--- /dev/null
+//#define DEBUG
+#include <linux/spinlock.h>
+#include <linux/slab.h>
+#include <linux/blkdev.h>
+#include <linux/hdreg.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/virtio.h>
+#include <linux/virtio_blk.h>
+#include <linux/scatterlist.h>
+#include <linux/string_helpers.h>
+#include <scsi/scsi_cmnd.h>
+#include <linux/idr.h>
+#include <linux/blk-mq.h>
+#include <linux/numa.h>
+
+#define PART_BITS 4
+#define VQ_NAME_LEN 16
+
+static int major;
+static DEFINE_IDA(vd_index_ida);
+
+static struct workqueue_struct *virtblk_wq;
+
+struct virtio_blk_vq {
+ struct virtqueue *vq;
+ spinlock_t lock;
+ char name[VQ_NAME_LEN];
+} ____cacheline_aligned_in_smp;
+
+struct virtio_blk {
+ struct virtio_device *vdev;
+
+ /* The disk structure for the kernel. */
+ struct gendisk *disk;
+
+ /* Block layer tags. */
+ struct blk_mq_tag_set tag_set;
+
+ /* Process context for config space updates */
+ struct work_struct config_work;
+
+ /* What host tells us, plus 2 for header & tailer. */
+ unsigned int sg_elems;
+
+ /* Ida index - used to track minor number allocations. */
+ int index;
+
+ /* num of vqs */
+ int num_vqs;
+ struct virtio_blk_vq *vqs;
+};
+
+struct virtblk_req {
+ struct request *req;
+ struct virtio_blk_outhdr out_hdr;
+ struct virtio_scsi_inhdr in_hdr;
+ u8 status;
+ struct scatterlist sg[];
+};
+
+static inline int virtblk_result(struct virtblk_req *vbr)
+{
+ switch (vbr->status) {
+ case VIRTIO_BLK_S_OK:
+ return 0;
+ case VIRTIO_BLK_S_UNSUPP:
+ return -ENOTTY;
+ default:
+ return -EIO;
+ }
+}
+
+static int __virtblk_add_req(struct virtqueue *vq,
+ struct virtblk_req *vbr,
+ struct scatterlist *data_sg,
+ bool have_data)
+{
+ struct scatterlist hdr, status, cmd, sense, inhdr, *sgs[6];
+ unsigned int num_out = 0, num_in = 0;
+ __virtio32 type = vbr->out_hdr.type & ~cpu_to_virtio32(vq->vdev, VIRTIO_BLK_T_OUT);
+
+ sg_init_one(&hdr, &vbr->out_hdr, sizeof(vbr->out_hdr));
+ sgs[num_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.
+ */
+ if (type == cpu_to_virtio32(vq->vdev, VIRTIO_BLK_T_SCSI_CMD)) {
+ sg_init_one(&cmd, vbr->req->cmd, vbr->req->cmd_len);
+ sgs[num_out++] = &cmd;
+ }
+
+ if (have_data) {
+ if (vbr->out_hdr.type & cpu_to_virtio32(vq->vdev, VIRTIO_BLK_T_OUT))
+ sgs[num_out++] = data_sg;
+ else
+ sgs[num_out + num_in++] = data_sg;
+ }
+
+ if (type == cpu_to_virtio32(vq->vdev, VIRTIO_BLK_T_SCSI_CMD)) {
+ sg_init_one(&sense, vbr->req->sense, SCSI_SENSE_BUFFERSIZE);
+ sgs[num_out + num_in++] = &sense;
+ sg_init_one(&inhdr, &vbr->in_hdr, sizeof(vbr->in_hdr));
+ sgs[num_out + num_in++] = &inhdr;
+ }
+
+ sg_init_one(&status, &vbr->status, sizeof(vbr->status));
+ sgs[num_out + num_in++] = &status;
+
+ return virtqueue_add_sgs(vq, sgs, num_out, num_in, vbr, GFP_ATOMIC);
+}
+
+static inline void virtblk_request_done(struct request *req)
+{
+ struct virtblk_req *vbr = blk_mq_rq_to_pdu(req);
+ struct virtio_blk *vblk = req->q->queuedata;
+ int error = virtblk_result(vbr);
+
+ if (req->cmd_type == REQ_TYPE_BLOCK_PC) {
+ req->resid_len = virtio32_to_cpu(vblk->vdev, vbr->in_hdr.residual);
+ req->sense_len = virtio32_to_cpu(vblk->vdev, vbr->in_hdr.sense_len);
+ req->errors = virtio32_to_cpu(vblk->vdev, vbr->in_hdr.errors);
+ } else if (req->cmd_type == REQ_TYPE_SPECIAL) {
+ req->errors = (error != 0);
+ }
+
+ blk_mq_end_request(req, error);
+}
+
+static void virtblk_done(struct virtqueue *vq)
+{
+ struct virtio_blk *vblk = vq->vdev->priv;
+ bool req_done = false;
+ int qid = vq->index;
+ struct virtblk_req *vbr;
+ unsigned long flags;
+ unsigned int len;
+
+ spin_lock_irqsave(&vblk->vqs[qid].lock, flags);
+ do {
+ virtqueue_disable_cb(vq);
+ while ((vbr = virtqueue_get_buf(vblk->vqs[qid].vq, &len)) != NULL) {
+ blk_mq_complete_request(vbr->req);
+ req_done = true;
+ }
+ if (unlikely(virtqueue_is_broken(vq)))
+ break;
+ } while (!virtqueue_enable_cb(vq));
+
+ /* In case queue is stopped waiting for more buffers. */
+ if (req_done)
+ blk_mq_start_stopped_hw_queues(vblk->disk->queue, true);
+ spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags);
+}
+
+static int virtio_queue_rq(struct blk_mq_hw_ctx *hctx,
+ const struct blk_mq_queue_data *bd)
+{
+ struct virtio_blk *vblk = hctx->queue->queuedata;
+ struct request *req = bd->rq;
+ struct virtblk_req *vbr = blk_mq_rq_to_pdu(req);
+ unsigned long flags;
+ unsigned int num;
+ int qid = hctx->queue_num;
+ int err;
+ bool notify = false;
+
+ BUG_ON(req->nr_phys_segments + 2 > vblk->sg_elems);
+
+ vbr->req = req;
+ if (req->cmd_flags & REQ_FLUSH) {
+ vbr->out_hdr.type = cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_FLUSH);
+ vbr->out_hdr.sector = 0;
+ vbr->out_hdr.ioprio = cpu_to_virtio32(vblk->vdev, req_get_ioprio(vbr->req));
+ } else {
+ switch (req->cmd_type) {
+ case REQ_TYPE_FS:
+ vbr->out_hdr.type = 0;
+ vbr->out_hdr.sector = cpu_to_virtio64(vblk->vdev, blk_rq_pos(vbr->req));
+ vbr->out_hdr.ioprio = cpu_to_virtio32(vblk->vdev, req_get_ioprio(vbr->req));
+ break;
+ case REQ_TYPE_BLOCK_PC:
+ vbr->out_hdr.type = cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_SCSI_CMD);
+ vbr->out_hdr.sector = 0;
+ vbr->out_hdr.ioprio = cpu_to_virtio32(vblk->vdev, req_get_ioprio(vbr->req));
+ break;
+ case REQ_TYPE_SPECIAL:
+ vbr->out_hdr.type = cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_GET_ID);
+ vbr->out_hdr.sector = 0;
+ vbr->out_hdr.ioprio = cpu_to_virtio32(vblk->vdev, req_get_ioprio(vbr->req));
+ break;
+ default:
+ /* We don't put anything else in the queue. */
+ BUG();
+ }
+ }
+
+ blk_mq_start_request(req);
+
+ num = blk_rq_map_sg(hctx->queue, vbr->req, vbr->sg);
+ if (num) {
+ if (rq_data_dir(vbr->req) == WRITE)
+ vbr->out_hdr.type |= cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_OUT);
+ else
+ vbr->out_hdr.type |= cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_IN);
+ }
+
+ spin_lock_irqsave(&vblk->vqs[qid].lock, flags);
+ err = __virtblk_add_req(vblk->vqs[qid].vq, vbr, vbr->sg, num);
+ if (err) {
+ virtqueue_kick(vblk->vqs[qid].vq);
+ blk_mq_stop_hw_queue(hctx);
+ spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags);
+ /* Out of mem doesn't actually happen, since we fall back
+ * to direct descriptors */
+ if (err == -ENOMEM || err == -ENOSPC)
+ return BLK_MQ_RQ_QUEUE_BUSY;
+ return BLK_MQ_RQ_QUEUE_ERROR;
+ }
+
+ if (bd->last && virtqueue_kick_prepare(vblk->vqs[qid].vq))
+ notify = true;
+ spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags);
+
+ if (notify)
+ virtqueue_notify(vblk->vqs[qid].vq);
+ return BLK_MQ_RQ_QUEUE_OK;
+}
+
+/* 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;
+ int err;
+
+ 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;
+ err = blk_execute_rq(vblk->disk->queue, vblk->disk, req, false);
+ blk_put_request(req);
+
+ return err;
+}
+
+static int virtblk_ioctl(struct block_device *bdev, fmode_t mode,
+ unsigned int cmd, unsigned long data)
+{
+ struct gendisk *disk = bdev->bd_disk;
+ struct virtio_blk *vblk = disk->private_data;
+
+ /*
+ * 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_blk_ioctl(bdev, 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;
+
+ /* see if the host passed in geometry config */
+ if (virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_GEOMETRY)) {
+ virtio_cread(vblk->vdev, struct virtio_blk_config,
+ geometry.cylinders, &geo->cylinders);
+ virtio_cread(vblk->vdev, struct virtio_blk_config,
+ geometry.heads, &geo->heads);
+ virtio_cread(vblk->vdev, struct virtio_blk_config,
+ geometry.sectors, &geo->sectors);
+ } 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 = {
+ .ioctl = virtblk_ioctl,
+ .owner = THIS_MODULE,
+ .getgeo = virtblk_getgeo,
+};
+
+static int index_to_minor(int index)
+{
+ return index << PART_BITS;
+}
+
+static int minor_to_index(int minor)
+{
+ return minor >> PART_BITS;
+}
+
+static ssize_t virtblk_serial_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct gendisk *disk = dev_to_disk(dev);
+ int err;
+
+ /* sysfs gives us a PAGE_SIZE buffer */
+ BUILD_BUG_ON(PAGE_SIZE < VIRTIO_BLK_ID_BYTES);
+
+ buf[VIRTIO_BLK_ID_BYTES] = '\0';
+ err = virtblk_get_id(disk, buf);
+ if (!err)
+ return strlen(buf);
+
+ if (err == -EIO) /* Unsupported? Make it empty. */
+ return 0;
+
+ return err;
+}
+
+static DEVICE_ATTR(serial, S_IRUGO, virtblk_serial_show, NULL);
+
+static void virtblk_config_changed_work(struct work_struct *work)
+{
+ struct virtio_blk *vblk =
+ container_of(work, struct virtio_blk, config_work);
+ struct virtio_device *vdev = vblk->vdev;
+ struct request_queue *q = vblk->disk->queue;
+ char cap_str_2[10], cap_str_10[10];
+ char *envp[] = { "RESIZE=1", NULL };
+ u64 capacity;
+
+ /* Host must always specify the capacity. */
+ virtio_cread(vdev, struct virtio_blk_config, capacity, &capacity);
+
+ /* If capacity is too big, truncate with warning. */
+ if ((sector_t)capacity != capacity) {
+ dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n",
+ (unsigned long long)capacity);
+ capacity = (sector_t)-1;
+ }
+
+ string_get_size(capacity, queue_logical_block_size(q),
+ STRING_UNITS_2, cap_str_2, sizeof(cap_str_2));
+ string_get_size(capacity, queue_logical_block_size(q),
+ STRING_UNITS_10, cap_str_10, sizeof(cap_str_10));
+
+ dev_notice(&vdev->dev,
+ "new size: %llu %d-byte logical blocks (%s/%s)\n",
+ (unsigned long long)capacity,
+ queue_logical_block_size(q),
+ cap_str_10, cap_str_2);
+
+ set_capacity(vblk->disk, capacity);
+ revalidate_disk(vblk->disk);
+ kobject_uevent_env(&disk_to_dev(vblk->disk)->kobj, KOBJ_CHANGE, envp);
+}
+
+static void virtblk_config_changed(struct virtio_device *vdev)
+{
+ struct virtio_blk *vblk = vdev->priv;
+
+ queue_work(virtblk_wq, &vblk->config_work);
+}
+
+static int init_vq(struct virtio_blk *vblk)
+{
+ int err = 0;
+ int i;
+ vq_callback_t **callbacks;
+ const char **names;
+ struct virtqueue **vqs;
+ unsigned short num_vqs;
+ struct virtio_device *vdev = vblk->vdev;
+
+ err = virtio_cread_feature(vdev, VIRTIO_BLK_F_MQ,
+ struct virtio_blk_config, num_queues,
+ &num_vqs);
+ if (err)
+ num_vqs = 1;
+
+ vblk->vqs = kmalloc(sizeof(*vblk->vqs) * num_vqs, GFP_KERNEL);
+ if (!vblk->vqs) {
+ err = -ENOMEM;
+ goto out;
+ }
+
+ names = kmalloc(sizeof(*names) * num_vqs, GFP_KERNEL);
+ if (!names)
+ goto err_names;
+
+ callbacks = kmalloc(sizeof(*callbacks) * num_vqs, GFP_KERNEL);
+ if (!callbacks)
+ goto err_callbacks;
+
+ vqs = kmalloc(sizeof(*vqs) * num_vqs, GFP_KERNEL);
+ if (!vqs)
+ goto err_vqs;
+
+ for (i = 0; i < num_vqs; i++) {
+ callbacks[i] = virtblk_done;
+ snprintf(vblk->vqs[i].name, VQ_NAME_LEN, "req.%d", i);
+ names[i] = vblk->vqs[i].name;
+ }
+
+ /* Discover virtqueues and write information to configuration. */
+ err = vdev->config->find_vqs(vdev, num_vqs, vqs, callbacks, names);
+ if (err)
+ goto err_find_vqs;
+
+ for (i = 0; i < num_vqs; i++) {
+ spin_lock_init(&vblk->vqs[i].lock);
+ vblk->vqs[i].vq = vqs[i];
+ }
+ vblk->num_vqs = num_vqs;
+
+ err_find_vqs:
+ kfree(vqs);
+ err_vqs:
+ kfree(callbacks);
+ err_callbacks:
+ kfree(names);
+ err_names:
+ if (err)
+ kfree(vblk->vqs);
+ out:
+ return err;
+}
+
+/*
+ * Legacy naming scheme used for virtio devices. We are stuck with it for
+ * virtio blk but don't ever use it for any new driver.
+ */
+static int virtblk_name_format(char *prefix, int index, char *buf, int buflen)
+{
+ const int base = 'z' - 'a' + 1;
+ char *begin = buf + strlen(prefix);
+ char *end = buf + buflen;
+ char *p;
+ int unit;
+
+ p = end - 1;
+ *p = '\0';
+ unit = base;
+ do {
+ if (p == begin)
+ return -EINVAL;
+ *--p = 'a' + (index % unit);
+ index = (index / unit) - 1;
+ } while (index >= 0);
+
+ memmove(begin, p, end - p);
+ memcpy(buf, prefix, strlen(prefix));
+
+ return 0;
+}
+
+static int virtblk_get_cache_mode(struct virtio_device *vdev)
+{
+ u8 writeback;
+ int err;
+
+ err = virtio_cread_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE,
+ struct virtio_blk_config, wce,
+ &writeback);
+ if (err)
+ writeback = virtio_has_feature(vdev, VIRTIO_BLK_F_WCE) ||
+ virtio_has_feature(vdev, VIRTIO_F_VERSION_1);
+
+ return writeback;
+}
+
+static void virtblk_update_cache_mode(struct virtio_device *vdev)
+{
+ u8 writeback = virtblk_get_cache_mode(vdev);
+ struct virtio_blk *vblk = vdev->priv;
+
+ if (writeback)
+ blk_queue_flush(vblk->disk->queue, REQ_FLUSH);
+ else
+ blk_queue_flush(vblk->disk->queue, 0);
+
+ revalidate_disk(vblk->disk);
+}
+
+static const char *const virtblk_cache_types[] = {
+ "write through", "write back"
+};
+
+static ssize_t
+virtblk_cache_type_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct gendisk *disk = dev_to_disk(dev);
+ struct virtio_blk *vblk = disk->private_data;
+ struct virtio_device *vdev = vblk->vdev;
+ int i;
+
+ BUG_ON(!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_CONFIG_WCE));
+ for (i = ARRAY_SIZE(virtblk_cache_types); --i >= 0; )
+ if (sysfs_streq(buf, virtblk_cache_types[i]))
+ break;
+
+ if (i < 0)
+ return -EINVAL;
+
+ virtio_cwrite8(vdev, offsetof(struct virtio_blk_config, wce), i);
+ virtblk_update_cache_mode(vdev);
+ return count;
+}
+
+static ssize_t
+virtblk_cache_type_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct gendisk *disk = dev_to_disk(dev);
+ struct virtio_blk *vblk = disk->private_data;
+ u8 writeback = virtblk_get_cache_mode(vblk->vdev);
+
+ BUG_ON(writeback >= ARRAY_SIZE(virtblk_cache_types));
+ return snprintf(buf, 40, "%s\n", virtblk_cache_types[writeback]);
+}
+
+static const struct device_attribute dev_attr_cache_type_ro =
+ __ATTR(cache_type, S_IRUGO,
+ virtblk_cache_type_show, NULL);
+static const struct device_attribute dev_attr_cache_type_rw =
+ __ATTR(cache_type, S_IRUGO|S_IWUSR,
+ virtblk_cache_type_show, virtblk_cache_type_store);
+
+static int virtblk_init_request(void *data, struct request *rq,
+ unsigned int hctx_idx, unsigned int request_idx,
+ unsigned int numa_node)
+{
+ struct virtio_blk *vblk = data;
+ struct virtblk_req *vbr = blk_mq_rq_to_pdu(rq);
+
+ sg_init_table(vbr->sg, vblk->sg_elems);
+ return 0;
+}
+
+static struct blk_mq_ops virtio_mq_ops = {
+ .queue_rq = virtio_queue_rq,
+ .map_queue = blk_mq_map_queue,
+ .complete = virtblk_request_done,
+ .init_request = virtblk_init_request,
+};
+
+static unsigned int virtblk_queue_depth;
+module_param_named(queue_depth, virtblk_queue_depth, uint, 0444);
+
+static int virtblk_probe(struct virtio_device *vdev)
+{
+ struct virtio_blk *vblk;
+ struct request_queue *q;
+ int err, index;
+
+ u64 cap;
+ u32 v, blk_size, sg_elems, opt_io_size;
+ u16 min_io_size;
+ u8 physical_block_exp, alignment_offset;
+
+ if (!vdev->config->get) {
+ dev_err(&vdev->dev, "%s failure: config access disabled\n",
+ __func__);
+ return -EINVAL;
+ }
+
+ err = ida_simple_get(&vd_index_ida, 0, minor_to_index(1 << MINORBITS),
+ GFP_KERNEL);
+ if (err < 0)
+ goto out;
+ index = err;
+
+ /* We need to know how many segments before we allocate. */
+ err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SEG_MAX,
+ struct virtio_blk_config, seg_max,
+ &sg_elems);
+
+ /* We need at least one SG element, whatever they say. */
+ if (err || !sg_elems)
+ sg_elems = 1;
+
+ /* We need an extra sg elements at head and tail. */
+ sg_elems += 2;
+ vdev->priv = vblk = kmalloc(sizeof(*vblk), GFP_KERNEL);
+ if (!vblk) {
+ err = -ENOMEM;
+ goto out_free_index;
+ }
+
+ vblk->vdev = vdev;
+ vblk->sg_elems = sg_elems;
+
+ INIT_WORK(&vblk->config_work, virtblk_config_changed_work);
+
+ err = init_vq(vblk);
+ if (err)
+ goto out_free_vblk;
+
+ /* 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_free_vq;
+ }
+
+ /* Default queue sizing is to fill the ring. */
+ if (!virtblk_queue_depth) {
+ virtblk_queue_depth = vblk->vqs[0].vq->num_free;
+ /* ... but without indirect descs, we use 2 descs per req */
+ if (!virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC))
+ virtblk_queue_depth /= 2;
+ }
+
+ memset(&vblk->tag_set, 0, sizeof(vblk->tag_set));
+ vblk->tag_set.ops = &virtio_mq_ops;
+ vblk->tag_set.queue_depth = virtblk_queue_depth;
+ vblk->tag_set.numa_node = NUMA_NO_NODE;
+ vblk->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
+ vblk->tag_set.cmd_size =
+ sizeof(struct virtblk_req) +
+ sizeof(struct scatterlist) * sg_elems;
+ vblk->tag_set.driver_data = vblk;
+ vblk->tag_set.nr_hw_queues = vblk->num_vqs;
+
+ err = blk_mq_alloc_tag_set(&vblk->tag_set);
+ if (err)
+ goto out_put_disk;
+
+ q = vblk->disk->queue = blk_mq_init_queue(&vblk->tag_set);
+ if (IS_ERR(q)) {
+ err = -ENOMEM;
+ goto out_free_tags;
+ }
+
+ q->queuedata = vblk;
+
+ virtblk_name_format("vd", index, vblk->disk->disk_name, DISK_NAME_LEN);
+
+ 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;
+ vblk->index = index;
+
+ /* configure queue flush support */
+ virtblk_update_cache_mode(vdev);
+
+ /* 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. */
+ virtio_cread(vdev, struct virtio_blk_config, capacity, &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_cread_feature(vdev, VIRTIO_BLK_F_SIZE_MAX,
+ 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_cread_feature(vdev, VIRTIO_BLK_F_BLK_SIZE,
+ 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_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
+ 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_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
+ struct virtio_blk_config, alignment_offset,
+ &alignment_offset);
+ if (!err && alignment_offset)
+ blk_queue_alignment_offset(q, blk_size * alignment_offset);
+
+ err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
+ 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_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
+ 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);
+
+ virtio_device_ready(vdev);
+
+ add_disk(vblk->disk);
+ err = device_create_file(disk_to_dev(vblk->disk), &dev_attr_serial);
+ if (err)
+ goto out_del_disk;
+
+ if (virtio_has_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE))
+ err = device_create_file(disk_to_dev(vblk->disk),
+ &dev_attr_cache_type_rw);
+ else
+ err = device_create_file(disk_to_dev(vblk->disk),
+ &dev_attr_cache_type_ro);
+ if (err)
+ goto out_del_disk;
+ return 0;
+
+out_del_disk:
+ del_gendisk(vblk->disk);
+ blk_cleanup_queue(vblk->disk->queue);
+out_free_tags:
+ blk_mq_free_tag_set(&vblk->tag_set);
+out_put_disk:
+ put_disk(vblk->disk);
+out_free_vq:
+ vdev->config->del_vqs(vdev);
+out_free_vblk:
+ kfree(vblk);
+out_free_index:
+ ida_simple_remove(&vd_index_ida, index);
+out:
+ return err;
+}
+
+static void virtblk_remove(struct virtio_device *vdev)
+{
+ struct virtio_blk *vblk = vdev->priv;
+ int index = vblk->index;
+ int refc;
+
+ /* Make sure no work handler is accessing the device. */
+ flush_work(&vblk->config_work);
+
+ del_gendisk(vblk->disk);
+ blk_cleanup_queue(vblk->disk->queue);
+
+ blk_mq_free_tag_set(&vblk->tag_set);
+
+ /* Stop all the virtqueues. */
+ vdev->config->reset(vdev);
+
+ refc = atomic_read(&disk_to_dev(vblk->disk)->kobj.kref.refcount);
+ put_disk(vblk->disk);
+ vdev->config->del_vqs(vdev);
+ kfree(vblk->vqs);
+ kfree(vblk);
+
+ /* Only free device id if we don't have any users */
+ if (refc == 1)
+ ida_simple_remove(&vd_index_ida, index);
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int virtblk_freeze(struct virtio_device *vdev)
+{
+ struct virtio_blk *vblk = vdev->priv;
+
+ /* Ensure we don't receive any more interrupts */
+ vdev->config->reset(vdev);
+
+ /* Make sure no work handler is accessing the device. */
+ flush_work(&vblk->config_work);
+
+ blk_mq_stop_hw_queues(vblk->disk->queue);
+
+ vdev->config->del_vqs(vdev);
+ return 0;
+}
+
+static int virtblk_restore(struct virtio_device *vdev)
+{
+ struct virtio_blk *vblk = vdev->priv;
+ int ret;
+
+ ret = init_vq(vdev->priv);
+ if (ret)
+ return ret;
+
+ virtio_device_ready(vdev);
+
+ blk_mq_start_stopped_hw_queues(vblk->disk->queue, true);
+ return 0;
+}
+#endif
+
+static const struct virtio_device_id id_table[] = {
+ { VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID },
+ { 0 },
+};
+
+static unsigned int features_legacy[] = {
+ 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_WCE, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE,
+ VIRTIO_BLK_F_MQ,
+}
+;
+static unsigned int features[] = {
+ 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_TOPOLOGY,
+ VIRTIO_BLK_F_MQ,
+};
+
+static struct virtio_driver virtio_blk = {
+ .feature_table = features,
+ .feature_table_size = ARRAY_SIZE(features),
+ .feature_table_legacy = features_legacy,
+ .feature_table_size_legacy = ARRAY_SIZE(features_legacy),
+ .driver.name = KBUILD_MODNAME,
+ .driver.owner = THIS_MODULE,
+ .id_table = id_table,
+ .probe = virtblk_probe,
+ .remove = virtblk_remove,
+ .config_changed = virtblk_config_changed,
+#ifdef CONFIG_PM_SLEEP
+ .freeze = virtblk_freeze,
+ .restore = virtblk_restore,
+#endif
+};
+
+static int __init init(void)
+{
+ int error;
+
+ virtblk_wq = alloc_workqueue("virtio-blk", 0, 0);
+ if (!virtblk_wq)
+ return -ENOMEM;
+
+ major = register_blkdev(0, "virtblk");
+ if (major < 0) {
+ error = major;
+ goto out_destroy_workqueue;
+ }
+
+ error = register_virtio_driver(&virtio_blk);
+ if (error)
+ goto out_unregister_blkdev;
+ return 0;
+
+out_unregister_blkdev:
+ unregister_blkdev(major, "virtblk");
+out_destroy_workqueue:
+ destroy_workqueue(virtblk_wq);
+ return error;
+}
+
+static void __exit fini(void)
+{
+ unregister_virtio_driver(&virtio_blk);
+ unregister_blkdev(major, "virtblk");
+ destroy_workqueue(virtblk_wq);
+}
+module_init(init);
+module_exit(fini);
+
+MODULE_DEVICE_TABLE(virtio, id_table);
+MODULE_DESCRIPTION("Virtio block driver");
+MODULE_LICENSE("GPL");
Code Review / kvmfornfv.git / blobdiff