Re: [PATCH 04/10] vDPA: report virtio-block max segments in a request to user space

[Stefano Garzarella]

On Mon, Feb 19, 2024 at 02:56:00AM +0800, Zhu Lingshan wrote:

This commit allows vDPA reporting the maximum number of
segments in a request of virtio-block devices to
user space.

Signed-off-by: Zhu Lingshan <lingshan....@intel.com>
---
drivers/vdpa/vdpa.c       | 17 +++++++++++++++++
include/uapi/linux/vdpa.h |  1 +
2 files changed, 18 insertions(+)

Reviewed-by: Stefano Garzarella <sgarz...@redhat.com>

diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
index cc8f41d24c9c..8d00e9976aba 100644
--- a/drivers/vdpa/vdpa.c
+++ b/drivers/vdpa/vdpa.c
@@ -985,6 +985,20 @@ vdpa_dev_blk_block_size_config_fill(struct sk_buff *msg, 
u64 features,
        return nla_put_u32(msg, VDPA_ATTR_DEV_BLK_CFG_BLK_SIZE, val_u32);
}

+static int
+vdpa_dev_blk_seg_max_config_fill(struct sk_buff *msg, u64 features,
+                                const struct virtio_blk_config *config)
+{
+       u32 val_u32;
+
+       if ((features & BIT_ULL(VIRTIO_BLK_F_SEG_MAX)) == 0)
+               return 0;
+
+       val_u32 = __virtio32_to_cpu(true, config->seg_max);
+
+       return nla_put_u32(msg, VDPA_ATTR_DEV_BLK_CFG_SEG_MAX, val_u32);
+}
+
static int vdpa_dev_blk_config_fill(struct vdpa_device *vdev,
                                    struct sk_buff *msg)
{
@@ -1008,6 +1022,9 @@ static int vdpa_dev_blk_config_fill(struct vdpa_device 
*vdev,
        if (vdpa_dev_blk_block_size_config_fill(msg, features_device, &config))
                return -EMSGSIZE;

+       if (vdpa_dev_blk_seg_max_config_fill(msg, features_device, &config))
+               return -EMSGSIZE;
+
        return 0;
}

diff --git a/include/uapi/linux/vdpa.h b/include/uapi/linux/vdpa.h
index f3baf7ea7d6d..2dc92fca2052 100644
--- a/include/uapi/linux/vdpa.h
+++ b/include/uapi/linux/vdpa.h
@@ -59,6 +59,7 @@ enum vdpa_attr {
        VDPA_ATTR_DEV_BLK_CFG_CAPACITY,         /* u64 */
        VDPA_ATTR_DEV_BLK_CFG_SEG_SIZE,         /* u32 */
        VDPA_ATTR_DEV_BLK_CFG_BLK_SIZE,         /* u32 */
+       VDPA_ATTR_DEV_BLK_CFG_SEG_MAX,          /* u32 */

        /* new attributes must be added above here */
        VDPA_ATTR_MAX,
--
2.39.3