[GitHub/mt8127/android_kernel_alcatel_ttab.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/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,
};

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>
	23	#include <linux/file.h>
	24	#include <net/tcp.h>
	25	#include <scsi/scsi.h>
	26	#include <scsi/scsi_cmnd.h>
	27	#include <scsi/scsi_device.h>
	28	#include <scsi/scsi_host.h>
	29	#include <scsi/scsi_tgt.h>
	30	#include <scsi/scsi_tgt_if.h>
	31
e42ebefe AM	32	#include <asm/cacheflush.h>
e42ebefe AM	33
97f78759 FT	34	#include "scsi_tgt_priv.h"
97f78759 FT	35
930e99bd FT	36	#if TGT_RING_SIZE < PAGE_SIZE
	37	# define TGT_RING_SIZE PAGE_SIZE
	38	#endif
	39
	40	#define TGT_RING_PAGES (TGT_RING_SIZE >> PAGE_SHIFT)
	41	#define TGT_EVENT_PER_PAGE (PAGE_SIZE / sizeof(struct tgt_event))
	42	#define TGT_MAX_EVENTS (TGT_EVENT_PER_PAGE * TGT_RING_PAGES)
	43
97f78759 FT	44	struct tgt_ring {
	45	u32 tr_idx;
	46	unsigned long tr_pages[TGT_RING_PAGES];
	47	spinlock_t tr_lock;
	48	};
	49
	50	/* tx_ring : kernel->user, rx_ring : user->kernel */
	51	static struct tgt_ring tx_ring, rx_ring;
	52	static DECLARE_WAIT_QUEUE_HEAD(tgt_poll_wait);
	53
	54	static inline void tgt_ring_idx_inc(struct tgt_ring *ring)
	55	{
	56	if (ring->tr_idx == TGT_MAX_EVENTS - 1)
	57	ring->tr_idx = 0;
	58	else
	59	ring->tr_idx++;
	60	}
	61
	62	static struct tgt_event tgt_head_event(struct tgt_ring ring, u32 idx)
	63	{
	64	u32 pidx, off;
	65
	66	pidx = idx / TGT_EVENT_PER_PAGE;
	67	off = idx % TGT_EVENT_PER_PAGE;
	68
	69	return (struct tgt_event *)
	70	(ring->tr_pages[pidx] + sizeof(struct tgt_event) * off);
	71	}
	72
	73	static int tgt_uspace_send_event(u32 type, struct tgt_event *p)
	74	{
	75	struct tgt_event *ev;
	76	struct tgt_ring *ring = &tx_ring;
	77	unsigned long flags;
	78	int err = 0;
	79
	80	spin_lock_irqsave(&ring->tr_lock, flags);
	81
	82	ev = tgt_head_event(ring, ring->tr_idx);
	83	if (!ev->hdr.status)
	84	tgt_ring_idx_inc(ring);
	85	else
	86	err = -BUSY;
	87
	88	spin_unlock_irqrestore(&ring->tr_lock, flags);
	89
	90	if (err)
	91	return err;
	92
	93	memcpy(ev, p, sizeof(*ev));
	94	ev->hdr.type = type;
	95	mb();
	96	ev->hdr.status = 1;
	97
	98	flush_dcache_page(virt_to_page(ev));
	99
	100	wake_up_interruptible(&tgt_poll_wait);
	101
	102	return 0;
	103	}
	104
2c47f9ef FT	105	int scsi_tgt_uspace_send_cmd(struct scsi_cmnd *cmd, u64 itn_id,
2c47f9ef FT	106	struct scsi_lun *lun, u64 tag)
97f78759 FT	107	{
	108	struct Scsi_Host *shost = scsi_tgt_cmd_to_host(cmd);
	109	struct tgt_event ev;
	110	int err;
	111
	112	memset(&ev, 0, sizeof(ev));
	113	ev.p.cmd_req.host_no = shost->host_no;
2c47f9ef	114	ev.p.cmd_req.itn_id = itn_id;
f10ab66f	115	ev.p.cmd_req.data_len = scsi_bufflen(cmd);
97f78759 FT	116	memcpy(ev.p.cmd_req.scb, cmd->cmnd, sizeof(ev.p.cmd_req.scb));
	117	memcpy(ev.p.cmd_req.lun, lun, sizeof(ev.p.cmd_req.lun));
	118	ev.p.cmd_req.attribute = cmd->tag;
	119	ev.p.cmd_req.tag = tag;
	120
	121	dprintk("%p %d %u %x %llx\n", cmd, shost->host_no,
	122	ev.p.cmd_req.data_len, cmd->tag,
	123	(unsigned long long) ev.p.cmd_req.tag);
	124
	125	err = tgt_uspace_send_event(TGT_KEVENT_CMD_REQ, &ev);
	126	if (err)
	127	eprintk("tx buf is full, could not send\n");
	128
	129	return err;
	130	}
	131
2c47f9ef	132	int scsi_tgt_uspace_send_status(struct scsi_cmnd *cmd, u64 itn_id, u64 tag)
97f78759 FT	133	{
	134	struct Scsi_Host *shost = scsi_tgt_cmd_to_host(cmd);
	135	struct tgt_event ev;
	136	int err;
	137
	138	memset(&ev, 0, sizeof(ev));
	139	ev.p.cmd_done.host_no = shost->host_no;
2c47f9ef	140	ev.p.cmd_done.itn_id = itn_id;
97f78759 FT	141	ev.p.cmd_done.tag = tag;
	142	ev.p.cmd_done.result = cmd->result;
	143
	144	dprintk("%p %d %llu %u %x\n", cmd, shost->host_no,
	145	(unsigned long long) ev.p.cmd_req.tag,
	146	ev.p.cmd_req.data_len, cmd->tag);
	147
	148	err = tgt_uspace_send_event(TGT_KEVENT_CMD_DONE, &ev);
	149	if (err)
	150	eprintk("tx buf is full, could not send\n");
	151
	152	return err;
	153	}
	154
2c47f9ef FT	155	int scsi_tgt_uspace_send_tsk_mgmt(int host_no, u64 itn_id, int function,
2c47f9ef FT	156	u64 tag, struct scsi_lun scsilun, void data)
97f78759 FT	157	{
	158	struct tgt_event ev;
	159	int err;
	160
	161	memset(&ev, 0, sizeof(ev));
	162	ev.p.tsk_mgmt_req.host_no = host_no;
2c47f9ef	163	ev.p.tsk_mgmt_req.itn_id = itn_id;
97f78759 FT	164	ev.p.tsk_mgmt_req.function = function;
	165	ev.p.tsk_mgmt_req.tag = tag;
	166	memcpy(ev.p.tsk_mgmt_req.lun, scsilun, sizeof(ev.p.tsk_mgmt_req.lun));
	167	ev.p.tsk_mgmt_req.mid = (u64) (unsigned long) data;
	168
	169	dprintk("%d %x %llx %llx\n", host_no, function, (unsigned long long) tag,
	170	(unsigned long long) ev.p.tsk_mgmt_req.mid);
	171
	172	err = tgt_uspace_send_event(TGT_KEVENT_TSK_MGMT_REQ, &ev);
	173	if (err)
	174	eprintk("tx buf is full, could not send\n");
	175
	176	return err;
	177	}
	178
2c47f9ef FT	179	int scsi_tgt_uspace_send_it_nexus_request(int host_no, u64 itn_id,
	180	int function, char *initiator_id)
	181	{
	182	struct tgt_event ev;
	183	int err;
	184
	185	memset(&ev, 0, sizeof(ev));
	186	ev.p.it_nexus_req.host_no = host_no;
	187	ev.p.it_nexus_req.function = function;
	188	ev.p.it_nexus_req.itn_id = itn_id;
	189	if (initiator_id)
	190	strncpy(ev.p.it_nexus_req.initiator_id, initiator_id,
	191	sizeof(ev.p.it_nexus_req.initiator_id));
	192
	193	dprintk("%d %x %llx\n", host_no, function, (unsigned long long)itn_id);
	194
	195	err = tgt_uspace_send_event(TGT_KEVENT_IT_NEXUS_REQ, &ev);
	196	if (err)
	197	eprintk("tx buf is full, could not send\n");
	198
	199	return err;
	200	}
	201
97f78759 FT	202	static int event_recv_msg(struct tgt_event *ev)
	203	{
	204	int err = 0;
	205
	206	switch (ev->hdr.type) {
	207	case TGT_UEVENT_CMD_RSP:
	208	err = scsi_tgt_kspace_exec(ev->p.cmd_rsp.host_no,
2c47f9ef	209	ev->p.cmd_rsp.itn_id,
97f78759	210	ev->p.cmd_rsp.result,
bc7e380a	211	ev->p.cmd_rsp.tag,
97f78759	212	ev->p.cmd_rsp.uaddr,
bc7e380a FT	213	ev->p.cmd_rsp.len,
	214	ev->p.cmd_rsp.sense_uaddr,
	215	ev->p.cmd_rsp.sense_len,
97f78759 FT	216	ev->p.cmd_rsp.rw);
	217	break;
	218	case TGT_UEVENT_TSK_MGMT_RSP:
	219	err = scsi_tgt_kspace_tsk_mgmt(ev->p.tsk_mgmt_rsp.host_no,
2c47f9ef	220	ev->p.tsk_mgmt_rsp.itn_id,
97f78759 FT	221	ev->p.tsk_mgmt_rsp.mid,
	222	ev->p.tsk_mgmt_rsp.result);
	223	break;
2c47f9ef FT	224	case TGT_UEVENT_IT_NEXUS_RSP:
	225	err = scsi_tgt_kspace_it_nexus_rsp(ev->p.it_nexus_rsp.host_no,
	226	ev->p.it_nexus_rsp.itn_id,
	227	ev->p.it_nexus_rsp.result);
	228	break;
97f78759 FT	229	default:
	230	eprintk("unknown type %d\n", ev->hdr.type);
	231	err = -EINVAL;
	232	}
	233
	234	return err;
	235	}
	236
	237	static ssize_t tgt_write(struct file file, const char __user buffer,
	238	size_t count, loff_t * ppos)
	239	{
	240	struct tgt_event *ev;
	241	struct tgt_ring *ring = &rx_ring;
	242
	243	while (1) {
	244	ev = tgt_head_event(ring, ring->tr_idx);
	245	/* do we need this? */
	246	flush_dcache_page(virt_to_page(ev));
	247
	248	if (!ev->hdr.status)
	249	break;
	250
	251	tgt_ring_idx_inc(ring);
	252	event_recv_msg(ev);
	253	ev->hdr.status = 0;
	254	};
	255
	256	return count;
	257	}
	258
	259	static unsigned int tgt_poll(struct file * file, struct poll_table_struct *wait)
	260	{
	261	struct tgt_event *ev;
	262	struct tgt_ring *ring = &tx_ring;
	263	unsigned long flags;
	264	unsigned int mask = 0;
	265	u32 idx;
	266
	267	poll_wait(file, &tgt_poll_wait, wait);
	268
	269	spin_lock_irqsave(&ring->tr_lock, flags);
	270
	271	idx = ring->tr_idx ? ring->tr_idx - 1 : TGT_MAX_EVENTS - 1;
	272	ev = tgt_head_event(ring, idx);
	273	if (ev->hdr.status)
	274	mask \|= POLLIN \| POLLRDNORM;
	275
	276	spin_unlock_irqrestore(&ring->tr_lock, flags);
	277
	278	return mask;
	279	}
	280
	281	static int uspace_ring_map(struct vm_area_struct *vma, unsigned long addr,
	282	struct tgt_ring *ring)
	283	{
	284	int i, err;
	285
	286	for (i = 0; i < TGT_RING_PAGES; i++) {
	287	struct page *page = virt_to_page(ring->tr_pages[i]);
	288	err = vm_insert_page(vma, addr, page);
	289	if (err)
	290	return err;
	291	addr += PAGE_SIZE;
	292	}
293
294	return 0;
295	}
296
297	static int tgt_mmap(struct file filp, struct vm_area_struct vma)
298	{
299	unsigned long addr;
300	int err;
301
302	if (vma->vm_pgoff)
303	return -EINVAL;
304
305	if (vma->vm_end - vma->vm_start != TGT_RING_SIZE * 2) {
306	eprintk("mmap size must be %lu, not %lu \n",
307	TGT_RING_SIZE * 2, vma->vm_end - vma->vm_start);
308	return -EINVAL;
309	}
310
311	addr = vma->vm_start;
312	err = uspace_ring_map(vma, addr, &tx_ring);
313	if (err)
314	return err;
315	err = uspace_ring_map(vma, addr + TGT_RING_SIZE, &rx_ring);
316
317	return err;
318	}
319
320	static int tgt_open(struct inode inode, struct file file)
321	{
322	tx_ring.tr_idx = rx_ring.tr_idx = 0;
323
324	return 0;
325	}
326
00977a59	327	static const struct file_operations tgt_fops = {
97f78759 FT	328	.owner = THIS_MODULE,
	329	.open = tgt_open,
	330	.poll = tgt_poll,
	331	.write = tgt_write,
	332	.mmap = tgt_mmap,
	333	};
	334
	335	static struct miscdevice tgt_miscdev = {
	336	.minor = MISC_DYNAMIC_MINOR,
	337	.name = "tgt",
	338	.fops = &tgt_fops,
	339	};
	340
	341	static void tgt_ring_exit(struct tgt_ring *ring)
	342	{
	343	int i;
	344
	345	for (i = 0; i < TGT_RING_PAGES; i++)
	346	free_page(ring->tr_pages[i]);
	347	}
	348
	349	static int tgt_ring_init(struct tgt_ring *ring)
	350	{
	351	int i;
	352
	353	spin_lock_init(&ring->tr_lock);
	354
	355	for (i = 0; i < TGT_RING_PAGES; i++) {
	356	ring->tr_pages[i] = get_zeroed_page(GFP_KERNEL);
	357	if (!ring->tr_pages[i]) {
	358	eprintk("out of memory\n");
	359	return -ENOMEM;
	360	}
	361	}
	362
	363	return 0;
	364	}
	365
	366	void scsi_tgt_if_exit(void)
	367	{
	368	tgt_ring_exit(&tx_ring);
	369	tgt_ring_exit(&rx_ring);
	370	misc_deregister(&tgt_miscdev);
	371	}
	372
	373	int scsi_tgt_if_init(void)
	374	{
	375	int err;
	376
	377	err = tgt_ring_init(&tx_ring);
	378	if (err)
	379	return err;
	380
	381	err = tgt_ring_init(&rx_ring);
	382	if (err)
	383	goto free_tx_ring;
	384
	385	err = misc_register(&tgt_miscdev);
	386	if (err)
	387	goto free_rx_ring;
	388
	389	return 0;
	390	free_rx_ring:
	391	tgt_ring_exit(&rx_ring);
392	free_tx_ring:
393	tgt_ring_exit(&tx_ring);
394
395	return err;
396	}