Re: [PATCH 02/10] vDPA: report virtio-block max segment size to user space

[Stefano Garzarella]

On Mon, Feb 19, 2024 at 02:55:58AM +0800, Zhu Lingshan wrote:

This commit allows reporting the max size of any
single segment 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(+)

diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
index d5ccb618de2b..ee1472d32b0d 100644
--- a/drivers/vdpa/vdpa.c
+++ b/drivers/vdpa/vdpa.c
@@ -956,6 +956,20 @@ vdpa_dev_blk_capacity_config_fill(struct sk_buff *msg,
                                 val_u64, VDPA_ATTR_PAD);
}

+static int
+vdpa_dev_blk_seg_size_config_fill(struct sk_buff *msg, u64 features,
+                                 const struct virtio_blk_config *config)
+{
+       u32 val_u32;
+
+       if ((features & BIT_ULL(VIRTIO_BLK_F_SIZE_MAX)) == 0)
+               return 0;
+
+       val_u32 = __virtio32_to_cpu(true, config->size_max);
+
+       return nla_put_u32(msg, VDPA_ATTR_DEV_BLK_CFG_SEG_SIZE, val_u32);

Should we call this VDPA_ATTR_DEV_BLK_CFG_SIZE_MAX ?

+}
+
static int vdpa_dev_blk_config_fill(struct vdpa_device *vdev,
                                    struct sk_buff *msg)
{
@@ -973,6 +987,9 @@ static int vdpa_dev_blk_config_fill(struct vdpa_device 
*vdev,
        if (vdpa_dev_blk_capacity_config_fill(msg, &config))
                return -EMSGSIZE;

+       if (vdpa_dev_blk_seg_size_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 1bf69226cb96..586bce3c906a 100644
--- a/include/uapi/linux/vdpa.h
+++ b/include/uapi/linux/vdpa.h
@@ -57,6 +57,7 @@ enum vdpa_attr {
        VDPA_ATTR_DEV_FEATURES,                 /* u64 */

        VDPA_ATTR_DEV_BLK_CFG_CAPACITY,         /* u64 */
+       VDPA_ATTR_DEV_BLK_CFG_SEG_SIZE,         /* u32 */

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