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author | Rusty Russell <rusty@rustcorp.com.au> | 2013-03-20 06:14:26 +0100 |
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committer | Rusty Russell <rusty@rustcorp.com.au> | 2013-03-20 06:14:52 +0100 |
commit | 282edb36499042a92b71f052f51754ae7ed936e4 (patch) | |
tree | 5031caab94e52b30e48515e881ea87a32daaeaeb | |
parent | virtio_ring: virtqueue_add_sgs, to add multiple sgs. (diff) | |
download | linux-282edb36499042a92b71f052f51754ae7ed936e4.tar.xz linux-282edb36499042a92b71f052f51754ae7ed936e4.zip |
virtio_ring: virtqueue_add_outbuf / virtqueue_add_inbuf.
These are specialized versions of virtqueue_add_buf(), which cover
over 80% of cases and are far clearer.
In particular, the scatterlists passed to these functions don't have
to be clean (ie. we ignore end markers).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
-rw-r--r-- | drivers/virtio/virtio_ring.c | 44 | ||||
-rw-r--r-- | include/linux/virtio.h | 10 |
2 files changed, 54 insertions, 0 deletions
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index a78ad459cc85..5217baf5528c 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -366,6 +366,50 @@ int virtqueue_add_sgs(struct virtqueue *_vq, EXPORT_SYMBOL_GPL(virtqueue_add_sgs); /** + * virtqueue_add_outbuf - expose output buffers to other end + * @vq: the struct virtqueue we're talking about. + * @sgs: array of scatterlists (need not be terminated!) + * @num: the number of scatterlists readable by other side + * @data: the token identifying the buffer. + * @gfp: how to do memory allocations (if necessary). + * + * Caller must ensure we don't call this with other virtqueue operations + * at the same time (except where noted). + * + * Returns zero or a negative error (ie. ENOSPC, ENOMEM). + */ +int virtqueue_add_outbuf(struct virtqueue *vq, + struct scatterlist sg[], unsigned int num, + void *data, + gfp_t gfp) +{ + return virtqueue_add(vq, &sg, sg_next_arr, num, 0, 1, 0, data, gfp); +} +EXPORT_SYMBOL_GPL(virtqueue_add_outbuf); + +/** + * virtqueue_add_inbuf - expose input buffers to other end + * @vq: the struct virtqueue we're talking about. + * @sgs: array of scatterlists (need not be terminated!) + * @num: the number of scatterlists writable by other side + * @data: the token identifying the buffer. + * @gfp: how to do memory allocations (if necessary). + * + * Caller must ensure we don't call this with other virtqueue operations + * at the same time (except where noted). + * + * Returns zero or a negative error (ie. ENOSPC, ENOMEM). + */ +int virtqueue_add_inbuf(struct virtqueue *vq, + struct scatterlist sg[], unsigned int num, + void *data, + gfp_t gfp) +{ + return virtqueue_add(vq, &sg, sg_next_arr, 0, num, 0, 1, data, gfp); +} +EXPORT_SYMBOL_GPL(virtqueue_add_inbuf); + +/** * virtqueue_kick_prepare - first half of split virtqueue_kick call. * @vq: the struct virtqueue * diff --git a/include/linux/virtio.h b/include/linux/virtio.h index ac80288b2920..833f17b6a743 100644 --- a/include/linux/virtio.h +++ b/include/linux/virtio.h @@ -41,6 +41,16 @@ int virtqueue_add_buf(struct virtqueue *vq, void *data, gfp_t gfp); +int virtqueue_add_outbuf(struct virtqueue *vq, + struct scatterlist sg[], unsigned int num, + void *data, + gfp_t gfp); + +int virtqueue_add_inbuf(struct virtqueue *vq, + struct scatterlist sg[], unsigned int num, + void *data, + gfp_t gfp); + int virtqueue_add_sgs(struct virtqueue *vq, struct scatterlist *sgs[], unsigned int out_sgs, |