| Message ID | 20190320162633.29479-1-paul.durrant@citrix.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | xen-block: scale sector based quantities correctly | expand |
On Wed, Mar 20, 2019 at 04:26:32PM +0000, Paul Durrant wrote: > The mail thread at [1] clarifies that the Xen blkif protocol requires that > sector based quantities should be interpreted strictly as multiples of > 512 bytes. This patch modifies the xen-block code accordingly. > > [1] https://lists.xenproject.org/archives/html/xen-devel/2019-03/msg01600.html So, that patch [1] only makes one change: how to interpret the "sectors" node. It doesn't change the unit of a sector in blkif_request and blkif_request_segment. For a request, there is a comment in blkif.h: NB. first_sect and last_sect in blkif_request_segment, as well as sector_number in blkif_request, are always expressed in 512-byte units. I think most of this QEMU patch is to comply with that comment and would be a bug fix, but the single line change in hw/block/xen-block.c is different. > diff --git a/hw/block/xen-block.c b/hw/block/xen-block.c > index a848849f48..57e9da7e1c 100644 > --- a/hw/block/xen-block.c > +++ b/hw/block/xen-block.c > @@ -149,7 +149,7 @@ static void xen_block_set_size(XenBlockDevice *blockdev) > const char *type = object_get_typename(OBJECT(blockdev)); > XenBlockVdev *vdev = &blockdev->props.vdev; > BlockConf *conf = &blockdev->props.conf; > - int64_t sectors = blk_getlength(conf->blk) / conf->logical_block_size; > + int64_t sectors = blk_getlength(conf->blk) / XEN_BLKIF_SECTOR_SIZE; That the only thing that the thread [1] is changing. > XenDevice *xendev = XEN_DEVICE(blockdev); > > trace_xen_block_size(type, vdev->disk, vdev->partition, sectors); Thanks,
> -----Original Message----- > From: Anthony PERARD [mailto:anthony.perard@citrix.com] > Sent: 21 March 2019 15:00 > To: Paul Durrant <Paul.Durrant@citrix.com> > Cc: xen-devel@lists.xenproject.org; qemu-block@nongnu.org; qemu-devel@nongnu.org; Stefan Hajnoczi > <stefanha@redhat.com>; Stefano Stabellini <sstabellini@kernel.org>; Kevin Wolf <kwolf@redhat.com>; Max > Reitz <mreitz@redhat.com> > Subject: Re: [PATCH] xen-block: scale sector based quantities correctly > > On Wed, Mar 20, 2019 at 04:26:32PM +0000, Paul Durrant wrote: > > The mail thread at [1] clarifies that the Xen blkif protocol requires that > > sector based quantities should be interpreted strictly as multiples of > > 512 bytes. This patch modifies the xen-block code accordingly. > > > > [1] https://lists.xenproject.org/archives/html/xen-devel/2019-03/msg01600.html > > So, that patch [1] only makes one change: how to interpret the "sectors" > node. It doesn't change the unit of a sector in blkif_request and > blkif_request_segment. > > For a request, there is a comment in blkif.h: > NB. first_sect and last_sect in blkif_request_segment, as well as > sector_number in blkif_request, are always expressed in 512-byte units. > > I think most of this QEMU patch is to comply with that comment and would > be a bug fix, but the single line change in hw/block/xen-block.c is > different. > > > diff --git a/hw/block/xen-block.c b/hw/block/xen-block.c > > index a848849f48..57e9da7e1c 100644 > > --- a/hw/block/xen-block.c > > +++ b/hw/block/xen-block.c > > @@ -149,7 +149,7 @@ static void xen_block_set_size(XenBlockDevice *blockdev) > > const char *type = object_get_typename(OBJECT(blockdev)); > > XenBlockVdev *vdev = &blockdev->props.vdev; > > BlockConf *conf = &blockdev->props.conf; > > - int64_t sectors = blk_getlength(conf->blk) / conf->logical_block_size; > > + int64_t sectors = blk_getlength(conf->blk) / XEN_BLKIF_SECTOR_SIZE; > > That the only thing that the thread [1] is changing. > Ok, true. I'll split this up into two patches then. Paul > > XenDevice *xendev = XEN_DEVICE(blockdev); > > > > trace_xen_block_size(type, vdev->disk, vdev->partition, sectors); > > Thanks, > > -- > Anthony PERARD
diff --git a/hw/block/dataplane/xen-block.c b/hw/block/dataplane/xen-block.c index f1523c5b45..bb8f1186e4 100644 --- a/hw/block/dataplane/xen-block.c +++ b/hw/block/dataplane/xen-block.c @@ -49,7 +49,6 @@ struct XenBlockDataPlane { unsigned int *ring_ref; unsigned int nr_ring_ref; void *sring; - int64_t file_blk; int protocol; blkif_back_rings_t rings; int more_work; @@ -168,7 +167,7 @@ static int xen_block_parse_request(XenBlockRequest *request) goto err; } - request->start = request->req.sector_number * dataplane->file_blk; + request->start = request->req.sector_number * XEN_BLKIF_SECTOR_SIZE; for (i = 0; i < request->req.nr_segments; i++) { if (i == BLKIF_MAX_SEGMENTS_PER_REQUEST) { error_report("error: nr_segments too big"); @@ -178,14 +177,14 @@ static int xen_block_parse_request(XenBlockRequest *request) error_report("error: first > last sector"); goto err; } - if (request->req.seg[i].last_sect * dataplane->file_blk >= + if (request->req.seg[i].last_sect * XEN_BLKIF_SECTOR_SIZE >= XC_PAGE_SIZE) { error_report("error: page crossing"); goto err; } len = (request->req.seg[i].last_sect - - request->req.seg[i].first_sect + 1) * dataplane->file_blk; + request->req.seg[i].first_sect + 1) * XEN_BLKIF_SECTOR_SIZE; request->size += len; } if (request->start + request->size > blk_getlength(dataplane->blk)) { @@ -205,7 +204,6 @@ static int xen_block_copy_request(XenBlockRequest *request) XenDevice *xendev = dataplane->xendev; XenDeviceGrantCopySegment segs[BLKIF_MAX_SEGMENTS_PER_REQUEST]; int i, count; - int64_t file_blk = dataplane->file_blk; bool to_domain = (request->req.operation == BLKIF_OP_READ); void *virt = request->buf; Error *local_err = NULL; @@ -220,16 +218,17 @@ static int xen_block_copy_request(XenBlockRequest *request) if (to_domain) { segs[i].dest.foreign.ref = request->req.seg[i].gref; segs[i].dest.foreign.offset = request->req.seg[i].first_sect * - file_blk; + XEN_BLKIF_SECTOR_SIZE; segs[i].source.virt = virt; } else { segs[i].source.foreign.ref = request->req.seg[i].gref; segs[i].source.foreign.offset = request->req.seg[i].first_sect * - file_blk; + XEN_BLKIF_SECTOR_SIZE; segs[i].dest.virt = virt; } segs[i].len = (request->req.seg[i].last_sect - - request->req.seg[i].first_sect + 1) * file_blk; + request->req.seg[i].first_sect + 1) * + XEN_BLKIF_SECTOR_SIZE; virt += segs[i].len; } @@ -331,22 +330,22 @@ static bool xen_block_split_discard(XenBlockRequest *request, XenBlockDataPlane *dataplane = request->dataplane; int64_t byte_offset; int byte_chunk; - uint64_t byte_remaining, limit; + uint64_t byte_remaining; uint64_t sec_start = sector_number; uint64_t sec_count = nr_sectors; /* Wrap around, or overflowing byte limit? */ if (sec_start + sec_count < sec_count || - sec_start + sec_count > INT64_MAX / dataplane->file_blk) { + sec_start + sec_count > INT64_MAX / XEN_BLKIF_SECTOR_SIZE) { return false; } - limit = BDRV_REQUEST_MAX_SECTORS * dataplane->file_blk; - byte_offset = sec_start * dataplane->file_blk; - byte_remaining = sec_count * dataplane->file_blk; + byte_offset = sec_start * XEN_BLKIF_SECTOR_SIZE; + byte_remaining = sec_count * XEN_BLKIF_SECTOR_SIZE; do { - byte_chunk = byte_remaining > limit ? limit : byte_remaining; + byte_chunk = byte_remaining > BDRV_REQUEST_MAX_BYTES ? + BDRV_REQUEST_MAX_BYTES : byte_remaining; request->aio_inflight++; blk_aio_pdiscard(dataplane->blk, byte_offset, byte_chunk, xen_block_complete_aio, request); @@ -632,7 +631,6 @@ XenBlockDataPlane *xen_block_dataplane_create(XenDevice *xendev, XenBlockDataPlane *dataplane = g_new0(XenBlockDataPlane, 1); dataplane->xendev = xendev; - dataplane->file_blk = conf->logical_block_size; dataplane->blk = conf->blk; QLIST_INIT(&dataplane->inflight); diff --git a/hw/block/xen-block.c b/hw/block/xen-block.c index a848849f48..57e9da7e1c 100644 --- a/hw/block/xen-block.c +++ b/hw/block/xen-block.c @@ -149,7 +149,7 @@ static void xen_block_set_size(XenBlockDevice *blockdev) const char *type = object_get_typename(OBJECT(blockdev)); XenBlockVdev *vdev = &blockdev->props.vdev; BlockConf *conf = &blockdev->props.conf; - int64_t sectors = blk_getlength(conf->blk) / conf->logical_block_size; + int64_t sectors = blk_getlength(conf->blk) / XEN_BLKIF_SECTOR_SIZE; XenDevice *xendev = XEN_DEVICE(blockdev); trace_xen_block_size(type, vdev->disk, vdev->partition, sectors); diff --git a/hw/block/xen_blkif.h b/hw/block/xen_blkif.h index 3e6e1ea365..a353693ea0 100644 --- a/hw/block/xen_blkif.h +++ b/hw/block/xen_blkif.h @@ -143,4 +143,6 @@ static inline void blkif_get_x86_64_req(blkif_request_t *dst, } } +#define XEN_BLKIF_SECTOR_SIZE 512 + #endif /* XEN_BLKIF_H */
The mail thread at [1] clarifies that the Xen blkif protocol requires that sector based quantities should be interpreted strictly as multiples of 512 bytes. This patch modifies the xen-block code accordingly. [1] https://lists.xenproject.org/archives/html/xen-devel/2019-03/msg01600.html Signed-off-by: Paul Durrant <paul.durrant@citrix.com> --- Cc: Stefan Hajnoczi <stefanha@redhat.com> Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Anthony Perard <anthony.perard@citrix.com> Cc: Kevin Wolf <kwolf@redhat.com> Cc: Max Reitz <mreitz@redhat.com> --- hw/block/dataplane/xen-block.c | 28 +++++++++++++--------------- hw/block/xen-block.c | 2 +- hw/block/xen_blkif.h | 2 ++ 3 files changed, 16 insertions(+), 16 deletions(-)