Message ID | 1389968119-24771-11-git-send-email-kwolf@redhat.com |
---|---|
State | New |
Headers | show |
On 17.01.2014 15:15, Kevin Wolf wrote: > 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. > > Signed-off-by: Kevin Wolf <kwolf@redhat.com> > --- > block.c | 64 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++------ > 1 file changed, 58 insertions(+), 6 deletions(-) Together with patch 29: Reviewed-by: Max Reitz <mreitz@redhat.com>
Le Friday 17 Jan 2014 à 15:15:00 (+0100), Kevin Wolf a écrit : > 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. > > Signed-off-by: Kevin Wolf <kwolf@redhat.com> > --- > block.c | 64 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++------ > 1 file changed, 58 insertions(+), 6 deletions(-) > > 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 = bs->drv; > + /* TODO Lift BDRV_SECTOR_SIZE restriction in BlockDriver interface */ > + uint64_t align = MAX(BDRV_SECTOR_SIZE, bs->request_alignment); > + uint8_t *head_buf = NULL; > + uint8_t *tail_buf = NULL; > + QEMUIOVector local_qiov; > + bool use_local_qiov = false; > int ret; > > if (!drv) { > return -ENOMEDIUM; > } > - if (bdrv_check_request(bs, sector_num, nb_sectors)) { > + if (bdrv_check_byte_request(bs, offset, bytes)) { > return -EIO; > } > > @@ -2811,14 +2817,60 @@ static int coroutine_fn bdrv_co_do_readv(BlockDriverState *bs, > > /* 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 = 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 = true; > + > + bytes += offset & (align - 1); > + offset = 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 = true; > + } > + tail_buf = qemu_blockalign(bs, align); > + qemu_iovec_add(&local_qiov, tail_buf, > + align - ((offset + bytes) & (align - 1))); > + > + bytes = ROUND_UP(bytes, align); > + } > + > + ret = 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); > } > > - ret = bdrv_aligned_preadv(bs, sector_num << BDRV_SECTOR_BITS, > - nb_sectors << BDRV_SECTOR_BITS, qiov, flags); > return ret; > } > > +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, flags); > +} > + > int coroutine_fn bdrv_co_readv(BlockDriverState *bs, int64_t sector_num, > int nb_sectors, QEMUIOVector *qiov) > { > -- > 1.8.1.4 > > Reviewed-by: Benoit Canet <benoit@irqsave.net>
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 = bs->drv; + /* TODO Lift BDRV_SECTOR_SIZE restriction in BlockDriver interface */ + uint64_t align = MAX(BDRV_SECTOR_SIZE, bs->request_alignment); + uint8_t *head_buf = NULL; + uint8_t *tail_buf = NULL; + QEMUIOVector local_qiov; + bool use_local_qiov = false; int ret; if (!drv) { return -ENOMEDIUM; } - if (bdrv_check_request(bs, sector_num, nb_sectors)) { + if (bdrv_check_byte_request(bs, offset, bytes)) { return -EIO; } @@ -2811,14 +2817,60 @@ static int coroutine_fn bdrv_co_do_readv(BlockDriverState *bs, /* 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 = 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 = true; + + bytes += offset & (align - 1); + offset = 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 = true; + } + tail_buf = qemu_blockalign(bs, align); + qemu_iovec_add(&local_qiov, tail_buf, + align - ((offset + bytes) & (align - 1))); + + bytes = ROUND_UP(bytes, align); + } + + ret = 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); } - ret = bdrv_aligned_preadv(bs, sector_num << BDRV_SECTOR_BITS, - nb_sectors << BDRV_SECTOR_BITS, qiov, flags); return ret; } +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, flags); +} + int coroutine_fn bdrv_co_readv(BlockDriverState *bs, int64_t sector_num, int nb_sectors, QEMUIOVector *qiov) {
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. Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block.c | 64 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 58 insertions(+), 6 deletions(-)