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Re: [Qemu-devel] [Xen-devel] [PATCH] xen: fix qdisk BLKIF_OP_DISCARD for
From: |
Paul Durrant |
Subject: |
Re: [Qemu-devel] [Xen-devel] [PATCH] xen: fix qdisk BLKIF_OP_DISCARD for 32/64 word size mix |
Date: |
Thu, 16 Jun 2016 11:24:38 +0000 |
> -----Original Message-----
> From: Xen-devel [mailto:address@hidden On Behalf Of
> Juergen Gross
> Sent: 16 June 2016 11:02
> To: address@hidden; address@hidden
> Cc: Anthony Perard; Juergen Gross; address@hidden;
> address@hidden
> Subject: [Xen-devel] [PATCH] xen: fix qdisk BLKIF_OP_DISCARD for 32/64
> word size mix
>
> In case the word size of the domU and qemu running the qdisk backend
> differ BLKIF_OP_DISCARD will not work reliably, as the request
> structure in the ring have different layouts for different word size.
>
> Correct this by copying the request structure in case of different
> word size element by element in the BLKIF_OP_DISCARD case, too.
>
> Signed-off-by: Juergen Gross <address@hidden>
Would it not be better to re-import the canonical blkif header as a whole
rather than cherry-picking like this? You'd need to post-process to maintain
style and possibly change some names for compatibility etc. but probably
nothing beyond what indent and a simple [s]ed script can do.
I did broadly the same thing to re-import the netif header into Linux recently.
Paul
> ---
> hw/block/xen_blkif.h | 20 ++++++++++++++++++--
> 1 file changed, 18 insertions(+), 2 deletions(-)
>
> diff --git a/hw/block/xen_blkif.h b/hw/block/xen_blkif.h
> index e3b133b..969112f 100644
> --- a/hw/block/xen_blkif.h
> +++ b/hw/block/xen_blkif.h
> @@ -26,6 +26,14 @@ struct blkif_x86_32_request {
> blkif_sector_t sector_number;/* start sector idx on disk (r/w only)
> */
> struct blkif_request_segment
> seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
> };
> +struct blkif_x86_32_request_discard {
> + uint8_t operation; /* BLKIF_OP_DISCARD */
> + uint8_t flag; /* nr_segments in request struct */
> + blkif_vdev_t handle; /* only for read/write requests */
> + uint64_t id; /* private guest value, echoed in resp */
> + blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
> + uint64_t nr_sectors; /* # of contiguous sectors to discard */
> +};
> struct blkif_x86_32_response {
> uint64_t id; /* copied from request */
> uint8_t operation; /* copied from request */
> @@ -44,6 +52,14 @@ struct blkif_x86_64_request {
> blkif_sector_t sector_number;/* start sector idx on disk (r/w only)
> */
> struct blkif_request_segment
> seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
> };
> +struct blkif_x86_64_request_discard {
> + uint8_t operation; /* BLKIF_OP_DISCARD */
> + uint8_t flag; /* nr_segments in request struct */
> + blkif_vdev_t handle; /* only for read/write requests */
> + uint64_t __attribute__((__aligned__(8))) id;
> + blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
> + uint64_t nr_sectors; /* # of contiguous sectors to discard */
> +};
> struct blkif_x86_64_response {
> uint64_t __attribute__((__aligned__(8))) id;
> uint8_t operation; /* copied from request */
> @@ -82,7 +98,7 @@ static inline void blkif_get_x86_32_req(blkif_request_t
> *dst, blkif_x86_32_reque
> /* Prevent the compiler from using src->... instead. */
> barrier();
> if (dst->operation == BLKIF_OP_DISCARD) {
> - struct blkif_request_discard *s = (void *)src;
> + struct blkif_x86_32_request_discard *s = (void *)src;
> struct blkif_request_discard *d = (void *)dst;
> d->nr_sectors = s->nr_sectors;
> return;
> @@ -105,7 +121,7 @@ static inline void
> blkif_get_x86_64_req(blkif_request_t *dst, blkif_x86_64_reque
> /* Prevent the compiler from using src->... instead. */
> barrier();
> if (dst->operation == BLKIF_OP_DISCARD) {
> - struct blkif_request_discard *s = (void *)src;
> + struct blkif_x86_64_request_discard *s = (void *)src;
> struct blkif_request_discard *d = (void *)dst;
> d->nr_sectors = s->nr_sectors;
> return;
> --
> 2.6.6
>
>
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> Xen-devel mailing list
> address@hidden
> http://lists.xen.org/xen-devel
Re: [Qemu-devel] [Xen-devel] [PATCH] xen: fix qdisk BLKIF_OP_DISCARD for 32/64 word size mix,
Paul Durrant <=