[net-next-2.6.git] / drivers / block / aoe / aoechr.c

/* Copyright (c) 2007 Coraid, Inc.  See COPYING for GPL terms. */
/*
 * aoechr.c
 * AoE character device driver
 */

#include <linux/hdreg.h>
#include <linux/blkdev.h>
#include <linux/delay.h>
#include <linux/smp_lock.h>
#include "aoe.h"

enum {
	//MINOR_STAT = 1, (moved to sysfs)
	MINOR_ERR = 2,
	MINOR_DISCOVER,
	MINOR_INTERFACES,
	MINOR_REVALIDATE,
	MINOR_FLUSH,
	MSGSZ = 2048,
	NMSG = 100,		/* message backlog to retain */
};

struct aoe_chardev {
	ulong minor;
	char name[32];
};

enum { EMFL_VALID = 1 };

struct ErrMsg {
	short flags;
	short len;
	char *msg;
};

static struct ErrMsg emsgs[NMSG];
static int emsgs_head_idx, emsgs_tail_idx;
static struct semaphore emsgs_sema;
static spinlock_t emsgs_lock;
static int nblocked_emsgs_readers;
static struct class *aoe_class;
static struct aoe_chardev chardevs[] = {
	{ MINOR_ERR, "err" },
	{ MINOR_DISCOVER, "discover" },
	{ MINOR_INTERFACES, "interfaces" },
	{ MINOR_REVALIDATE, "revalidate" },
	{ MINOR_FLUSH, "flush" },
};

static int
discover(void)
{
	aoecmd_cfg(0xffff, 0xff);
	return 0;
}

static int
interfaces(const char __user *str, size_t size)
{
	if (set_aoe_iflist(str, size)) {
		printk(KERN_ERR
			"aoe: could not set interface list: too many interfaces\n");
		return -EINVAL;
	}
	return 0;
}

static int
revalidate(const char __user *str, size_t size)
{
	int major, minor, n;
	ulong flags;
	struct aoedev *d;
	struct sk_buff *skb;
	char buf[16];

	if (size >= sizeof buf)
		return -EINVAL;
	buf[sizeof buf - 1] = '\0';
	if (copy_from_user(buf, str, size))
		return -EFAULT;

	/* should be e%d.%d format */
	n = sscanf(buf, "e%d.%d", &major, &minor);
	if (n != 2) {
		printk(KERN_ERR "aoe: invalid device specification\n");
		return -EINVAL;
	}
	d = aoedev_by_aoeaddr(major, minor);
	if (!d)
		return -EINVAL;
	spin_lock_irqsave(&d->lock, flags);
	aoecmd_cleanslate(d);
loop:
	skb = aoecmd_ata_id(d);
	spin_unlock_irqrestore(&d->lock, flags);
	/* try again if we are able to sleep a bit,
	 * otherwise give up this revalidation
	 */
	if (!skb && !msleep_interruptible(200)) {
		spin_lock_irqsave(&d->lock, flags);
		goto loop;
	}
	aoenet_xmit(skb);
	aoecmd_cfg(major, minor);
	return 0;
}

void
aoechr_error(char *msg)
{
	struct ErrMsg *em;
	char *mp;
	ulong flags, n;

	n = strlen(msg);

	spin_lock_irqsave(&emsgs_lock, flags);

	em = emsgs + emsgs_tail_idx;
	if ((em->flags & EMFL_VALID)) {
bail:		spin_unlock_irqrestore(&emsgs_lock, flags);
		return;
	}

	mp = kmalloc(n, GFP_ATOMIC);
	if (mp == NULL) {
		printk(KERN_ERR "aoe: allocation failure, len=%ld\n", n);
		goto bail;
	}

	memcpy(mp, msg, n);
	em->msg = mp;
	em->flags |= EMFL_VALID;
	em->len = n;

	emsgs_tail_idx++;
	emsgs_tail_idx %= ARRAY_SIZE(emsgs);

	spin_unlock_irqrestore(&emsgs_lock, flags);

	if (nblocked_emsgs_readers)
		up(&emsgs_sema);
}

static ssize_t
aoechr_write(struct file *filp, const char __user *buf, size_t cnt, loff_t *offp)
{
	int ret = -EINVAL;

	switch ((unsigned long) filp->private_data) {
	default:
		printk(KERN_INFO "aoe: can't write to that file.\n");
		break;
	case MINOR_DISCOVER:
		ret = discover();
		break;
	case MINOR_INTERFACES:
		ret = interfaces(buf, cnt);
		break;
	case MINOR_REVALIDATE:
		ret = revalidate(buf, cnt);
		break;
	case MINOR_FLUSH:
		ret = aoedev_flush(buf, cnt);
	}
	if (ret == 0)
		ret = cnt;
	return ret;
}

static int
aoechr_open(struct inode *inode, struct file *filp)
{
	int n, i;

	lock_kernel();
	n = iminor(inode);
	filp->private_data = (void *) (unsigned long) n;

	for (i = 0; i < ARRAY_SIZE(chardevs); ++i)
		if (chardevs[i].minor == n) {
			unlock_kernel();
			return 0;
		}
	unlock_kernel();
	return -EINVAL;
}

static int
aoechr_rel(struct inode *inode, struct file *filp)
{
	return 0;
}

static ssize_t
aoechr_read(struct file *filp, char __user *buf, size_t cnt, loff_t *off)
{
	unsigned long n;
	char *mp;
	struct ErrMsg *em;
	ssize_t len;
	ulong flags;

	n = (unsigned long) filp->private_data;
	if (n != MINOR_ERR)
		return -EFAULT;

	spin_lock_irqsave(&emsgs_lock, flags);

	for (;;) {
		em = emsgs + emsgs_head_idx;
		if ((em->flags & EMFL_VALID) != 0)
			break;
		if (filp->f_flags & O_NDELAY) {
			spin_unlock_irqrestore(&emsgs_lock, flags);
			return -EAGAIN;
		}
		nblocked_emsgs_readers++;

		spin_unlock_irqrestore(&emsgs_lock, flags);

		n = down_interruptible(&emsgs_sema);

		spin_lock_irqsave(&emsgs_lock, flags);

		nblocked_emsgs_readers--;

		if (n) {
			spin_unlock_irqrestore(&emsgs_lock, flags);
			return -ERESTARTSYS;
		}
	}
	if (em->len > cnt) {
		spin_unlock_irqrestore(&emsgs_lock, flags);
		return -EAGAIN;
	}
	mp = em->msg;
	len = em->len;
	em->msg = NULL;
	em->flags &= ~EMFL_VALID;

	emsgs_head_idx++;
	emsgs_head_idx %= ARRAY_SIZE(emsgs);

	spin_unlock_irqrestore(&emsgs_lock, flags);

	n = copy_to_user(buf, mp, len);
	kfree(mp);
	return n == 0 ? len : -EFAULT;
}

static const struct file_operations aoe_fops = {
	.write = aoechr_write,
	.read = aoechr_read,
	.open = aoechr_open,
	.release = aoechr_rel,
	.owner = THIS_MODULE,
};

int __init
aoechr_init(void)
{
	int n, i;

	n = register_chrdev(AOE_MAJOR, "aoechr", &aoe_fops);
	if (n < 0) { 
		printk(KERN_ERR "aoe: can't register char device\n");
		return n;
	}
	sema_init(&emsgs_sema, 0);
	spin_lock_init(&emsgs_lock);
	aoe_class = class_create(THIS_MODULE, "aoe");
	if (IS_ERR(aoe_class)) {
		unregister_chrdev(AOE_MAJOR, "aoechr");
		return PTR_ERR(aoe_class);
	}
	for (i = 0; i < ARRAY_SIZE(chardevs); ++i)
		device_create_drvdata(aoe_class, NULL,
				      MKDEV(AOE_MAJOR, chardevs[i].minor),
				      NULL, chardevs[i].name);

	return 0;
}

void
aoechr_exit(void)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(chardevs); ++i)
		device_destroy(aoe_class, MKDEV(AOE_MAJOR, chardevs[i].minor));
	class_destroy(aoe_class);
	unregister_chrdev(AOE_MAJOR, "aoechr");
}
Commit	Line	Data
52e112b3	1	/* Copyright (c) 2007 Coraid, Inc. See COPYING for GPL terms. */
1da177e4 LT	2	/*
	3	* aoechr.c
	4	* AoE character device driver
	5	*/
	6
	7	#include <linux/hdreg.h>
	8	#include <linux/blkdev.h>
68e0d42f	9	#include <linux/delay.h>
579174a5	10	#include <linux/smp_lock.h>
1da177e4 LT	11	#include "aoe.h"
	12
	13	enum {
	14	//MINOR_STAT = 1, (moved to sysfs)
	15	MINOR_ERR = 2,
	16	MINOR_DISCOVER,
	17	MINOR_INTERFACES,
3ae1c24e	18	MINOR_REVALIDATE,
262bf541	19	MINOR_FLUSH,
1da177e4	20	MSGSZ = 2048,
1da177e4 LT	21	NMSG = 100, /* message backlog to retain */
	22	};
	23
	24	struct aoe_chardev {
	25	ulong minor;
	26	char name[32];
	27	};
	28
	29	enum { EMFL_VALID = 1 };
	30
	31	struct ErrMsg {
	32	short flags;
	33	short len;
	34	char *msg;
	35	};
	36
	37	static struct ErrMsg emsgs[NMSG];
	38	static int emsgs_head_idx, emsgs_tail_idx;
	39	static struct semaphore emsgs_sema;
	40	static spinlock_t emsgs_lock;
	41	static int nblocked_emsgs_readers;
deb36970	42	static struct class *aoe_class;
1da177e4 LT	43	static struct aoe_chardev chardevs[] = {
	44	{ MINOR_ERR, "err" },
	45	{ MINOR_DISCOVER, "discover" },
	46	{ MINOR_INTERFACES, "interfaces" },
3ae1c24e	47	{ MINOR_REVALIDATE, "revalidate" },
262bf541	48	{ MINOR_FLUSH, "flush" },
1da177e4 LT	49	};
	50
	51	static int
	52	discover(void)
	53	{
	54	aoecmd_cfg(0xffff, 0xff);
	55	return 0;
	56	}
	57
	58	static int
	59	interfaces(const char __user *str, size_t size)
	60	{
	61	if (set_aoe_iflist(str, size)) {
a12c93f0 EC	62	printk(KERN_ERR
a12c93f0 EC	63	"aoe: could not set interface list: too many interfaces\n");
1da177e4 LT	64	return -EINVAL;
	65	}
	66	return 0;
	67	}
	68
3ae1c24e EC	69	static int
	70	revalidate(const char __user *str, size_t size)
	71	{
	72	int major, minor, n;
	73	ulong flags;
	74	struct aoedev *d;
68e0d42f	75	struct sk_buff *skb;
3ae1c24e EC	76	char buf[16];
	77
	78	if (size >= sizeof buf)
	79	return -EINVAL;
	80	buf[sizeof buf - 1] = '\0';
	81	if (copy_from_user(buf, str, size))
	82	return -EFAULT;
	83
	84	/* should be e%d.%d format */
	85	n = sscanf(buf, "e%d.%d", &major, &minor);
	86	if (n != 2) {
a12c93f0	87	printk(KERN_ERR "aoe: invalid device specification\n");
3ae1c24e EC	88	return -EINVAL;
	89	}
	90	d = aoedev_by_aoeaddr(major, minor);
	91	if (!d)
	92	return -EINVAL;
3ae1c24e	93	spin_lock_irqsave(&d->lock, flags);
68e0d42f EC	94	aoecmd_cleanslate(d);
	95	loop:
	96	skb = aoecmd_ata_id(d);
3ae1c24e	97	spin_unlock_irqrestore(&d->lock, flags);
68e0d42f EC	98	/* try again if we are able to sleep a bit,
	99	* otherwise give up this revalidation
	100	*/
	101	if (!skb && !msleep_interruptible(200)) {
	102	spin_lock_irqsave(&d->lock, flags);
	103	goto loop;
	104	}
	105	aoenet_xmit(skb);
3ae1c24e	106	aoecmd_cfg(major, minor);
3ae1c24e EC	107	return 0;
	108	}
	109
1da177e4 LT	110	void
	111	aoechr_error(char *msg)
	112	{
	113	struct ErrMsg *em;
	114	char *mp;
	115	ulong flags, n;
	116
	117	n = strlen(msg);
	118
	119	spin_lock_irqsave(&emsgs_lock, flags);
	120
	121	em = emsgs + emsgs_tail_idx;
	122	if ((em->flags & EMFL_VALID)) {
	123	bail: spin_unlock_irqrestore(&emsgs_lock, flags);
	124	return;
	125	}
	126
	127	mp = kmalloc(n, GFP_ATOMIC);
	128	if (mp == NULL) {
a12c93f0	129	printk(KERN_ERR "aoe: allocation failure, len=%ld\n", n);
1da177e4 LT	130	goto bail;
	131	}
	132
	133	memcpy(mp, msg, n);
	134	em->msg = mp;
	135	em->flags \|= EMFL_VALID;
	136	em->len = n;
	137
	138	emsgs_tail_idx++;
	139	emsgs_tail_idx %= ARRAY_SIZE(emsgs);
	140
	141	spin_unlock_irqrestore(&emsgs_lock, flags);
	142
	143	if (nblocked_emsgs_readers)
	144	up(&emsgs_sema);
	145	}
	146
	147	static ssize_t
	148	aoechr_write(struct file filp, const char __user buf, size_t cnt, loff_t *offp)
	149	{
	150	int ret = -EINVAL;
	151
	152	switch ((unsigned long) filp->private_data) {
	153	default:
a12c93f0	154	printk(KERN_INFO "aoe: can't write to that file.\n");
1da177e4 LT	155	break;
	156	case MINOR_DISCOVER:
	157	ret = discover();
	158	break;
	159	case MINOR_INTERFACES:
	160	ret = interfaces(buf, cnt);
	161	break;
3ae1c24e EC	162	case MINOR_REVALIDATE:
3ae1c24e EC	163	ret = revalidate(buf, cnt);
262bf541 EC	164	break;
	165	case MINOR_FLUSH:
	166	ret = aoedev_flush(buf, cnt);
1da177e4 LT	167	}
	168	if (ret == 0)
	169	ret = cnt;
	170	return ret;
	171	}
	172
	173	static int
	174	aoechr_open(struct inode inode, struct file filp)
	175	{
	176	int n, i;
	177
579174a5	178	lock_kernel();
2017b376	179	n = iminor(inode);
1da177e4 LT	180	filp->private_data = (void *) (unsigned long) n;
	181
	182	for (i = 0; i < ARRAY_SIZE(chardevs); ++i)
579174a5 JC	183	if (chardevs[i].minor == n) {
579174a5 JC	184	unlock_kernel();
1da177e4	185	return 0;
579174a5 JC	186	}
579174a5 JC	187	unlock_kernel();
1da177e4 LT	188	return -EINVAL;
	189	}
	190
	191	static int
	192	aoechr_rel(struct inode inode, struct file filp)
	193	{
	194	return 0;
	195	}
	196
	197	static ssize_t
	198	aoechr_read(struct file filp, char __user buf, size_t cnt, loff_t *off)
	199	{
	200	unsigned long n;
	201	char *mp;
	202	struct ErrMsg *em;
	203	ssize_t len;
	204	ulong flags;
	205
	206	n = (unsigned long) filp->private_data;
cf446f0d EC	207	if (n != MINOR_ERR)
	208	return -EFAULT;
	209
	210	spin_lock_irqsave(&emsgs_lock, flags);
1da177e4	211
cf446f0d EC	212	for (;;) {
	213	em = emsgs + emsgs_head_idx;
	214	if ((em->flags & EMFL_VALID) != 0)
	215	break;
	216	if (filp->f_flags & O_NDELAY) {
1da177e4	217	spin_unlock_irqrestore(&emsgs_lock, flags);
cf446f0d EC	218	return -EAGAIN;
	219	}
	220	nblocked_emsgs_readers++;
	221
	222	spin_unlock_irqrestore(&emsgs_lock, flags);
1da177e4	223
cf446f0d	224	n = down_interruptible(&emsgs_sema);
1da177e4	225
cf446f0d	226	spin_lock_irqsave(&emsgs_lock, flags);
1da177e4	227
cf446f0d	228	nblocked_emsgs_readers--;
1da177e4	229
cf446f0d	230	if (n) {
1da177e4	231	spin_unlock_irqrestore(&emsgs_lock, flags);
cf446f0d	232	return -ERESTARTSYS;
1da177e4	233	}
cf446f0d EC	234	}
	235	if (em->len > cnt) {
	236	spin_unlock_irqrestore(&emsgs_lock, flags);
	237	return -EAGAIN;
	238	}
	239	mp = em->msg;
	240	len = em->len;
	241	em->msg = NULL;
	242	em->flags &= ~EMFL_VALID;
1da177e4	243
cf446f0d EC	244	emsgs_head_idx++;
cf446f0d EC	245	emsgs_head_idx %= ARRAY_SIZE(emsgs);
1da177e4	246
cf446f0d	247	spin_unlock_irqrestore(&emsgs_lock, flags);
1da177e4	248
cf446f0d EC	249	n = copy_to_user(buf, mp, len);
	250	kfree(mp);
	251	return n == 0 ? len : -EFAULT;
1da177e4 LT	252	}
1da177e4 LT	253
2b8693c0	254	static const struct file_operations aoe_fops = {
1da177e4 LT	255	.write = aoechr_write,
	256	.read = aoechr_read,
	257	.open = aoechr_open,
	258	.release = aoechr_rel,
	259	.owner = THIS_MODULE,
	260	};
	261
	262	int __init
	263	aoechr_init(void)
	264	{
	265	int n, i;
	266
	267	n = register_chrdev(AOE_MAJOR, "aoechr", &aoe_fops);
	268	if (n < 0) {
a12c93f0	269	printk(KERN_ERR "aoe: can't register char device\n");
1da177e4 LT	270	return n;
	271	}
	272	sema_init(&emsgs_sema, 0);
	273	spin_lock_init(&emsgs_lock);
deb36970	274	aoe_class = class_create(THIS_MODULE, "aoe");
1da177e4 LT	275	if (IS_ERR(aoe_class)) {
	276	unregister_chrdev(AOE_MAJOR, "aoechr");
	277	return PTR_ERR(aoe_class);
	278	}
	279	for (i = 0; i < ARRAY_SIZE(chardevs); ++i)
f79f0605 GKH	280	device_create_drvdata(aoe_class, NULL,
	281	MKDEV(AOE_MAJOR, chardevs[i].minor),
	282	NULL, chardevs[i].name);
1da177e4 LT	283
	284	return 0;
	285	}
	286
	287	void
	288	aoechr_exit(void)
	289	{
	290	int i;
	291
	292	for (i = 0; i < ARRAY_SIZE(chardevs); ++i)
7ea7ed01	293	device_destroy(aoe_class, MKDEV(AOE_MAJOR, chardevs[i].minor));
deb36970	294	class_destroy(aoe_class);
1da177e4 LT	295	unregister_chrdev(AOE_MAJOR, "aoechr");
	296	}
	297