[deliverable/linux.git] / drivers / scsi / virtio_scsi.c

/*
 * Virtio SCSI HBA driver
 *
 * Copyright IBM Corp. 2010
 * Copyright Red Hat, Inc. 2011
 *
 * Authors:
 *  Stefan Hajnoczi   <stefanha@linux.vnet.ibm.com>
 *  Paolo Bonzini   <pbonzini@redhat.com>
 *
 * This work is licensed under the terms of the GNU GPL, version 2 or later.
 * See the COPYING file in the top-level directory.
 *
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/mempool.h>
#include <linux/virtio.h>
#include <linux/virtio_ids.h>
#include <linux/virtio_config.h>
#include <linux/virtio_scsi.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_cmnd.h>

#define VIRTIO_SCSI_MEMPOOL_SZ 64

/* Command queue element */
struct virtio_scsi_cmd {
	struct scsi_cmnd *sc;
	struct completion *comp;
	union {
		struct virtio_scsi_cmd_req       cmd;
		struct virtio_scsi_ctrl_tmf_req  tmf;
		struct virtio_scsi_ctrl_an_req   an;
	} req;
	union {
		struct virtio_scsi_cmd_resp      cmd;
		struct virtio_scsi_ctrl_tmf_resp tmf;
		struct virtio_scsi_ctrl_an_resp  an;
		struct virtio_scsi_event         evt;
	} resp;
} ____cacheline_aligned_in_smp;

/* Driver instance state */
struct virtio_scsi {
	/* Protects ctrl_vq, req_vq and sg[] */
	spinlock_t vq_lock;

	struct virtio_device *vdev;
	struct virtqueue *ctrl_vq;
	struct virtqueue *event_vq;
	struct virtqueue *req_vq;

	/* For sglist construction when adding commands to the virtqueue.  */
	struct scatterlist sg[];
};

static struct kmem_cache *virtscsi_cmd_cache;
static mempool_t *virtscsi_cmd_pool;

static inline struct Scsi_Host *virtio_scsi_host(struct virtio_device *vdev)
{
	return vdev->priv;
}

static void virtscsi_compute_resid(struct scsi_cmnd *sc, u32 resid)
{
	if (!resid)
		return;

	if (!scsi_bidi_cmnd(sc)) {
		scsi_set_resid(sc, resid);
		return;
	}

	scsi_in(sc)->resid = min(resid, scsi_in(sc)->length);
	scsi_out(sc)->resid = resid - scsi_in(sc)->resid;
}

/**
 * virtscsi_complete_cmd - finish a scsi_cmd and invoke scsi_done
 *
 * Called with vq_lock held.
 */
static void virtscsi_complete_cmd(void *buf)
{
	struct virtio_scsi_cmd *cmd = buf;
	struct scsi_cmnd *sc = cmd->sc;
	struct virtio_scsi_cmd_resp *resp = &cmd->resp.cmd;

	dev_dbg(&sc->device->sdev_gendev,
		"cmd %p response %u status %#02x sense_len %u\n",
		sc, resp->response, resp->status, resp->sense_len);

	sc->result = resp->status;
	virtscsi_compute_resid(sc, resp->resid);
	switch (resp->response) {
	case VIRTIO_SCSI_S_OK:
		set_host_byte(sc, DID_OK);
		break;
	case VIRTIO_SCSI_S_OVERRUN:
		set_host_byte(sc, DID_ERROR);
		break;
	case VIRTIO_SCSI_S_ABORTED:
		set_host_byte(sc, DID_ABORT);
		break;
	case VIRTIO_SCSI_S_BAD_TARGET:
		set_host_byte(sc, DID_BAD_TARGET);
		break;
	case VIRTIO_SCSI_S_RESET:
		set_host_byte(sc, DID_RESET);
		break;
	case VIRTIO_SCSI_S_BUSY:
		set_host_byte(sc, DID_BUS_BUSY);
		break;
	case VIRTIO_SCSI_S_TRANSPORT_FAILURE:
		set_host_byte(sc, DID_TRANSPORT_DISRUPTED);
		break;
	case VIRTIO_SCSI_S_TARGET_FAILURE:
		set_host_byte(sc, DID_TARGET_FAILURE);
		break;
	case VIRTIO_SCSI_S_NEXUS_FAILURE:
		set_host_byte(sc, DID_NEXUS_FAILURE);
		break;
	default:
		scmd_printk(KERN_WARNING, sc, "Unknown response %d",
			    resp->response);
		/* fall through */
	case VIRTIO_SCSI_S_FAILURE:
		set_host_byte(sc, DID_ERROR);
		break;
	}

	WARN_ON(resp->sense_len > VIRTIO_SCSI_SENSE_SIZE);
	if (sc->sense_buffer) {
		memcpy(sc->sense_buffer, resp->sense,
		       min_t(u32, resp->sense_len, VIRTIO_SCSI_SENSE_SIZE));
		if (resp->sense_len)
			set_driver_byte(sc, DRIVER_SENSE);
	}

	mempool_free(cmd, virtscsi_cmd_pool);
	sc->scsi_done(sc);
}

static void virtscsi_vq_done(struct virtqueue *vq, void (*fn)(void *buf))
{
	struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
	struct virtio_scsi *vscsi = shost_priv(sh);
	void *buf;
	unsigned long flags;
	unsigned int len;

	spin_lock_irqsave(&vscsi->vq_lock, flags);

	do {
		virtqueue_disable_cb(vq);
		while ((buf = virtqueue_get_buf(vq, &len)) != NULL)
			fn(buf);
	} while (!virtqueue_enable_cb(vq));

	spin_unlock_irqrestore(&vscsi->vq_lock, flags);
}

static void virtscsi_req_done(struct virtqueue *vq)
{
	virtscsi_vq_done(vq, virtscsi_complete_cmd);
};

static void virtscsi_complete_free(void *buf)
{
	struct virtio_scsi_cmd *cmd = buf;

	if (cmd->comp)
		complete_all(cmd->comp);
	else
		mempool_free(cmd, virtscsi_cmd_pool);
}

static void virtscsi_ctrl_done(struct virtqueue *vq)
{
	virtscsi_vq_done(vq, virtscsi_complete_free);
};

static void virtscsi_event_done(struct virtqueue *vq)
{
	virtscsi_vq_done(vq, virtscsi_complete_free);
};

static void virtscsi_map_sgl(struct scatterlist *sg, unsigned int *p_idx,
			     struct scsi_data_buffer *sdb)
{
	struct sg_table *table = &sdb->table;
	struct scatterlist *sg_elem;
	unsigned int idx = *p_idx;
	int i;

	for_each_sg(table->sgl, sg_elem, table->nents, i)
		sg_set_buf(&sg[idx++], sg_virt(sg_elem), sg_elem->length);

	*p_idx = idx;
}

/**
 * virtscsi_map_cmd - map a scsi_cmd to a virtqueue scatterlist
 * @vscsi	: virtio_scsi state
 * @cmd		: command structure
 * @out_num	: number of read-only elements
 * @in_num	: number of write-only elements
 * @req_size	: size of the request buffer
 * @resp_size	: size of the response buffer
 *
 * Called with vq_lock held.
 */
static void virtscsi_map_cmd(struct virtio_scsi *vscsi,
			     struct virtio_scsi_cmd *cmd,
			     unsigned *out_num, unsigned *in_num,
			     size_t req_size, size_t resp_size)
{
	struct scsi_cmnd *sc = cmd->sc;
	struct scatterlist *sg = vscsi->sg;
	unsigned int idx = 0;

	if (sc) {
		struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
		BUG_ON(scsi_sg_count(sc) > shost->sg_tablesize);

		/* TODO: check feature bit and fail if unsupported?  */
		BUG_ON(sc->sc_data_direction == DMA_BIDIRECTIONAL);
	}

	/* Request header.  */
	sg_set_buf(&sg[idx++], &cmd->req, req_size);

	/* Data-out buffer.  */
	if (sc && sc->sc_data_direction != DMA_FROM_DEVICE)
		virtscsi_map_sgl(sg, &idx, scsi_out(sc));

	*out_num = idx;

	/* Response header.  */
	sg_set_buf(&sg[idx++], &cmd->resp, resp_size);

	/* Data-in buffer */
	if (sc && sc->sc_data_direction != DMA_TO_DEVICE)
		virtscsi_map_sgl(sg, &idx, scsi_in(sc));

	*in_num = idx - *out_num;
}

static int virtscsi_kick_cmd(struct virtio_scsi *vscsi, struct virtqueue *vq,
			     struct virtio_scsi_cmd *cmd,
			     size_t req_size, size_t resp_size, gfp_t gfp)
{
	unsigned int out_num, in_num;
	unsigned long flags;
	int ret;

	spin_lock_irqsave(&vscsi->vq_lock, flags);

	virtscsi_map_cmd(vscsi, cmd, &out_num, &in_num, req_size, resp_size);

	ret = virtqueue_add_buf(vq, vscsi->sg, out_num, in_num, cmd, gfp);
	if (ret >= 0)
		virtqueue_kick(vq);

	spin_unlock_irqrestore(&vscsi->vq_lock, flags);
	return ret;
}

static int virtscsi_queuecommand(struct Scsi_Host *sh, struct scsi_cmnd *sc)
{
	struct virtio_scsi *vscsi = shost_priv(sh);
	struct virtio_scsi_cmd *cmd;
	int ret;

	dev_dbg(&sc->device->sdev_gendev,
		"cmd %p CDB: %#02x\n", sc, sc->cmnd[0]);

	ret = SCSI_MLQUEUE_HOST_BUSY;
	cmd = mempool_alloc(virtscsi_cmd_pool, GFP_ATOMIC);
	if (!cmd)
		goto out;

	memset(cmd, 0, sizeof(*cmd));
	cmd->sc = sc;
	cmd->req.cmd = (struct virtio_scsi_cmd_req){
		.lun[0] = 1,
		.lun[1] = sc->device->id,
		.lun[2] = (sc->device->lun >> 8) | 0x40,
		.lun[3] = sc->device->lun & 0xff,
		.tag = (unsigned long)sc,
		.task_attr = VIRTIO_SCSI_S_SIMPLE,
		.prio = 0,
		.crn = 0,
	};

	BUG_ON(sc->cmd_len > VIRTIO_SCSI_CDB_SIZE);
	memcpy(cmd->req.cmd.cdb, sc->cmnd, sc->cmd_len);

	if (virtscsi_kick_cmd(vscsi, vscsi->req_vq, cmd,
			      sizeof cmd->req.cmd, sizeof cmd->resp.cmd,
			      GFP_ATOMIC) >= 0)
		ret = 0;

out:
	return ret;
}

static int virtscsi_tmf(struct virtio_scsi *vscsi, struct virtio_scsi_cmd *cmd)
{
	DECLARE_COMPLETION_ONSTACK(comp);
	int ret = FAILED;

	cmd->comp = &comp;
	if (virtscsi_kick_cmd(vscsi, vscsi->ctrl_vq, cmd,
			      sizeof cmd->req.tmf, sizeof cmd->resp.tmf,
			      GFP_NOIO) < 0)
		goto out;

	wait_for_completion(&comp);
	if (cmd->resp.tmf.response == VIRTIO_SCSI_S_OK ||
	    cmd->resp.tmf.response == VIRTIO_SCSI_S_FUNCTION_SUCCEEDED)
		ret = SUCCESS;

out:
	mempool_free(cmd, virtscsi_cmd_pool);
	return ret;
}

static int virtscsi_device_reset(struct scsi_cmnd *sc)
{
	struct virtio_scsi *vscsi = shost_priv(sc->device->host);
	struct virtio_scsi_cmd *cmd;

	sdev_printk(KERN_INFO, sc->device, "device reset\n");
	cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO);
	if (!cmd)
		return FAILED;

	memset(cmd, 0, sizeof(*cmd));
	cmd->sc = sc;
	cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){
		.type = VIRTIO_SCSI_T_TMF,
		.subtype = VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET,
		.lun[0] = 1,
		.lun[1] = sc->device->id,
		.lun[2] = (sc->device->lun >> 8) | 0x40,
		.lun[3] = sc->device->lun & 0xff,
	};
	return virtscsi_tmf(vscsi, cmd);
}

static int virtscsi_abort(struct scsi_cmnd *sc)
{
	struct virtio_scsi *vscsi = shost_priv(sc->device->host);
	struct virtio_scsi_cmd *cmd;

	scmd_printk(KERN_INFO, sc, "abort\n");
	cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO);
	if (!cmd)
		return FAILED;

	memset(cmd, 0, sizeof(*cmd));
	cmd->sc = sc;
	cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){
		.type = VIRTIO_SCSI_T_TMF,
		.subtype = VIRTIO_SCSI_T_TMF_ABORT_TASK,
		.lun[0] = 1,
		.lun[1] = sc->device->id,
		.lun[2] = (sc->device->lun >> 8) | 0x40,
		.lun[3] = sc->device->lun & 0xff,
		.tag = (unsigned long)sc,
	};
	return virtscsi_tmf(vscsi, cmd);
}

static struct scsi_host_template virtscsi_host_template = {
	.module = THIS_MODULE,
	.name = "Virtio SCSI HBA",
	.proc_name = "virtio_scsi",
	.queuecommand = virtscsi_queuecommand,
	.this_id = -1,
	.eh_abort_handler = virtscsi_abort,
	.eh_device_reset_handler = virtscsi_device_reset,

	.can_queue = 1024,
	.dma_boundary = UINT_MAX,
	.use_clustering = ENABLE_CLUSTERING,
};

#define virtscsi_config_get(vdev, fld) \
	({ \
		typeof(((struct virtio_scsi_config *)0)->fld) __val; \
		vdev->config->get(vdev, \
				  offsetof(struct virtio_scsi_config, fld), \
				  &__val, sizeof(__val)); \
		__val; \
	})

#define virtscsi_config_set(vdev, fld, val) \
	(void)({ \
		typeof(((struct virtio_scsi_config *)0)->fld) __val = (val); \
		vdev->config->set(vdev, \
				  offsetof(struct virtio_scsi_config, fld), \
				  &__val, sizeof(__val)); \
	})

static int virtscsi_init(struct virtio_device *vdev,
			 struct virtio_scsi *vscsi)
{
	int err;
	struct virtqueue *vqs[3];
	vq_callback_t *callbacks[] = {
		virtscsi_ctrl_done,
		virtscsi_event_done,
		virtscsi_req_done
	};
	const char *names[] = {
		"control",
		"event",
		"request"
	};

	/* Discover virtqueues and write information to configuration.  */
	err = vdev->config->find_vqs(vdev, 3, vqs, callbacks, names);
	if (err)
		return err;

	vscsi->ctrl_vq = vqs[0];
	vscsi->event_vq = vqs[1];
	vscsi->req_vq = vqs[2];

	virtscsi_config_set(vdev, cdb_size, VIRTIO_SCSI_CDB_SIZE);
	virtscsi_config_set(vdev, sense_size, VIRTIO_SCSI_SENSE_SIZE);
	return 0;
}

static int __devinit virtscsi_probe(struct virtio_device *vdev)
{
	struct Scsi_Host *shost;
	struct virtio_scsi *vscsi;
	int err;
	u32 sg_elems;
	u32 cmd_per_lun;

	/* We need to know how many segments before we allocate.
	 * We need an extra sg elements at head and tail.
	 */
	sg_elems = virtscsi_config_get(vdev, seg_max) ?: 1;

	/* Allocate memory and link the structs together.  */
	shost = scsi_host_alloc(&virtscsi_host_template,
		sizeof(*vscsi) + sizeof(vscsi->sg[0]) * (sg_elems + 2));

	if (!shost)
		return -ENOMEM;

	shost->sg_tablesize = sg_elems;
	vscsi = shost_priv(shost);
	vscsi->vdev = vdev;
	vdev->priv = shost;

	/* Random initializations.  */
	spin_lock_init(&vscsi->vq_lock);
	sg_init_table(vscsi->sg, sg_elems + 2);

	err = virtscsi_init(vdev, vscsi);
	if (err)
		goto virtscsi_init_failed;

	cmd_per_lun = virtscsi_config_get(vdev, cmd_per_lun) ?: 1;
	shost->cmd_per_lun = min_t(u32, cmd_per_lun, shost->can_queue);
	shost->max_sectors = virtscsi_config_get(vdev, max_sectors) ?: 0xFFFF;
	shost->max_lun = virtscsi_config_get(vdev, max_lun) + 1;
	shost->max_id = virtscsi_config_get(vdev, max_target) + 1;
	shost->max_channel = 0;
	shost->max_cmd_len = VIRTIO_SCSI_CDB_SIZE;
	err = scsi_add_host(shost, &vdev->dev);
	if (err)
		goto scsi_add_host_failed;

	scsi_scan_host(shost);

	return 0;

scsi_add_host_failed:
	vdev->config->del_vqs(vdev);
virtscsi_init_failed:
	scsi_host_put(shost);
	return err;
}

static void virtscsi_remove_vqs(struct virtio_device *vdev)
{
	/* Stop all the virtqueues. */
	vdev->config->reset(vdev);

	vdev->config->del_vqs(vdev);
}

static void __devexit virtscsi_remove(struct virtio_device *vdev)
{
	struct Scsi_Host *shost = virtio_scsi_host(vdev);

	scsi_remove_host(shost);

	virtscsi_remove_vqs(vdev);
	scsi_host_put(shost);
}

#ifdef CONFIG_PM
static int virtscsi_freeze(struct virtio_device *vdev)
{
	virtscsi_remove_vqs(vdev);
	return 0;
}

static int virtscsi_restore(struct virtio_device *vdev)
{
	struct Scsi_Host *sh = virtio_scsi_host(vdev);
	struct virtio_scsi *vscsi = shost_priv(sh);

	return virtscsi_init(vdev, vscsi);
}
#endif

static struct virtio_device_id id_table[] = {
	{ VIRTIO_ID_SCSI, VIRTIO_DEV_ANY_ID },
	{ 0 },
};

static struct virtio_driver virtio_scsi_driver = {
	.driver.name = KBUILD_MODNAME,
	.driver.owner = THIS_MODULE,
	.id_table = id_table,
	.probe = virtscsi_probe,
#ifdef CONFIG_PM
	.freeze = virtscsi_freeze,
	.restore = virtscsi_restore,
#endif
	.remove = __devexit_p(virtscsi_remove),
};

static int __init init(void)
{
	int ret = -ENOMEM;

	virtscsi_cmd_cache = KMEM_CACHE(virtio_scsi_cmd, 0);
	if (!virtscsi_cmd_cache) {
		printk(KERN_ERR "kmem_cache_create() for "
				"virtscsi_cmd_cache failed\n");
		goto error;
	}


	virtscsi_cmd_pool =
		mempool_create_slab_pool(VIRTIO_SCSI_MEMPOOL_SZ,
					 virtscsi_cmd_cache);
	if (!virtscsi_cmd_pool) {
		printk(KERN_ERR "mempool_create() for"
				"virtscsi_cmd_pool failed\n");
		goto error;
	}
	ret = register_virtio_driver(&virtio_scsi_driver);
	if (ret < 0)
		goto error;

	return 0;

error:
	if (virtscsi_cmd_pool) {
		mempool_destroy(virtscsi_cmd_pool);
		virtscsi_cmd_pool = NULL;
	}
	if (virtscsi_cmd_cache) {
		kmem_cache_destroy(virtscsi_cmd_cache);
		virtscsi_cmd_cache = NULL;
	}
	return ret;
}

static void __exit fini(void)
{
	unregister_virtio_driver(&virtio_scsi_driver);
	mempool_destroy(virtscsi_cmd_pool);
	kmem_cache_destroy(virtscsi_cmd_cache);
}
module_init(init);
module_exit(fini);

MODULE_DEVICE_TABLE(virtio, id_table);
MODULE_DESCRIPTION("Virtio SCSI HBA driver");
MODULE_LICENSE("GPL");
Commit	Line	Data
4fe74b1c PB	1	/*
	2	* Virtio SCSI HBA driver
	3	*
	4	* Copyright IBM Corp. 2010
	5	* Copyright Red Hat, Inc. 2011
	6	*
	7	* Authors:
	8	* Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
	9	* Paolo Bonzini <pbonzini@redhat.com>
	10	*
	11	* This work is licensed under the terms of the GNU GPL, version 2 or later.
	12	* See the COPYING file in the top-level directory.
	13	*
	14	*/
	15
	16	#include <linux/module.h>
	17	#include <linux/slab.h>
	18	#include <linux/mempool.h>
	19	#include <linux/virtio.h>
	20	#include <linux/virtio_ids.h>
	21	#include <linux/virtio_config.h>
	22	#include <linux/virtio_scsi.h>
	23	#include <scsi/scsi_host.h>
	24	#include <scsi/scsi_device.h>
	25	#include <scsi/scsi_cmnd.h>
	26
	27	#define VIRTIO_SCSI_MEMPOOL_SZ 64
	28
	29	/* Command queue element */
	30	struct virtio_scsi_cmd {
	31	struct scsi_cmnd *sc;
	32	struct completion *comp;
	33	union {
	34	struct virtio_scsi_cmd_req cmd;
	35	struct virtio_scsi_ctrl_tmf_req tmf;
	36	struct virtio_scsi_ctrl_an_req an;
	37	} req;
	38	union {
	39	struct virtio_scsi_cmd_resp cmd;
	40	struct virtio_scsi_ctrl_tmf_resp tmf;
	41	struct virtio_scsi_ctrl_an_resp an;
	42	struct virtio_scsi_event evt;
	43	} resp;
	44	} ____cacheline_aligned_in_smp;
	45
	46	/* Driver instance state */
	47	struct virtio_scsi {
	48	/* Protects ctrl_vq, req_vq and sg[] */
	49	spinlock_t vq_lock;
	50
	51	struct virtio_device *vdev;
	52	struct virtqueue *ctrl_vq;
	53	struct virtqueue *event_vq;
	54	struct virtqueue *req_vq;
	55
	56	/* For sglist construction when adding commands to the virtqueue. */
	57	struct scatterlist sg[];
	58	};
	59
	60	static struct kmem_cache *virtscsi_cmd_cache;
	61	static mempool_t *virtscsi_cmd_pool;
	62
	63	static inline struct Scsi_Host virtio_scsi_host(struct virtio_device vdev)
	64	{
65	return vdev->priv;
66	}
67
68	static void virtscsi_compute_resid(struct scsi_cmnd *sc, u32 resid)
69	{
70	if (!resid)
71	return;
72
73	if (!scsi_bidi_cmnd(sc)) {
74	scsi_set_resid(sc, resid);
75	return;
76	}
77
78	scsi_in(sc)->resid = min(resid, scsi_in(sc)->length);
79	scsi_out(sc)->resid = resid - scsi_in(sc)->resid;
80	}
81
82	/**
83	* virtscsi_complete_cmd - finish a scsi_cmd and invoke scsi_done
84	*
85	* Called with vq_lock held.
86	*/
87	static void virtscsi_complete_cmd(void *buf)
88	{
89	struct virtio_scsi_cmd *cmd = buf;
90	struct scsi_cmnd *sc = cmd->sc;
91	struct virtio_scsi_cmd_resp *resp = &cmd->resp.cmd;
92
93	dev_dbg(&sc->device->sdev_gendev,
94	"cmd %p response %u status %#02x sense_len %u\n",
95	sc, resp->response, resp->status, resp->sense_len);
96
97	sc->result = resp->status;
98	virtscsi_compute_resid(sc, resp->resid);
99	switch (resp->response) {
100	case VIRTIO_SCSI_S_OK:
101	set_host_byte(sc, DID_OK);
102	break;
103	case VIRTIO_SCSI_S_OVERRUN:
104	set_host_byte(sc, DID_ERROR);
105	break;
106	case VIRTIO_SCSI_S_ABORTED:
107	set_host_byte(sc, DID_ABORT);
108	break;
109	case VIRTIO_SCSI_S_BAD_TARGET:
110	set_host_byte(sc, DID_BAD_TARGET);
111	break;
112	case VIRTIO_SCSI_S_RESET:
113	set_host_byte(sc, DID_RESET);
114	break;
115	case VIRTIO_SCSI_S_BUSY:
116	set_host_byte(sc, DID_BUS_BUSY);
117	break;
118	case VIRTIO_SCSI_S_TRANSPORT_FAILURE:
119	set_host_byte(sc, DID_TRANSPORT_DISRUPTED);
120	break;
121	case VIRTIO_SCSI_S_TARGET_FAILURE:
122	set_host_byte(sc, DID_TARGET_FAILURE);
123	break;
124	case VIRTIO_SCSI_S_NEXUS_FAILURE:
125	set_host_byte(sc, DID_NEXUS_FAILURE);
126	break;
127	default:
128	scmd_printk(KERN_WARNING, sc, "Unknown response %d",
129	resp->response);
130	/* fall through */
131	case VIRTIO_SCSI_S_FAILURE:
132	set_host_byte(sc, DID_ERROR);
133	break;
134	}
135
136	WARN_ON(resp->sense_len > VIRTIO_SCSI_SENSE_SIZE);
137	if (sc->sense_buffer) {
138	memcpy(sc->sense_buffer, resp->sense,
139	min_t(u32, resp->sense_len, VIRTIO_SCSI_SENSE_SIZE));
140	if (resp->sense_len)
141	set_driver_byte(sc, DRIVER_SENSE);
142	}
143
144	mempool_free(cmd, virtscsi_cmd_pool);
145	sc->scsi_done(sc);
146	}
147
148	static void virtscsi_vq_done(struct virtqueue vq, void (fn)(void *buf))
149	{
150	struct Scsi_Host *sh = virtio_scsi_host(vq->vdev);
151	struct virtio_scsi *vscsi = shost_priv(sh);
152	void *buf;
153	unsigned long flags;
154	unsigned int len;
155
156	spin_lock_irqsave(&vscsi->vq_lock, flags);
157
158	do {
159	virtqueue_disable_cb(vq);
160	while ((buf = virtqueue_get_buf(vq, &len)) != NULL)
161	fn(buf);
162	} while (!virtqueue_enable_cb(vq));
163
164	spin_unlock_irqrestore(&vscsi->vq_lock, flags);
165	}
166
167	static void virtscsi_req_done(struct virtqueue *vq)
168	{
169	virtscsi_vq_done(vq, virtscsi_complete_cmd);
170	};
171
172	static void virtscsi_complete_free(void *buf)
173	{
174	struct virtio_scsi_cmd *cmd = buf;
175
176	if (cmd->comp)
177	complete_all(cmd->comp);
e4594bb5 PB	178	else
e4594bb5 PB	179	mempool_free(cmd, virtscsi_cmd_pool);
4fe74b1c PB	180	}
	181
	182	static void virtscsi_ctrl_done(struct virtqueue *vq)
	183	{
	184	virtscsi_vq_done(vq, virtscsi_complete_free);
	185	};
	186
	187	static void virtscsi_event_done(struct virtqueue *vq)
	188	{
	189	virtscsi_vq_done(vq, virtscsi_complete_free);
	190	};
	191
	192	static void virtscsi_map_sgl(struct scatterlist sg, unsigned int p_idx,
	193	struct scsi_data_buffer *sdb)
	194	{
	195	struct sg_table *table = &sdb->table;
	196	struct scatterlist *sg_elem;
	197	unsigned int idx = *p_idx;
	198	int i;
	199
	200	for_each_sg(table->sgl, sg_elem, table->nents, i)
	201	sg_set_buf(&sg[idx++], sg_virt(sg_elem), sg_elem->length);
	202
	203	*p_idx = idx;
	204	}
	205
	206	/**
	207	* virtscsi_map_cmd - map a scsi_cmd to a virtqueue scatterlist
	208	* @vscsi : virtio_scsi state
	209	* @cmd : command structure
	210	* @out_num : number of read-only elements
	211	* @in_num : number of write-only elements
	212	* @req_size : size of the request buffer
	213	* @resp_size : size of the response buffer
	214	*
	215	* Called with vq_lock held.
	216	*/
	217	static void virtscsi_map_cmd(struct virtio_scsi *vscsi,
	218	struct virtio_scsi_cmd *cmd,
	219	unsigned out_num, unsigned in_num,
	220	size_t req_size, size_t resp_size)
	221	{
	222	struct scsi_cmnd *sc = cmd->sc;
	223	struct scatterlist *sg = vscsi->sg;
	224	unsigned int idx = 0;
	225
	226	if (sc) {
	227	struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
	228	BUG_ON(scsi_sg_count(sc) > shost->sg_tablesize);
	229
	230	/* TODO: check feature bit and fail if unsupported? */
	231	BUG_ON(sc->sc_data_direction == DMA_BIDIRECTIONAL);
	232	}
	233
	234	/* Request header. */
	235	sg_set_buf(&sg[idx++], &cmd->req, req_size);
	236
	237	/* Data-out buffer. */
	238	if (sc && sc->sc_data_direction != DMA_FROM_DEVICE)
	239	virtscsi_map_sgl(sg, &idx, scsi_out(sc));
	240
	241	*out_num = idx;
	242
	243	/* Response header. */
244	sg_set_buf(&sg[idx++], &cmd->resp, resp_size);
245
246	/* Data-in buffer */
247	if (sc && sc->sc_data_direction != DMA_TO_DEVICE)
248	virtscsi_map_sgl(sg, &idx, scsi_in(sc));
249
250	in_num = idx - out_num;
251	}
252
253	static int virtscsi_kick_cmd(struct virtio_scsi vscsi, struct virtqueue vq,
254	struct virtio_scsi_cmd *cmd,
255	size_t req_size, size_t resp_size, gfp_t gfp)
256	{
257	unsigned int out_num, in_num;
258	unsigned long flags;
259	int ret;
260
261	spin_lock_irqsave(&vscsi->vq_lock, flags);
262
263	virtscsi_map_cmd(vscsi, cmd, &out_num, &in_num, req_size, resp_size);
264
265	ret = virtqueue_add_buf(vq, vscsi->sg, out_num, in_num, cmd, gfp);
266	if (ret >= 0)
267	virtqueue_kick(vq);
268
269	spin_unlock_irqrestore(&vscsi->vq_lock, flags);
270	return ret;
271	}
272
273	static int virtscsi_queuecommand(struct Scsi_Host sh, struct scsi_cmnd sc)
274	{
275	struct virtio_scsi *vscsi = shost_priv(sh);
276	struct virtio_scsi_cmd *cmd;
277	int ret;
278
279	dev_dbg(&sc->device->sdev_gendev,
280	"cmd %p CDB: %#02x\n", sc, sc->cmnd[0]);
281
282	ret = SCSI_MLQUEUE_HOST_BUSY;
283	cmd = mempool_alloc(virtscsi_cmd_pool, GFP_ATOMIC);
284	if (!cmd)
285	goto out;
286
287	memset(cmd, 0, sizeof(*cmd));
288	cmd->sc = sc;
289	cmd->req.cmd = (struct virtio_scsi_cmd_req){
290	.lun[0] = 1,
291	.lun[1] = sc->device->id,
292	.lun[2] = (sc->device->lun >> 8) \| 0x40,
293	.lun[3] = sc->device->lun & 0xff,
294	.tag = (unsigned long)sc,
295	.task_attr = VIRTIO_SCSI_S_SIMPLE,
296	.prio = 0,
297	.crn = 0,
298	};
299
300	BUG_ON(sc->cmd_len > VIRTIO_SCSI_CDB_SIZE);
301	memcpy(cmd->req.cmd.cdb, sc->cmnd, sc->cmd_len);
302
303	if (virtscsi_kick_cmd(vscsi, vscsi->req_vq, cmd,
304	sizeof cmd->req.cmd, sizeof cmd->resp.cmd,
305	GFP_ATOMIC) >= 0)
306	ret = 0;
307
308	out:
309	return ret;
310	}
311
312	static int virtscsi_tmf(struct virtio_scsi vscsi, struct virtio_scsi_cmd cmd)
313	{
314	DECLARE_COMPLETION_ONSTACK(comp);
e4594bb5	315	int ret = FAILED;
4fe74b1c PB	316
4fe74b1c PB	317	cmd->comp = &comp;
e4594bb5 PB	318	if (virtscsi_kick_cmd(vscsi, vscsi->ctrl_vq, cmd,
	319	sizeof cmd->req.tmf, sizeof cmd->resp.tmf,
	320	GFP_NOIO) < 0)
	321	goto out;
4fe74b1c PB	322
4fe74b1c PB	323	wait_for_completion(&comp);
e4594bb5 PB	324	if (cmd->resp.tmf.response == VIRTIO_SCSI_S_OK \|\|
	325	cmd->resp.tmf.response == VIRTIO_SCSI_S_FUNCTION_SUCCEEDED)
	326	ret = SUCCESS;
4fe74b1c	327
e4594bb5 PB	328	out:
	329	mempool_free(cmd, virtscsi_cmd_pool);
	330	return ret;
4fe74b1c PB	331	}
	332
	333	static int virtscsi_device_reset(struct scsi_cmnd *sc)
	334	{
	335	struct virtio_scsi *vscsi = shost_priv(sc->device->host);
	336	struct virtio_scsi_cmd *cmd;
	337
	338	sdev_printk(KERN_INFO, sc->device, "device reset\n");
	339	cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO);
	340	if (!cmd)
	341	return FAILED;
	342
	343	memset(cmd, 0, sizeof(*cmd));
	344	cmd->sc = sc;
	345	cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){
	346	.type = VIRTIO_SCSI_T_TMF,
	347	.subtype = VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET,
	348	.lun[0] = 1,
	349	.lun[1] = sc->device->id,
	350	.lun[2] = (sc->device->lun >> 8) \| 0x40,
	351	.lun[3] = sc->device->lun & 0xff,
	352	};
	353	return virtscsi_tmf(vscsi, cmd);
	354	}
	355
	356	static int virtscsi_abort(struct scsi_cmnd *sc)
	357	{
	358	struct virtio_scsi *vscsi = shost_priv(sc->device->host);
	359	struct virtio_scsi_cmd *cmd;
	360
	361	scmd_printk(KERN_INFO, sc, "abort\n");
	362	cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO);
	363	if (!cmd)
	364	return FAILED;
	365
	366	memset(cmd, 0, sizeof(*cmd));
	367	cmd->sc = sc;
	368	cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){
	369	.type = VIRTIO_SCSI_T_TMF,
	370	.subtype = VIRTIO_SCSI_T_TMF_ABORT_TASK,
	371	.lun[0] = 1,
	372	.lun[1] = sc->device->id,
	373	.lun[2] = (sc->device->lun >> 8) \| 0x40,
	374	.lun[3] = sc->device->lun & 0xff,
	375	.tag = (unsigned long)sc,
	376	};
	377	return virtscsi_tmf(vscsi, cmd);
	378	}
	379
	380	static struct scsi_host_template virtscsi_host_template = {
	381	.module = THIS_MODULE,
	382	.name = "Virtio SCSI HBA",
	383	.proc_name = "virtio_scsi",
	384	.queuecommand = virtscsi_queuecommand,
	385	.this_id = -1,
	386	.eh_abort_handler = virtscsi_abort,
	387	.eh_device_reset_handler = virtscsi_device_reset,
	388
	389	.can_queue = 1024,
	390	.dma_boundary = UINT_MAX,
	391	.use_clustering = ENABLE_CLUSTERING,
	392	};
	393
	394	#define virtscsi_config_get(vdev, fld) \
395	({ \
396	typeof(((struct virtio_scsi_config *)0)->fld) __val; \
397	vdev->config->get(vdev, \
398	offsetof(struct virtio_scsi_config, fld), \
399	&__val, sizeof(__val)); \
400	__val; \
401	})
402
403	#define virtscsi_config_set(vdev, fld, val) \
404	(void)({ \
405	typeof(((struct virtio_scsi_config *)0)->fld) __val = (val); \
406	vdev->config->set(vdev, \
407	offsetof(struct virtio_scsi_config, fld), \
408	&__val, sizeof(__val)); \
409	})
410
411	static int virtscsi_init(struct virtio_device *vdev,
412	struct virtio_scsi *vscsi)
413	{
414	int err;
415	struct virtqueue *vqs[3];
416	vq_callback_t *callbacks[] = {
417	virtscsi_ctrl_done,
418	virtscsi_event_done,
419	virtscsi_req_done
420	};
421	const char *names[] = {
422	"control",
423	"event",
424	"request"
425	};
426
427	/* Discover virtqueues and write information to configuration. */
428	err = vdev->config->find_vqs(vdev, 3, vqs, callbacks, names);
429	if (err)
430	return err;
431
432	vscsi->ctrl_vq = vqs[0];
433	vscsi->event_vq = vqs[1];
434	vscsi->req_vq = vqs[2];
435
436	virtscsi_config_set(vdev, cdb_size, VIRTIO_SCSI_CDB_SIZE);
437	virtscsi_config_set(vdev, sense_size, VIRTIO_SCSI_SENSE_SIZE);
438	return 0;
439	}
440
441	static int __devinit virtscsi_probe(struct virtio_device *vdev)
442	{
443	struct Scsi_Host *shost;
444	struct virtio_scsi *vscsi;
445	int err;
446	u32 sg_elems;
447	u32 cmd_per_lun;
448
449	/* We need to know how many segments before we allocate.
450	* We need an extra sg elements at head and tail.
451	*/
452	sg_elems = virtscsi_config_get(vdev, seg_max) ?: 1;
453
454	/* Allocate memory and link the structs together. */
455	shost = scsi_host_alloc(&virtscsi_host_template,
456	sizeof(vscsi) + sizeof(vscsi->sg[0]) (sg_elems + 2));
457
458	if (!shost)
459	return -ENOMEM;
460
461	shost->sg_tablesize = sg_elems;
462	vscsi = shost_priv(shost);
463	vscsi->vdev = vdev;
464	vdev->priv = shost;
465
466	/* Random initializations. */
467	spin_lock_init(&vscsi->vq_lock);
468	sg_init_table(vscsi->sg, sg_elems + 2);
469
470	err = virtscsi_init(vdev, vscsi);
471	if (err)
472	goto virtscsi_init_failed;
473
474	cmd_per_lun = virtscsi_config_get(vdev, cmd_per_lun) ?: 1;
475	shost->cmd_per_lun = min_t(u32, cmd_per_lun, shost->can_queue);
476	shost->max_sectors = virtscsi_config_get(vdev, max_sectors) ?: 0xFFFF;
477	shost->max_lun = virtscsi_config_get(vdev, max_lun) + 1;
478	shost->max_id = virtscsi_config_get(vdev, max_target) + 1;
479	shost->max_channel = 0;
480	shost->max_cmd_len = VIRTIO_SCSI_CDB_SIZE;
481	err = scsi_add_host(shost, &vdev->dev);
482	if (err)
483	goto scsi_add_host_failed;
484
485	scsi_scan_host(shost);
486
487	return 0;
488
489	scsi_add_host_failed:
490	vdev->config->del_vqs(vdev);
491	virtscsi_init_failed:
492	scsi_host_put(shost);
493	return err;
494	}
495
496	static void virtscsi_remove_vqs(struct virtio_device *vdev)
497	{
498	/* Stop all the virtqueues. */
499	vdev->config->reset(vdev);
500
501	vdev->config->del_vqs(vdev);
502	}
503
504	static void __devexit virtscsi_remove(struct virtio_device *vdev)
505	{
506	struct Scsi_Host *shost = virtio_scsi_host(vdev);
507
508	scsi_remove_host(shost);
509
510	virtscsi_remove_vqs(vdev);
511	scsi_host_put(shost);
512	}
513
514	#ifdef CONFIG_PM
515	static int virtscsi_freeze(struct virtio_device *vdev)
516	{
517	virtscsi_remove_vqs(vdev);
518	return 0;
519	}
520
521	static int virtscsi_restore(struct virtio_device *vdev)
522	{
523	struct Scsi_Host *sh = virtio_scsi_host(vdev);
524	struct virtio_scsi *vscsi = shost_priv(sh);
525
526	return virtscsi_init(vdev, vscsi);
527	}
528	#endif
529
530	static struct virtio_device_id id_table[] = {
531	{ VIRTIO_ID_SCSI, VIRTIO_DEV_ANY_ID },
532	{ 0 },
533	};
534
535	static struct virtio_driver virtio_scsi_driver = {
536	.driver.name = KBUILD_MODNAME,
537	.driver.owner = THIS_MODULE,
538	.id_table = id_table,
539	.probe = virtscsi_probe,
540	#ifdef CONFIG_PM
541	.freeze = virtscsi_freeze,
542	.restore = virtscsi_restore,
543	#endif
544	.remove = __devexit_p(virtscsi_remove),
545	};
546
547	static int __init init(void)
548	{
549	int ret = -ENOMEM;
550
551	virtscsi_cmd_cache = KMEM_CACHE(virtio_scsi_cmd, 0);
552	if (!virtscsi_cmd_cache) {
553	printk(KERN_ERR "kmem_cache_create() for "
554	"virtscsi_cmd_cache failed\n");
555	goto error;
556	}
557
558
559	virtscsi_cmd_pool =
560	mempool_create_slab_pool(VIRTIO_SCSI_MEMPOOL_SZ,
561	virtscsi_cmd_cache);
562	if (!virtscsi_cmd_pool) {
563	printk(KERN_ERR "mempool_create() for"
564	"virtscsi_cmd_pool failed\n");
565	goto error;
566	}
567	ret = register_virtio_driver(&virtio_scsi_driver);
568	if (ret < 0)
569	goto error;
570
571	return 0;
572
573	error:
574	if (virtscsi_cmd_pool) {
575	mempool_destroy(virtscsi_cmd_pool);
576	virtscsi_cmd_pool = NULL;
577	}
578	if (virtscsi_cmd_cache) {
579	kmem_cache_destroy(virtscsi_cmd_cache);
580	virtscsi_cmd_cache = NULL;
581	}
582	return ret;
583	}
584
585	static void __exit fini(void)
586	{
587	unregister_virtio_driver(&virtio_scsi_driver);
588	mempool_destroy(virtscsi_cmd_pool);
589	kmem_cache_destroy(virtscsi_cmd_cache);
590	}
591	module_init(init);
592	module_exit(fini);
593
594	MODULE_DEVICE_TABLE(virtio, id_table);
595	MODULE_DESCRIPTION("Virtio SCSI HBA driver");
596	MODULE_LICENSE("GPL");