This is fairly simple: we create a request pointing at the 1k kmalloc, then just change the type so our do_req() knows to mark it as a GET_ID for the server.
Seems to work here; the only issue is that the error didn't get passed back from __blk_end_request_all to blk_execute_rq, so we set ->errors to 1 on error. Signed-off-by: Rusty Russell <[email protected]> Cc: Jens Axboe <[email protected]> --- drivers/block/virtio_blk.c | 66 +++++++++++++++++++++++++++++++++++---------- include/linux/virtio_blk.h | 4 ++ 2 files changed, 56 insertions(+), 14 deletions(-) diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -72,6 +72,8 @@ static void blk_done(struct virtqueue *v vbr->req->sense_len = vbr->in_hdr.sense_len; vbr->req->errors = vbr->in_hdr.errors; } + if (blk_special_request(vbr->req)) + vbr->req->errors = (error != 0); __blk_end_request_all(vbr->req, error); list_del(&vbr->list); @@ -105,6 +107,11 @@ static bool do_req(struct request_queue vbr->out_hdr.sector = 0; vbr->out_hdr.ioprio = req_get_ioprio(vbr->req); break; + case REQ_TYPE_SPECIAL: + vbr->out_hdr.type = VIRTIO_BLK_T_GET_ID; + vbr->out_hdr.sector = 0; + vbr->out_hdr.ioprio = req_get_ioprio(vbr->req); + break; case REQ_TYPE_LINUX_BLOCK: if (req->cmd[0] == REQ_LB_OP_FLUSH) { vbr->out_hdr.type = VIRTIO_BLK_T_FLUSH; @@ -201,29 +208,59 @@ struct virtio_blk_config_deprecated { __u8 identify[VIRTIO_BLK_ID_BYTES]; } __attribute__((packed)); -static int virtblk_identify(struct gendisk *disk, void *argp) +static int virtblk_identify_deprecated(struct virtio_blk *vblk, void *opaque) +{ + return virtio_config_buf(vblk->vdev, VIRTIO_BLK_F_IDENTIFY, + offsetof(struct virtio_blk_config_deprecated, identify), opaque, + VIRTIO_BLK_ID_BYTES); +} + +static int virtblk_get_id(struct virtio_blk *vblk, void *opaque) +{ + struct request *req; + struct bio *bio; + + bio = bio_map_kern(vblk->disk->queue, opaque, VIRTIO_BLK_ID_BYTES, + GFP_KERNEL); + if (IS_ERR(bio)) + return PTR_ERR(bio); + + req = blk_make_request(vblk->disk->queue, bio, GFP_KERNEL); + if (IS_ERR(req)) { + bio_put(bio); + return PTR_ERR(req); + } + + /* This is actually a special request. */ + req->cmd_type = REQ_TYPE_SPECIAL; + return blk_execute_rq(vblk->disk->queue, vblk->disk, req, false); +} + +static int virtblk_identify(struct gendisk *disk, void __user *argp) { struct virtio_blk *vblk = disk->private_data; void *opaque; - int err = -ENOMEM; + int err; opaque = kmalloc(VIRTIO_BLK_ID_BYTES, GFP_KERNEL); if (!opaque) - goto out; + return -ENOMEM; - err = virtio_config_buf(vblk->vdev, VIRTIO_BLK_F_IDENTIFY, - offsetof(struct virtio_blk_config_deprecated, identify), opaque, - VIRTIO_BLK_ID_BYTES); + /* The modern way. */ + if (virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_GET_ID)) + err = virtblk_get_id(vblk, opaque); + /* The deprecated way. */ + else if (virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_IDENTIFY)) + err = virtblk_identify_deprecated(vblk, opaque); + /* No way. */ + else + err = -ENOTTY; - if (err) - goto out_kfree; + if (!err) + if (copy_to_user(argp, opaque, VIRTIO_BLK_ID_BYTES)) + err = -EFAULT; - if (copy_to_user(argp, opaque, VIRTIO_BLK_ID_BYTES)) - err = -EFAULT; - -out_kfree: kfree(opaque); -out: return err; } @@ -460,7 +497,8 @@ static struct virtio_device_id id_table[ static unsigned int features[] = { VIRTIO_BLK_F_BARRIER, VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY, VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE, - VIRTIO_BLK_F_SCSI, VIRTIO_BLK_F_IDENTIFY, VIRTIO_BLK_F_FLUSH + VIRTIO_BLK_F_SCSI, VIRTIO_BLK_F_IDENTIFY, VIRTIO_BLK_F_FLUSH, + VIRTIO_BLK_F_GET_ID }; /* diff --git a/include/linux/virtio_blk.h b/include/linux/virtio_blk.h --- a/include/linux/virtio_blk.h +++ b/include/linux/virtio_blk.h @@ -15,6 +15,7 @@ #define VIRTIO_BLK_F_SCSI 7 /* Supports scsi command passthru */ #define VIRTIO_BLK_F_IDENTIFY 8 /* ATA IDENTIFY support (deprecated) */ #define VIRTIO_BLK_F_FLUSH 9 /* Cache flush command support */ +#define VIRTIO_BLK_F_GET_ID 10 /* VIRTIO_BLK_T_GET_ID support */ #define VIRTIO_BLK_ID_BYTES (sizeof(__u16[256])) /* IDENTIFY DATA */ @@ -65,6 +66,9 @@ struct virtio_blk_config { /* Cache flush command */ #define VIRTIO_BLK_T_FLUSH 4 +/* Get ID command */ +#define VIRTIO_BLK_T_GET_ID 8 + /* Barrier before this op. */ #define VIRTIO_BLK_T_BARRIER 0x80000000 _______________________________________________ Virtualization mailing list [email protected] https://lists.linux-foundation.org/mailman/listinfo/virtualization
