![Michael S. Tsirkin](/assets/img/avatar_default.png)
Switch virtio_blk to new virtqueue_xxx wrappers. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
523 lines
13 KiB
C
523 lines
13 KiB
C
//#define DEBUG
|
|
#include <linux/spinlock.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/blkdev.h>
|
|
#include <linux/hdreg.h>
|
|
#include <linux/virtio.h>
|
|
#include <linux/virtio_blk.h>
|
|
#include <linux/scatterlist.h>
|
|
|
|
#define PART_BITS 4
|
|
|
|
static int major, index;
|
|
|
|
struct virtio_blk
|
|
{
|
|
spinlock_t lock;
|
|
|
|
struct virtio_device *vdev;
|
|
struct virtqueue *vq;
|
|
|
|
/* The disk structure for the kernel. */
|
|
struct gendisk *disk;
|
|
|
|
/* Request tracking. */
|
|
struct list_head reqs;
|
|
|
|
mempool_t *pool;
|
|
|
|
/* What host tells us, plus 2 for header & tailer. */
|
|
unsigned int sg_elems;
|
|
|
|
/* Scatterlist: can be too big for stack. */
|
|
struct scatterlist sg[/*sg_elems*/];
|
|
};
|
|
|
|
struct virtblk_req
|
|
{
|
|
struct list_head list;
|
|
struct request *req;
|
|
struct virtio_blk_outhdr out_hdr;
|
|
struct virtio_scsi_inhdr in_hdr;
|
|
u8 status;
|
|
};
|
|
|
|
static void blk_done(struct virtqueue *vq)
|
|
{
|
|
struct virtio_blk *vblk = vq->vdev->priv;
|
|
struct virtblk_req *vbr;
|
|
unsigned int len;
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&vblk->lock, flags);
|
|
while ((vbr = virtqueue_get_buf(vblk->vq, &len)) != NULL) {
|
|
int error;
|
|
|
|
switch (vbr->status) {
|
|
case VIRTIO_BLK_S_OK:
|
|
error = 0;
|
|
break;
|
|
case VIRTIO_BLK_S_UNSUPP:
|
|
error = -ENOTTY;
|
|
break;
|
|
default:
|
|
error = -EIO;
|
|
break;
|
|
}
|
|
|
|
if (blk_pc_request(vbr->req)) {
|
|
vbr->req->resid_len = vbr->in_hdr.residual;
|
|
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);
|
|
mempool_free(vbr, vblk->pool);
|
|
}
|
|
/* In case queue is stopped waiting for more buffers. */
|
|
blk_start_queue(vblk->disk->queue);
|
|
spin_unlock_irqrestore(&vblk->lock, flags);
|
|
}
|
|
|
|
static bool do_req(struct request_queue *q, struct virtio_blk *vblk,
|
|
struct request *req)
|
|
{
|
|
unsigned long num, out = 0, in = 0;
|
|
struct virtblk_req *vbr;
|
|
|
|
vbr = mempool_alloc(vblk->pool, GFP_ATOMIC);
|
|
if (!vbr)
|
|
/* When another request finishes we'll try again. */
|
|
return false;
|
|
|
|
vbr->req = req;
|
|
switch (req->cmd_type) {
|
|
case REQ_TYPE_FS:
|
|
vbr->out_hdr.type = 0;
|
|
vbr->out_hdr.sector = blk_rq_pos(vbr->req);
|
|
vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
|
|
break;
|
|
case REQ_TYPE_BLOCK_PC:
|
|
vbr->out_hdr.type = VIRTIO_BLK_T_SCSI_CMD;
|
|
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;
|
|
vbr->out_hdr.sector = 0;
|
|
vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
|
|
break;
|
|
}
|
|
/*FALLTHRU*/
|
|
default:
|
|
/* We don't put anything else in the queue. */
|
|
BUG();
|
|
}
|
|
|
|
if (blk_barrier_rq(vbr->req))
|
|
vbr->out_hdr.type |= VIRTIO_BLK_T_BARRIER;
|
|
|
|
sg_set_buf(&vblk->sg[out++], &vbr->out_hdr, sizeof(vbr->out_hdr));
|
|
|
|
/*
|
|
* If this is a packet command we need a couple of additional headers.
|
|
* Behind the normal outhdr we put a segment with the scsi command
|
|
* block, and before the normal inhdr we put the sense data and the
|
|
* inhdr with additional status information before the normal inhdr.
|
|
*/
|
|
if (blk_pc_request(vbr->req))
|
|
sg_set_buf(&vblk->sg[out++], vbr->req->cmd, vbr->req->cmd_len);
|
|
|
|
num = blk_rq_map_sg(q, vbr->req, vblk->sg + out);
|
|
|
|
if (blk_pc_request(vbr->req)) {
|
|
sg_set_buf(&vblk->sg[num + out + in++], vbr->req->sense, 96);
|
|
sg_set_buf(&vblk->sg[num + out + in++], &vbr->in_hdr,
|
|
sizeof(vbr->in_hdr));
|
|
}
|
|
|
|
sg_set_buf(&vblk->sg[num + out + in++], &vbr->status,
|
|
sizeof(vbr->status));
|
|
|
|
if (num) {
|
|
if (rq_data_dir(vbr->req) == WRITE) {
|
|
vbr->out_hdr.type |= VIRTIO_BLK_T_OUT;
|
|
out += num;
|
|
} else {
|
|
vbr->out_hdr.type |= VIRTIO_BLK_T_IN;
|
|
in += num;
|
|
}
|
|
}
|
|
|
|
if (virtqueue_add_buf(vblk->vq, vblk->sg, out, in, vbr) < 0) {
|
|
mempool_free(vbr, vblk->pool);
|
|
return false;
|
|
}
|
|
|
|
list_add_tail(&vbr->list, &vblk->reqs);
|
|
return true;
|
|
}
|
|
|
|
static void do_virtblk_request(struct request_queue *q)
|
|
{
|
|
struct virtio_blk *vblk = q->queuedata;
|
|
struct request *req;
|
|
unsigned int issued = 0;
|
|
|
|
while ((req = blk_peek_request(q)) != NULL) {
|
|
BUG_ON(req->nr_phys_segments + 2 > vblk->sg_elems);
|
|
|
|
/* If this request fails, stop queue and wait for something to
|
|
finish to restart it. */
|
|
if (!do_req(q, vblk, req)) {
|
|
blk_stop_queue(q);
|
|
break;
|
|
}
|
|
blk_start_request(req);
|
|
issued++;
|
|
}
|
|
|
|
if (issued)
|
|
virtqueue_kick(vblk->vq);
|
|
}
|
|
|
|
static void virtblk_prepare_flush(struct request_queue *q, struct request *req)
|
|
{
|
|
req->cmd_type = REQ_TYPE_LINUX_BLOCK;
|
|
req->cmd[0] = REQ_LB_OP_FLUSH;
|
|
}
|
|
|
|
/* return id (s/n) string for *disk to *id_str
|
|
*/
|
|
static int virtblk_get_id(struct gendisk *disk, char *id_str)
|
|
{
|
|
struct virtio_blk *vblk = disk->private_data;
|
|
struct request *req;
|
|
struct bio *bio;
|
|
|
|
bio = bio_map_kern(vblk->disk->queue, id_str, 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);
|
|
}
|
|
|
|
req->cmd_type = REQ_TYPE_SPECIAL;
|
|
return blk_execute_rq(vblk->disk->queue, vblk->disk, req, false);
|
|
}
|
|
|
|
static int virtblk_ioctl(struct block_device *bdev, fmode_t mode,
|
|
unsigned cmd, unsigned long data)
|
|
{
|
|
struct gendisk *disk = bdev->bd_disk;
|
|
struct virtio_blk *vblk = disk->private_data;
|
|
|
|
if (cmd == 0x56424944) { /* 'VBID' */
|
|
void __user *usr_data = (void __user *)data;
|
|
char id_str[VIRTIO_BLK_ID_BYTES];
|
|
int err;
|
|
|
|
err = virtblk_get_id(disk, id_str);
|
|
if (!err && copy_to_user(usr_data, id_str, VIRTIO_BLK_ID_BYTES))
|
|
err = -EFAULT;
|
|
return err;
|
|
}
|
|
/*
|
|
* Only allow the generic SCSI ioctls if the host can support it.
|
|
*/
|
|
if (!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_SCSI))
|
|
return -ENOTTY;
|
|
|
|
return scsi_cmd_ioctl(disk->queue, disk, mode, cmd,
|
|
(void __user *)data);
|
|
}
|
|
|
|
/* We provide getgeo only to please some old bootloader/partitioning tools */
|
|
static int virtblk_getgeo(struct block_device *bd, struct hd_geometry *geo)
|
|
{
|
|
struct virtio_blk *vblk = bd->bd_disk->private_data;
|
|
struct virtio_blk_geometry vgeo;
|
|
int err;
|
|
|
|
/* see if the host passed in geometry config */
|
|
err = virtio_config_val(vblk->vdev, VIRTIO_BLK_F_GEOMETRY,
|
|
offsetof(struct virtio_blk_config, geometry),
|
|
&vgeo);
|
|
|
|
if (!err) {
|
|
geo->heads = vgeo.heads;
|
|
geo->sectors = vgeo.sectors;
|
|
geo->cylinders = vgeo.cylinders;
|
|
} else {
|
|
/* some standard values, similar to sd */
|
|
geo->heads = 1 << 6;
|
|
geo->sectors = 1 << 5;
|
|
geo->cylinders = get_capacity(bd->bd_disk) >> 11;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static const struct block_device_operations virtblk_fops = {
|
|
.locked_ioctl = virtblk_ioctl,
|
|
.owner = THIS_MODULE,
|
|
.getgeo = virtblk_getgeo,
|
|
};
|
|
|
|
static int index_to_minor(int index)
|
|
{
|
|
return index << PART_BITS;
|
|
}
|
|
|
|
static int __devinit virtblk_probe(struct virtio_device *vdev)
|
|
{
|
|
struct virtio_blk *vblk;
|
|
struct request_queue *q;
|
|
int err;
|
|
u64 cap;
|
|
u32 v, blk_size, sg_elems, opt_io_size;
|
|
u16 min_io_size;
|
|
u8 physical_block_exp, alignment_offset;
|
|
|
|
if (index_to_minor(index) >= 1 << MINORBITS)
|
|
return -ENOSPC;
|
|
|
|
/* We need to know how many segments before we allocate. */
|
|
err = virtio_config_val(vdev, VIRTIO_BLK_F_SEG_MAX,
|
|
offsetof(struct virtio_blk_config, seg_max),
|
|
&sg_elems);
|
|
if (err)
|
|
sg_elems = 1;
|
|
|
|
/* We need an extra sg elements at head and tail. */
|
|
sg_elems += 2;
|
|
vdev->priv = vblk = kmalloc(sizeof(*vblk) +
|
|
sizeof(vblk->sg[0]) * sg_elems, GFP_KERNEL);
|
|
if (!vblk) {
|
|
err = -ENOMEM;
|
|
goto out;
|
|
}
|
|
|
|
INIT_LIST_HEAD(&vblk->reqs);
|
|
spin_lock_init(&vblk->lock);
|
|
vblk->vdev = vdev;
|
|
vblk->sg_elems = sg_elems;
|
|
sg_init_table(vblk->sg, vblk->sg_elems);
|
|
|
|
/* We expect one virtqueue, for output. */
|
|
vblk->vq = virtio_find_single_vq(vdev, blk_done, "requests");
|
|
if (IS_ERR(vblk->vq)) {
|
|
err = PTR_ERR(vblk->vq);
|
|
goto out_free_vblk;
|
|
}
|
|
|
|
vblk->pool = mempool_create_kmalloc_pool(1,sizeof(struct virtblk_req));
|
|
if (!vblk->pool) {
|
|
err = -ENOMEM;
|
|
goto out_free_vq;
|
|
}
|
|
|
|
/* FIXME: How many partitions? How long is a piece of string? */
|
|
vblk->disk = alloc_disk(1 << PART_BITS);
|
|
if (!vblk->disk) {
|
|
err = -ENOMEM;
|
|
goto out_mempool;
|
|
}
|
|
|
|
q = vblk->disk->queue = blk_init_queue(do_virtblk_request, &vblk->lock);
|
|
if (!q) {
|
|
err = -ENOMEM;
|
|
goto out_put_disk;
|
|
}
|
|
|
|
q->queuedata = vblk;
|
|
|
|
if (index < 26) {
|
|
sprintf(vblk->disk->disk_name, "vd%c", 'a' + index % 26);
|
|
} else if (index < (26 + 1) * 26) {
|
|
sprintf(vblk->disk->disk_name, "vd%c%c",
|
|
'a' + index / 26 - 1, 'a' + index % 26);
|
|
} else {
|
|
const unsigned int m1 = (index / 26 - 1) / 26 - 1;
|
|
const unsigned int m2 = (index / 26 - 1) % 26;
|
|
const unsigned int m3 = index % 26;
|
|
sprintf(vblk->disk->disk_name, "vd%c%c%c",
|
|
'a' + m1, 'a' + m2, 'a' + m3);
|
|
}
|
|
|
|
vblk->disk->major = major;
|
|
vblk->disk->first_minor = index_to_minor(index);
|
|
vblk->disk->private_data = vblk;
|
|
vblk->disk->fops = &virtblk_fops;
|
|
vblk->disk->driverfs_dev = &vdev->dev;
|
|
index++;
|
|
|
|
/* If barriers are supported, tell block layer that queue is ordered */
|
|
if (virtio_has_feature(vdev, VIRTIO_BLK_F_FLUSH))
|
|
blk_queue_ordered(q, QUEUE_ORDERED_DRAIN_FLUSH,
|
|
virtblk_prepare_flush);
|
|
else if (virtio_has_feature(vdev, VIRTIO_BLK_F_BARRIER))
|
|
blk_queue_ordered(q, QUEUE_ORDERED_TAG, NULL);
|
|
|
|
/* If disk is read-only in the host, the guest should obey */
|
|
if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO))
|
|
set_disk_ro(vblk->disk, 1);
|
|
|
|
/* Host must always specify the capacity. */
|
|
vdev->config->get(vdev, offsetof(struct virtio_blk_config, capacity),
|
|
&cap, sizeof(cap));
|
|
|
|
/* If capacity is too big, truncate with warning. */
|
|
if ((sector_t)cap != cap) {
|
|
dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n",
|
|
(unsigned long long)cap);
|
|
cap = (sector_t)-1;
|
|
}
|
|
set_capacity(vblk->disk, cap);
|
|
|
|
/* We can handle whatever the host told us to handle. */
|
|
blk_queue_max_segments(q, vblk->sg_elems-2);
|
|
|
|
/* No need to bounce any requests */
|
|
blk_queue_bounce_limit(q, BLK_BOUNCE_ANY);
|
|
|
|
/* No real sector limit. */
|
|
blk_queue_max_hw_sectors(q, -1U);
|
|
|
|
/* Host can optionally specify maximum segment size and number of
|
|
* segments. */
|
|
err = virtio_config_val(vdev, VIRTIO_BLK_F_SIZE_MAX,
|
|
offsetof(struct virtio_blk_config, size_max),
|
|
&v);
|
|
if (!err)
|
|
blk_queue_max_segment_size(q, v);
|
|
else
|
|
blk_queue_max_segment_size(q, -1U);
|
|
|
|
/* Host can optionally specify the block size of the device */
|
|
err = virtio_config_val(vdev, VIRTIO_BLK_F_BLK_SIZE,
|
|
offsetof(struct virtio_blk_config, blk_size),
|
|
&blk_size);
|
|
if (!err)
|
|
blk_queue_logical_block_size(q, blk_size);
|
|
else
|
|
blk_size = queue_logical_block_size(q);
|
|
|
|
/* Use topology information if available */
|
|
err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY,
|
|
offsetof(struct virtio_blk_config, physical_block_exp),
|
|
&physical_block_exp);
|
|
if (!err && physical_block_exp)
|
|
blk_queue_physical_block_size(q,
|
|
blk_size * (1 << physical_block_exp));
|
|
|
|
err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY,
|
|
offsetof(struct virtio_blk_config, alignment_offset),
|
|
&alignment_offset);
|
|
if (!err && alignment_offset)
|
|
blk_queue_alignment_offset(q, blk_size * alignment_offset);
|
|
|
|
err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY,
|
|
offsetof(struct virtio_blk_config, min_io_size),
|
|
&min_io_size);
|
|
if (!err && min_io_size)
|
|
blk_queue_io_min(q, blk_size * min_io_size);
|
|
|
|
err = virtio_config_val(vdev, VIRTIO_BLK_F_TOPOLOGY,
|
|
offsetof(struct virtio_blk_config, opt_io_size),
|
|
&opt_io_size);
|
|
if (!err && opt_io_size)
|
|
blk_queue_io_opt(q, blk_size * opt_io_size);
|
|
|
|
|
|
add_disk(vblk->disk);
|
|
return 0;
|
|
|
|
out_put_disk:
|
|
put_disk(vblk->disk);
|
|
out_mempool:
|
|
mempool_destroy(vblk->pool);
|
|
out_free_vq:
|
|
vdev->config->del_vqs(vdev);
|
|
out_free_vblk:
|
|
kfree(vblk);
|
|
out:
|
|
return err;
|
|
}
|
|
|
|
static void __devexit virtblk_remove(struct virtio_device *vdev)
|
|
{
|
|
struct virtio_blk *vblk = vdev->priv;
|
|
|
|
/* Nothing should be pending. */
|
|
BUG_ON(!list_empty(&vblk->reqs));
|
|
|
|
/* Stop all the virtqueues. */
|
|
vdev->config->reset(vdev);
|
|
|
|
del_gendisk(vblk->disk);
|
|
blk_cleanup_queue(vblk->disk->queue);
|
|
put_disk(vblk->disk);
|
|
mempool_destroy(vblk->pool);
|
|
vdev->config->del_vqs(vdev);
|
|
kfree(vblk);
|
|
}
|
|
|
|
static const struct virtio_device_id id_table[] = {
|
|
{ VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID },
|
|
{ 0 },
|
|
};
|
|
|
|
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_FLUSH, VIRTIO_BLK_F_TOPOLOGY
|
|
};
|
|
|
|
/*
|
|
* virtio_blk causes spurious section mismatch warning by
|
|
* simultaneously referring to a __devinit and a __devexit function.
|
|
* Use __refdata to avoid this warning.
|
|
*/
|
|
static struct virtio_driver __refdata virtio_blk = {
|
|
.feature_table = features,
|
|
.feature_table_size = ARRAY_SIZE(features),
|
|
.driver.name = KBUILD_MODNAME,
|
|
.driver.owner = THIS_MODULE,
|
|
.id_table = id_table,
|
|
.probe = virtblk_probe,
|
|
.remove = __devexit_p(virtblk_remove),
|
|
};
|
|
|
|
static int __init init(void)
|
|
{
|
|
major = register_blkdev(0, "virtblk");
|
|
if (major < 0)
|
|
return major;
|
|
return register_virtio_driver(&virtio_blk);
|
|
}
|
|
|
|
static void __exit fini(void)
|
|
{
|
|
unregister_blkdev(major, "virtblk");
|
|
unregister_virtio_driver(&virtio_blk);
|
|
}
|
|
module_init(init);
|
|
module_exit(fini);
|
|
|
|
MODULE_DEVICE_TABLE(virtio, id_table);
|
|
MODULE_DESCRIPTION("Virtio block driver");
|
|
MODULE_LICENSE("GPL");
|