRV_SECTOR_BITS, > + nb_sectors << BDRV_SECTOR_BITS, qiov, fla= gs); > +} > + > 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 Reviewed-by: Benoit Canet