[net-next-2.6.git] / drivers / scsi / scsi_tgt_if.c

/*
 * SCSI target kernel/user interface functions
 *
 * Copyright (C) 2005 FUJITA Tomonori <tomof@acm.org>
 * Copyright (C) 2005 Mike Christie <michaelc@cs.wisc.edu>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 */
#include <linux/miscdevice.h>
#include <linux/gfp.h>
#include <linux/file.h>
#include <net/tcp.h>
#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_tgt.h>
#include <scsi/scsi_tgt_if.h>

#include <asm/cacheflush.h>

#include "scsi_tgt_priv.h"

#if TGT_RING_SIZE < PAGE_SIZE
#  define TGT_RING_SIZE PAGE_SIZE
#endif

#define TGT_RING_PAGES (TGT_RING_SIZE >> PAGE_SHIFT)
#define TGT_EVENT_PER_PAGE (PAGE_SIZE / sizeof(struct tgt_event))
#define TGT_MAX_EVENTS (TGT_EVENT_PER_PAGE * TGT_RING_PAGES)

struct tgt_ring {
	u32 tr_idx;
	unsigned long tr_pages[TGT_RING_PAGES];
	spinlock_t tr_lock;
};

/* tx_ring : kernel->user, rx_ring : user->kernel */
static struct tgt_ring tx_ring, rx_ring;
static DECLARE_WAIT_QUEUE_HEAD(tgt_poll_wait);

static inline void tgt_ring_idx_inc(struct tgt_ring *ring)
{
	if (ring->tr_idx == TGT_MAX_EVENTS - 1)
		ring->tr_idx = 0;
	else
		ring->tr_idx++;
}

static struct tgt_event *tgt_head_event(struct tgt_ring *ring, u32 idx)
{
	u32 pidx, off;

	pidx = idx / TGT_EVENT_PER_PAGE;
	off = idx % TGT_EVENT_PER_PAGE;

	return (struct tgt_event *)
		(ring->tr_pages[pidx] + sizeof(struct tgt_event) * off);
}

static int tgt_uspace_send_event(u32 type, struct tgt_event *p)
{
	struct tgt_event *ev;
	struct tgt_ring *ring = &tx_ring;
	unsigned long flags;
	int err = 0;

	spin_lock_irqsave(&ring->tr_lock, flags);

	ev = tgt_head_event(ring, ring->tr_idx);
	if (!ev->hdr.status)
		tgt_ring_idx_inc(ring);
	else
		err = -BUSY;

	spin_unlock_irqrestore(&ring->tr_lock, flags);

	if (err)
		return err;

	memcpy(ev, p, sizeof(*ev));
	ev->hdr.type = type;
	mb();
	ev->hdr.status = 1;

	flush_dcache_page(virt_to_page(ev));

	wake_up_interruptible(&tgt_poll_wait);

	return 0;
}

int scsi_tgt_uspace_send_cmd(struct scsi_cmnd *cmd, u64 itn_id,
			     struct scsi_lun *lun, u64 tag)
{
	struct Scsi_Host *shost = scsi_tgt_cmd_to_host(cmd);
	struct tgt_event ev;
	int err;

	memset(&ev, 0, sizeof(ev));
	ev.p.cmd_req.host_no = shost->host_no;
	ev.p.cmd_req.itn_id = itn_id;
	ev.p.cmd_req.data_len = scsi_bufflen(cmd);
	memcpy(ev.p.cmd_req.scb, cmd->cmnd, sizeof(ev.p.cmd_req.scb));
	memcpy(ev.p.cmd_req.lun, lun, sizeof(ev.p.cmd_req.lun));
	ev.p.cmd_req.attribute = cmd->tag;
	ev.p.cmd_req.tag = tag;

	dprintk("%p %d %u %x %llx\n", cmd, shost->host_no,
		ev.p.cmd_req.data_len, cmd->tag,
		(unsigned long long) ev.p.cmd_req.tag);

	err = tgt_uspace_send_event(TGT_KEVENT_CMD_REQ, &ev);
	if (err)
		eprintk("tx buf is full, could not send\n");

	return err;
}

int scsi_tgt_uspace_send_status(struct scsi_cmnd *cmd, u64 itn_id, u64 tag)
{
	struct Scsi_Host *shost = scsi_tgt_cmd_to_host(cmd);
	struct tgt_event ev;
	int err;

	memset(&ev, 0, sizeof(ev));
	ev.p.cmd_done.host_no = shost->host_no;
	ev.p.cmd_done.itn_id = itn_id;
	ev.p.cmd_done.tag = tag;
	ev.p.cmd_done.result = cmd->result;

	dprintk("%p %d %llu %u %x\n", cmd, shost->host_no,
		(unsigned long long) ev.p.cmd_req.tag,
		ev.p.cmd_req.data_len, cmd->tag);

	err = tgt_uspace_send_event(TGT_KEVENT_CMD_DONE, &ev);
	if (err)
		eprintk("tx buf is full, could not send\n");

	return err;
}

int scsi_tgt_uspace_send_tsk_mgmt(int host_no, u64 itn_id, int function,
				  u64 tag, struct scsi_lun *scsilun, void *data)
{
	struct tgt_event ev;
	int err;

	memset(&ev, 0, sizeof(ev));
	ev.p.tsk_mgmt_req.host_no = host_no;
	ev.p.tsk_mgmt_req.itn_id = itn_id;
	ev.p.tsk_mgmt_req.function = function;
	ev.p.tsk_mgmt_req.tag = tag;
	memcpy(ev.p.tsk_mgmt_req.lun, scsilun, sizeof(ev.p.tsk_mgmt_req.lun));
	ev.p.tsk_mgmt_req.mid = (u64) (unsigned long) data;

	dprintk("%d %x %llx %llx\n", host_no, function, (unsigned long long) tag,
		(unsigned long long) ev.p.tsk_mgmt_req.mid);

	err = tgt_uspace_send_event(TGT_KEVENT_TSK_MGMT_REQ, &ev);
	if (err)
		eprintk("tx buf is full, could not send\n");

	return err;
}

int scsi_tgt_uspace_send_it_nexus_request(int host_no, u64 itn_id,
					  int function, char *initiator_id)
{
	struct tgt_event ev;
	int err;

	memset(&ev, 0, sizeof(ev));
	ev.p.it_nexus_req.host_no = host_no;
	ev.p.it_nexus_req.function = function;
	ev.p.it_nexus_req.itn_id = itn_id;
	if (initiator_id)
		strncpy(ev.p.it_nexus_req.initiator_id, initiator_id,
			sizeof(ev.p.it_nexus_req.initiator_id));

	dprintk("%d %x %llx\n", host_no, function, (unsigned long long)itn_id);

	err = tgt_uspace_send_event(TGT_KEVENT_IT_NEXUS_REQ, &ev);
	if (err)
		eprintk("tx buf is full, could not send\n");

	return err;
}

static int event_recv_msg(struct tgt_event *ev)
{
	int err = 0;

	switch (ev->hdr.type) {
	case TGT_UEVENT_CMD_RSP:
		err = scsi_tgt_kspace_exec(ev->p.cmd_rsp.host_no,
					   ev->p.cmd_rsp.itn_id,
					   ev->p.cmd_rsp.result,
					   ev->p.cmd_rsp.tag,
					   ev->p.cmd_rsp.uaddr,
					   ev->p.cmd_rsp.len,
					   ev->p.cmd_rsp.sense_uaddr,
					   ev->p.cmd_rsp.sense_len,
					   ev->p.cmd_rsp.rw);
		break;
	case TGT_UEVENT_TSK_MGMT_RSP:
		err = scsi_tgt_kspace_tsk_mgmt(ev->p.tsk_mgmt_rsp.host_no,
					       ev->p.tsk_mgmt_rsp.itn_id,
					       ev->p.tsk_mgmt_rsp.mid,
					       ev->p.tsk_mgmt_rsp.result);
		break;
	case TGT_UEVENT_IT_NEXUS_RSP:
		err = scsi_tgt_kspace_it_nexus_rsp(ev->p.it_nexus_rsp.host_no,
						   ev->p.it_nexus_rsp.itn_id,
						   ev->p.it_nexus_rsp.result);
		break;
	default:
		eprintk("unknown type %d\n", ev->hdr.type);
		err = -EINVAL;
	}

	return err;
}

static ssize_t tgt_write(struct file *file, const char __user * buffer,
			 size_t count, loff_t * ppos)
{
	struct tgt_event *ev;
	struct tgt_ring *ring = &rx_ring;

	while (1) {
		ev = tgt_head_event(ring, ring->tr_idx);
		/* do we need this? */
		flush_dcache_page(virt_to_page(ev));

		if (!ev->hdr.status)
			break;

		tgt_ring_idx_inc(ring);
		event_recv_msg(ev);
		ev->hdr.status = 0;
	};

	return count;
}

static unsigned int tgt_poll(struct file * file, struct poll_table_struct *wait)
{
	struct tgt_event *ev;
	struct tgt_ring *ring = &tx_ring;
	unsigned long flags;
	unsigned int mask = 0;
	u32 idx;

	poll_wait(file, &tgt_poll_wait, wait);

	spin_lock_irqsave(&ring->tr_lock, flags);

	idx = ring->tr_idx ? ring->tr_idx - 1 : TGT_MAX_EVENTS - 1;
	ev = tgt_head_event(ring, idx);
	if (ev->hdr.status)
		mask |= POLLIN | POLLRDNORM;

	spin_unlock_irqrestore(&ring->tr_lock, flags);

	return mask;
}

static int uspace_ring_map(struct vm_area_struct *vma, unsigned long addr,
			   struct tgt_ring *ring)
{
	int i, err;

	for (i = 0; i < TGT_RING_PAGES; i++) {
		struct page *page = virt_to_page(ring->tr_pages[i]);
		err = vm_insert_page(vma, addr, page);
		if (err)
			return err;
		addr += PAGE_SIZE;
	}

	return 0;
}

static int tgt_mmap(struct file *filp, struct vm_area_struct *vma)
{
	unsigned long addr;
	int err;

	if (vma->vm_pgoff)
		return -EINVAL;

	if (vma->vm_end - vma->vm_start != TGT_RING_SIZE * 2) {
		eprintk("mmap size must be %lu, not %lu \n",
			TGT_RING_SIZE * 2, vma->vm_end - vma->vm_start);
		return -EINVAL;
	}

	addr = vma->vm_start;
	err = uspace_ring_map(vma, addr, &tx_ring);
	if (err)
		return err;
	err = uspace_ring_map(vma, addr + TGT_RING_SIZE, &rx_ring);

	return err;
}

static int tgt_open(struct inode *inode, struct file *file)
{
	tx_ring.tr_idx = rx_ring.tr_idx = 0;

	return 0;
}

static const struct file_operations tgt_fops = {
	.owner		= THIS_MODULE,
	.open		= tgt_open,
	.poll		= tgt_poll,
	.write		= tgt_write,
	.mmap		= tgt_mmap,
	.llseek		= noop_llseek,
};

static struct miscdevice tgt_miscdev = {
	.minor = MISC_DYNAMIC_MINOR,
	.name = "tgt",
	.fops = &tgt_fops,
};

static void tgt_ring_exit(struct tgt_ring *ring)
{
	int i;

	for (i = 0; i < TGT_RING_PAGES; i++)
		free_page(ring->tr_pages[i]);
}

static int tgt_ring_init(struct tgt_ring *ring)
{
	int i;

	spin_lock_init(&ring->tr_lock);

	for (i = 0; i < TGT_RING_PAGES; i++) {
		ring->tr_pages[i] = get_zeroed_page(GFP_KERNEL);
		if (!ring->tr_pages[i]) {
			eprintk("out of memory\n");
			return -ENOMEM;
		}
	}

	return 0;
}

void scsi_tgt_if_exit(void)
{
	tgt_ring_exit(&tx_ring);
	tgt_ring_exit(&rx_ring);
	misc_deregister(&tgt_miscdev);
}

int scsi_tgt_if_init(void)
{
	int err;

	err = tgt_ring_init(&tx_ring);
	if (err)
		return err;

	err = tgt_ring_init(&rx_ring);
	if (err)
		goto free_tx_ring;

	err = misc_register(&tgt_miscdev);
	if (err)
		goto free_rx_ring;

	return 0;
free_rx_ring:
	tgt_ring_exit(&rx_ring);
free_tx_ring:
	tgt_ring_exit(&tx_ring);

	return err;
}
Commit	Line	Data
97f78759 FT	1	/*
	2	* SCSI target kernel/user interface functions
	3	*
	4	* Copyright (C) 2005 FUJITA Tomonori <tomof@acm.org>
	5	* Copyright (C) 2005 Mike Christie <michaelc@cs.wisc.edu>
	6	*
	7	* This program is free software; you can redistribute it and/or
	8	* modify it under the terms of the GNU General Public License as
	9	* published by the Free Software Foundation; either version 2 of the
	10	* License, or (at your option) any later version.
	11	*
	12	* This program is distributed in the hope that it will be useful, but
	13	* WITHOUT ANY WARRANTY; without even the implied warranty of
	14	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	15	* General Public License for more details.
	16	*
	17	* You should have received a copy of the GNU General Public License
	18	* along with this program; if not, write to the Free Software
	19	* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
	20	* 02110-1301 USA
	21	*/
	22	#include <linux/miscdevice.h>
5a0e3ad6	23	#include <linux/gfp.h>
97f78759 FT	24	#include <linux/file.h>
	25	#include <net/tcp.h>
	26	#include <scsi/scsi.h>
	27	#include <scsi/scsi_cmnd.h>
	28	#include <scsi/scsi_device.h>
	29	#include <scsi/scsi_host.h>
	30	#include <scsi/scsi_tgt.h>
	31	#include <scsi/scsi_tgt_if.h>
	32
e42ebefe AM	33	#include <asm/cacheflush.h>
e42ebefe AM	34
97f78759 FT	35	#include "scsi_tgt_priv.h"
97f78759 FT	36
930e99bd FT	37	#if TGT_RING_SIZE < PAGE_SIZE
	38	# define TGT_RING_SIZE PAGE_SIZE
	39	#endif
	40
	41	#define TGT_RING_PAGES (TGT_RING_SIZE >> PAGE_SHIFT)
	42	#define TGT_EVENT_PER_PAGE (PAGE_SIZE / sizeof(struct tgt_event))
	43	#define TGT_MAX_EVENTS (TGT_EVENT_PER_PAGE * TGT_RING_PAGES)
	44
97f78759 FT	45	struct tgt_ring {
	46	u32 tr_idx;
	47	unsigned long tr_pages[TGT_RING_PAGES];
	48	spinlock_t tr_lock;
	49	};
	50
	51	/* tx_ring : kernel->user, rx_ring : user->kernel */
	52	static struct tgt_ring tx_ring, rx_ring;
	53	static DECLARE_WAIT_QUEUE_HEAD(tgt_poll_wait);
	54
	55	static inline void tgt_ring_idx_inc(struct tgt_ring *ring)
	56	{
	57	if (ring->tr_idx == TGT_MAX_EVENTS - 1)
	58	ring->tr_idx = 0;
	59	else
	60	ring->tr_idx++;
	61	}
	62
	63	static struct tgt_event tgt_head_event(struct tgt_ring ring, u32 idx)
	64	{
	65	u32 pidx, off;
	66
	67	pidx = idx / TGT_EVENT_PER_PAGE;
	68	off = idx % TGT_EVENT_PER_PAGE;
	69
	70	return (struct tgt_event *)
	71	(ring->tr_pages[pidx] + sizeof(struct tgt_event) * off);
	72	}
	73
	74	static int tgt_uspace_send_event(u32 type, struct tgt_event *p)
	75	{
	76	struct tgt_event *ev;
	77	struct tgt_ring *ring = &tx_ring;
	78	unsigned long flags;
	79	int err = 0;
	80
	81	spin_lock_irqsave(&ring->tr_lock, flags);
	82
	83	ev = tgt_head_event(ring, ring->tr_idx);
	84	if (!ev->hdr.status)
	85	tgt_ring_idx_inc(ring);
	86	else
	87	err = -BUSY;
	88
	89	spin_unlock_irqrestore(&ring->tr_lock, flags);
	90
	91	if (err)
	92	return err;
	93
	94	memcpy(ev, p, sizeof(*ev));
	95	ev->hdr.type = type;
	96	mb();
	97	ev->hdr.status = 1;
	98
	99	flush_dcache_page(virt_to_page(ev));
	100
	101	wake_up_interruptible(&tgt_poll_wait);
	102
	103	return 0;
	104	}
	105
2c47f9ef FT	106	int scsi_tgt_uspace_send_cmd(struct scsi_cmnd *cmd, u64 itn_id,
2c47f9ef FT	107	struct scsi_lun *lun, u64 tag)
97f78759 FT	108	{
	109	struct Scsi_Host *shost = scsi_tgt_cmd_to_host(cmd);
	110	struct tgt_event ev;
	111	int err;
	112
	113	memset(&ev, 0, sizeof(ev));
	114	ev.p.cmd_req.host_no = shost->host_no;
2c47f9ef	115	ev.p.cmd_req.itn_id = itn_id;
f10ab66f	116	ev.p.cmd_req.data_len = scsi_bufflen(cmd);
97f78759 FT	117	memcpy(ev.p.cmd_req.scb, cmd->cmnd, sizeof(ev.p.cmd_req.scb));
	118	memcpy(ev.p.cmd_req.lun, lun, sizeof(ev.p.cmd_req.lun));
	119	ev.p.cmd_req.attribute = cmd->tag;
	120	ev.p.cmd_req.tag = tag;
	121
	122	dprintk("%p %d %u %x %llx\n", cmd, shost->host_no,
	123	ev.p.cmd_req.data_len, cmd->tag,
	124	(unsigned long long) ev.p.cmd_req.tag);
	125
	126	err = tgt_uspace_send_event(TGT_KEVENT_CMD_REQ, &ev);
	127	if (err)
	128	eprintk("tx buf is full, could not send\n");
	129
	130	return err;
	131	}
	132
2c47f9ef	133	int scsi_tgt_uspace_send_status(struct scsi_cmnd *cmd, u64 itn_id, u64 tag)
97f78759 FT	134	{
	135	struct Scsi_Host *shost = scsi_tgt_cmd_to_host(cmd);
	136	struct tgt_event ev;
	137	int err;
	138
	139	memset(&ev, 0, sizeof(ev));
	140	ev.p.cmd_done.host_no = shost->host_no;
2c47f9ef	141	ev.p.cmd_done.itn_id = itn_id;
97f78759 FT	142	ev.p.cmd_done.tag = tag;
	143	ev.p.cmd_done.result = cmd->result;
	144
	145	dprintk("%p %d %llu %u %x\n", cmd, shost->host_no,
	146	(unsigned long long) ev.p.cmd_req.tag,
	147	ev.p.cmd_req.data_len, cmd->tag);
	148
	149	err = tgt_uspace_send_event(TGT_KEVENT_CMD_DONE, &ev);
	150	if (err)
	151	eprintk("tx buf is full, could not send\n");
	152
	153	return err;
	154	}
	155
2c47f9ef FT	156	int scsi_tgt_uspace_send_tsk_mgmt(int host_no, u64 itn_id, int function,
2c47f9ef FT	157	u64 tag, struct scsi_lun scsilun, void data)
97f78759 FT	158	{
	159	struct tgt_event ev;
	160	int err;
	161
	162	memset(&ev, 0, sizeof(ev));
	163	ev.p.tsk_mgmt_req.host_no = host_no;
2c47f9ef	164	ev.p.tsk_mgmt_req.itn_id = itn_id;
97f78759 FT	165	ev.p.tsk_mgmt_req.function = function;
	166	ev.p.tsk_mgmt_req.tag = tag;
	167	memcpy(ev.p.tsk_mgmt_req.lun, scsilun, sizeof(ev.p.tsk_mgmt_req.lun));
	168	ev.p.tsk_mgmt_req.mid = (u64) (unsigned long) data;
	169
	170	dprintk("%d %x %llx %llx\n", host_no, function, (unsigned long long) tag,
	171	(unsigned long long) ev.p.tsk_mgmt_req.mid);
	172
	173	err = tgt_uspace_send_event(TGT_KEVENT_TSK_MGMT_REQ, &ev);
	174	if (err)
	175	eprintk("tx buf is full, could not send\n");
	176
	177	return err;
	178	}
	179
2c47f9ef FT	180	int scsi_tgt_uspace_send_it_nexus_request(int host_no, u64 itn_id,
	181	int function, char *initiator_id)
	182	{
	183	struct tgt_event ev;
	184	int err;
	185
	186	memset(&ev, 0, sizeof(ev));
	187	ev.p.it_nexus_req.host_no = host_no;
	188	ev.p.it_nexus_req.function = function;
	189	ev.p.it_nexus_req.itn_id = itn_id;
	190	if (initiator_id)
	191	strncpy(ev.p.it_nexus_req.initiator_id, initiator_id,
	192	sizeof(ev.p.it_nexus_req.initiator_id));
	193
	194	dprintk("%d %x %llx\n", host_no, function, (unsigned long long)itn_id);
	195
	196	err = tgt_uspace_send_event(TGT_KEVENT_IT_NEXUS_REQ, &ev);
	197	if (err)
	198	eprintk("tx buf is full, could not send\n");
	199
	200	return err;
	201	}
	202
97f78759 FT	203	static int event_recv_msg(struct tgt_event *ev)
	204	{
	205	int err = 0;
	206
	207	switch (ev->hdr.type) {
	208	case TGT_UEVENT_CMD_RSP:
	209	err = scsi_tgt_kspace_exec(ev->p.cmd_rsp.host_no,
2c47f9ef	210	ev->p.cmd_rsp.itn_id,
97f78759	211	ev->p.cmd_rsp.result,
bc7e380a	212	ev->p.cmd_rsp.tag,
97f78759	213	ev->p.cmd_rsp.uaddr,
bc7e380a FT	214	ev->p.cmd_rsp.len,
	215	ev->p.cmd_rsp.sense_uaddr,
	216	ev->p.cmd_rsp.sense_len,
97f78759 FT	217	ev->p.cmd_rsp.rw);
	218	break;
	219	case TGT_UEVENT_TSK_MGMT_RSP:
	220	err = scsi_tgt_kspace_tsk_mgmt(ev->p.tsk_mgmt_rsp.host_no,
2c47f9ef	221	ev->p.tsk_mgmt_rsp.itn_id,
97f78759 FT	222	ev->p.tsk_mgmt_rsp.mid,
	223	ev->p.tsk_mgmt_rsp.result);
	224	break;
2c47f9ef FT	225	case TGT_UEVENT_IT_NEXUS_RSP:
	226	err = scsi_tgt_kspace_it_nexus_rsp(ev->p.it_nexus_rsp.host_no,
	227	ev->p.it_nexus_rsp.itn_id,
	228	ev->p.it_nexus_rsp.result);
	229	break;
97f78759 FT	230	default:
	231	eprintk("unknown type %d\n", ev->hdr.type);
	232	err = -EINVAL;
	233	}
	234
	235	return err;
	236	}
	237
	238	static ssize_t tgt_write(struct file file, const char __user buffer,
	239	size_t count, loff_t * ppos)
	240	{
	241	struct tgt_event *ev;
	242	struct tgt_ring *ring = &rx_ring;
	243
	244	while (1) {
	245	ev = tgt_head_event(ring, ring->tr_idx);
	246	/* do we need this? */
	247	flush_dcache_page(virt_to_page(ev));
	248
	249	if (!ev->hdr.status)
	250	break;
	251
	252	tgt_ring_idx_inc(ring);
	253	event_recv_msg(ev);
	254	ev->hdr.status = 0;
	255	};
	256
	257	return count;
	258	}
	259
	260	static unsigned int tgt_poll(struct file * file, struct poll_table_struct *wait)
	261	{
	262	struct tgt_event *ev;
	263	struct tgt_ring *ring = &tx_ring;
	264	unsigned long flags;
	265	unsigned int mask = 0;
	266	u32 idx;
	267
	268	poll_wait(file, &tgt_poll_wait, wait);
	269
	270	spin_lock_irqsave(&ring->tr_lock, flags);
	271
	272	idx = ring->tr_idx ? ring->tr_idx - 1 : TGT_MAX_EVENTS - 1;
	273	ev = tgt_head_event(ring, idx);
	274	if (ev->hdr.status)
	275	mask \|= POLLIN \| POLLRDNORM;
	276
	277	spin_unlock_irqrestore(&ring->tr_lock, flags);
	278
	279	return mask;
	280	}
	281
	282	static int uspace_ring_map(struct vm_area_struct *vma, unsigned long addr,
	283	struct tgt_ring *ring)
	284	{
	285	int i, err;
	286
	287	for (i = 0; i < TGT_RING_PAGES; i++) {
	288	struct page *page = virt_to_page(ring->tr_pages[i]);
	289	err = vm_insert_page(vma, addr, page);
	290	if (err)
	291	return err;
	292	addr += PAGE_SIZE;
	293	}
294
295	return 0;
296	}
297
298	static int tgt_mmap(struct file filp, struct vm_area_struct vma)
299	{
300	unsigned long addr;
301	int err;
302
303	if (vma->vm_pgoff)
304	return -EINVAL;
305
306	if (vma->vm_end - vma->vm_start != TGT_RING_SIZE * 2) {
307	eprintk("mmap size must be %lu, not %lu \n",
308	TGT_RING_SIZE * 2, vma->vm_end - vma->vm_start);
309	return -EINVAL;
310	}
311
312	addr = vma->vm_start;
313	err = uspace_ring_map(vma, addr, &tx_ring);
314	if (err)
315	return err;
316	err = uspace_ring_map(vma, addr + TGT_RING_SIZE, &rx_ring);
317
318	return err;
319	}
320
321	static int tgt_open(struct inode inode, struct file file)
322	{
323	tx_ring.tr_idx = rx_ring.tr_idx = 0;
324
325	return 0;
326	}
327
00977a59	328	static const struct file_operations tgt_fops = {
97f78759 FT	329	.owner = THIS_MODULE,
	330	.open = tgt_open,
	331	.poll = tgt_poll,
	332	.write = tgt_write,
	333	.mmap = tgt_mmap,
6038f373	334	.llseek = noop_llseek,
97f78759 FT	335	};
	336
	337	static struct miscdevice tgt_miscdev = {
	338	.minor = MISC_DYNAMIC_MINOR,
	339	.name = "tgt",
	340	.fops = &tgt_fops,
	341	};
	342
	343	static void tgt_ring_exit(struct tgt_ring *ring)
	344	{
	345	int i;
	346
	347	for (i = 0; i < TGT_RING_PAGES; i++)
	348	free_page(ring->tr_pages[i]);
	349	}
	350
	351	static int tgt_ring_init(struct tgt_ring *ring)
	352	{
	353	int i;
	354
	355	spin_lock_init(&ring->tr_lock);
	356
	357	for (i = 0; i < TGT_RING_PAGES; i++) {
	358	ring->tr_pages[i] = get_zeroed_page(GFP_KERNEL);
	359	if (!ring->tr_pages[i]) {
	360	eprintk("out of memory\n");
	361	return -ENOMEM;
	362	}
	363	}
	364
	365	return 0;
	366	}
	367
	368	void scsi_tgt_if_exit(void)
	369	{
	370	tgt_ring_exit(&tx_ring);
	371	tgt_ring_exit(&rx_ring);
	372	misc_deregister(&tgt_miscdev);
	373	}
	374
	375	int scsi_tgt_if_init(void)
	376	{
	377	int err;
	378
	379	err = tgt_ring_init(&tx_ring);
	380	if (err)
	381	return err;
	382
	383	err = tgt_ring_init(&rx_ring);
	384	if (err)
	385	goto free_tx_ring;
	386
	387	err = misc_register(&tgt_miscdev);
	388	if (err)
	389	goto free_rx_ring;
	390
	391	return 0;
	392	free_rx_ring:
	393	tgt_ring_exit(&rx_ring);
	394	free_tx_ring:
	395	tgt_ring_exit(&tx_ring);
	396
	397	return err;
	398	}