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

/* Copyright (c) 2006 Coraid, Inc.  See COPYING for GPL terms. */
/*
 * aoechr.c
 * AoE character device driver
 */

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

enum {
	//MINOR_STAT = 1, (moved to sysfs)
	MINOR_ERR = 2,
	MINOR_DISCOVER,
	MINOR_INTERFACES,
	MINOR_REVALIDATE,
	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" },
};

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;
	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);
	d->flags &= ~DEVFL_MAXBCNT;
	d->flags |= DEVFL_PAUSE;
	spin_unlock_irqrestore(&d->lock, flags);
	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);
	}
	if (ret == 0)
		ret = cnt;
	return ret;
}

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

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

	for (i = 0; i < ARRAY_SIZE(chardevs); ++i)
		if (chardevs[i].minor == n)
			return 0;
	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;
	switch (n) {
	case MINOR_ERR:
		spin_lock_irqsave(&emsgs_lock, flags);
loop:
		em = emsgs + emsgs_head_idx;
		if ((em->flags & EMFL_VALID) == 0) {
			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;
			}
			goto loop;
		}
		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;
	default:
		return -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)
		class_device_create(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)
		class_device_destroy(aoe_class, MKDEV(AOE_MAJOR, chardevs[i].minor));
	class_destroy(aoe_class);
	unregister_chrdev(AOE_MAJOR, "aoechr");
}
Commit	Line	Data
2611464d	1	/* Copyright (c) 2006 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>
	9	#include "aoe.h"
	10
	11	enum {
	12	//MINOR_STAT = 1, (moved to sysfs)
	13	MINOR_ERR = 2,
	14	MINOR_DISCOVER,
	15	MINOR_INTERFACES,
3ae1c24e	16	MINOR_REVALIDATE,
1da177e4	17	MSGSZ = 2048,
1da177e4 LT	18	NMSG = 100, /* message backlog to retain */
	19	};
	20
	21	struct aoe_chardev {
	22	ulong minor;
	23	char name[32];
	24	};
	25
	26	enum { EMFL_VALID = 1 };
	27
	28	struct ErrMsg {
	29	short flags;
	30	short len;
	31	char *msg;
	32	};
	33
	34	static struct ErrMsg emsgs[NMSG];
	35	static int emsgs_head_idx, emsgs_tail_idx;
	36	static struct semaphore emsgs_sema;
	37	static spinlock_t emsgs_lock;
	38	static int nblocked_emsgs_readers;
deb36970	39	static struct class *aoe_class;
1da177e4 LT	40	static struct aoe_chardev chardevs[] = {
	41	{ MINOR_ERR, "err" },
	42	{ MINOR_DISCOVER, "discover" },
	43	{ MINOR_INTERFACES, "interfaces" },
3ae1c24e	44	{ MINOR_REVALIDATE, "revalidate" },
1da177e4 LT	45	};
	46
	47	static int
	48	discover(void)
	49	{
	50	aoecmd_cfg(0xffff, 0xff);
	51	return 0;
	52	}
	53
	54	static int
	55	interfaces(const char __user *str, size_t size)
	56	{
	57	if (set_aoe_iflist(str, size)) {
a12c93f0 EC	58	printk(KERN_ERR
a12c93f0 EC	59	"aoe: could not set interface list: too many interfaces\n");
1da177e4 LT	60	return -EINVAL;
	61	}
	62	return 0;
	63	}
	64
3ae1c24e EC	65	static int
	66	revalidate(const char __user *str, size_t size)
	67	{
	68	int major, minor, n;
	69	ulong flags;
	70	struct aoedev *d;
	71	char buf[16];
	72
	73	if (size >= sizeof buf)
	74	return -EINVAL;
	75	buf[sizeof buf - 1] = '\0';
	76	if (copy_from_user(buf, str, size))
	77	return -EFAULT;
	78
	79	/* should be e%d.%d format */
	80	n = sscanf(buf, "e%d.%d", &major, &minor);
	81	if (n != 2) {
a12c93f0	82	printk(KERN_ERR "aoe: invalid device specification\n");
3ae1c24e EC	83	return -EINVAL;
	84	}
	85	d = aoedev_by_aoeaddr(major, minor);
	86	if (!d)
	87	return -EINVAL;
	88
	89	spin_lock_irqsave(&d->lock, flags);
19bf2635	90	d->flags &= ~DEVFL_MAXBCNT;
3ae1c24e EC	91	d->flags \|= DEVFL_PAUSE;
	92	spin_unlock_irqrestore(&d->lock, flags);
	93	aoecmd_cfg(major, minor);
	94
	95	return 0;
	96	}
	97
1da177e4 LT	98	void
	99	aoechr_error(char *msg)
	100	{
	101	struct ErrMsg *em;
	102	char *mp;
	103	ulong flags, n;
	104
	105	n = strlen(msg);
	106
	107	spin_lock_irqsave(&emsgs_lock, flags);
	108
	109	em = emsgs + emsgs_tail_idx;
	110	if ((em->flags & EMFL_VALID)) {
	111	bail: spin_unlock_irqrestore(&emsgs_lock, flags);
	112	return;
	113	}
	114
	115	mp = kmalloc(n, GFP_ATOMIC);
	116	if (mp == NULL) {
a12c93f0	117	printk(KERN_ERR "aoe: allocation failure, len=%ld\n", n);
1da177e4 LT	118	goto bail;
	119	}
	120
	121	memcpy(mp, msg, n);
	122	em->msg = mp;
	123	em->flags \|= EMFL_VALID;
	124	em->len = n;
	125
	126	emsgs_tail_idx++;
	127	emsgs_tail_idx %= ARRAY_SIZE(emsgs);
	128
	129	spin_unlock_irqrestore(&emsgs_lock, flags);
	130
	131	if (nblocked_emsgs_readers)
	132	up(&emsgs_sema);
	133	}
	134
	135	static ssize_t
	136	aoechr_write(struct file filp, const char __user buf, size_t cnt, loff_t *offp)
	137	{
	138	int ret = -EINVAL;
	139
	140	switch ((unsigned long) filp->private_data) {
	141	default:
a12c93f0	142	printk(KERN_INFO "aoe: can't write to that file.\n");
1da177e4 LT	143	break;
	144	case MINOR_DISCOVER:
	145	ret = discover();
	146	break;
	147	case MINOR_INTERFACES:
	148	ret = interfaces(buf, cnt);
	149	break;
3ae1c24e EC	150	case MINOR_REVALIDATE:
3ae1c24e EC	151	ret = revalidate(buf, cnt);
1da177e4 LT	152	}
	153	if (ret == 0)
	154	ret = cnt;
	155	return ret;
	156	}
	157
	158	static int
	159	aoechr_open(struct inode inode, struct file filp)
	160	{
	161	int n, i;
	162
2017b376	163	n = iminor(inode);
1da177e4 LT	164	filp->private_data = (void *) (unsigned long) n;
	165
	166	for (i = 0; i < ARRAY_SIZE(chardevs); ++i)
	167	if (chardevs[i].minor == n)
	168	return 0;
	169	return -EINVAL;
	170	}
	171
	172	static int
	173	aoechr_rel(struct inode inode, struct file filp)
	174	{
	175	return 0;
	176	}
	177
	178	static ssize_t
	179	aoechr_read(struct file filp, char __user buf, size_t cnt, loff_t *off)
	180	{
	181	unsigned long n;
	182	char *mp;
	183	struct ErrMsg *em;
	184	ssize_t len;
	185	ulong flags;
	186
	187	n = (unsigned long) filp->private_data;
	188	switch (n) {
	189	case MINOR_ERR:
	190	spin_lock_irqsave(&emsgs_lock, flags);
	191	loop:
	192	em = emsgs + emsgs_head_idx;
	193	if ((em->flags & EMFL_VALID) == 0) {
	194	if (filp->f_flags & O_NDELAY) {
	195	spin_unlock_irqrestore(&emsgs_lock, flags);
	196	return -EAGAIN;
	197	}
	198	nblocked_emsgs_readers++;
	199
	200	spin_unlock_irqrestore(&emsgs_lock, flags);
	201
	202	n = down_interruptible(&emsgs_sema);
	203
	204	spin_lock_irqsave(&emsgs_lock, flags);
	205
	206	nblocked_emsgs_readers--;
	207
	208	if (n) {
	209	spin_unlock_irqrestore(&emsgs_lock, flags);
	210	return -ERESTARTSYS;
	211	}
	212	goto loop;
	213	}
	214	if (em->len > cnt) {
	215	spin_unlock_irqrestore(&emsgs_lock, flags);
	216	return -EAGAIN;
	217	}
	218	mp = em->msg;
	219	len = em->len;
	220	em->msg = NULL;
	221	em->flags &= ~EMFL_VALID;
	222
	223	emsgs_head_idx++;
	224	emsgs_head_idx %= ARRAY_SIZE(emsgs);
	225
	226	spin_unlock_irqrestore(&emsgs_lock, flags);
	227
228	n = copy_to_user(buf, mp, len);
229	kfree(mp);
230	return n == 0 ? len : -EFAULT;
231	default:
232	return -EFAULT;
233	}
234	}
235
2b8693c0	236	static const struct file_operations aoe_fops = {
1da177e4 LT	237	.write = aoechr_write,
	238	.read = aoechr_read,
	239	.open = aoechr_open,
	240	.release = aoechr_rel,
	241	.owner = THIS_MODULE,
	242	};
	243
	244	int __init
	245	aoechr_init(void)
	246	{
	247	int n, i;
	248
	249	n = register_chrdev(AOE_MAJOR, "aoechr", &aoe_fops);
	250	if (n < 0) {
a12c93f0	251	printk(KERN_ERR "aoe: can't register char device\n");
1da177e4 LT	252	return n;
	253	}
	254	sema_init(&emsgs_sema, 0);
	255	spin_lock_init(&emsgs_lock);
deb36970	256	aoe_class = class_create(THIS_MODULE, "aoe");
1da177e4 LT	257	if (IS_ERR(aoe_class)) {
	258	unregister_chrdev(AOE_MAJOR, "aoechr");
	259	return PTR_ERR(aoe_class);
	260	}
	261	for (i = 0; i < ARRAY_SIZE(chardevs); ++i)
53f46542	262	class_device_create(aoe_class, NULL,
1da177e4 LT	263	MKDEV(AOE_MAJOR, chardevs[i].minor),
	264	NULL, chardevs[i].name);
	265
	266	return 0;
	267	}
	268
	269	void
	270	aoechr_exit(void)
	271	{
	272	int i;
	273
	274	for (i = 0; i < ARRAY_SIZE(chardevs); ++i)
deb36970 GKH	275	class_device_destroy(aoe_class, MKDEV(AOE_MAJOR, chardevs[i].minor));
deb36970 GKH	276	class_destroy(aoe_class);
1da177e4 LT	277	unregister_chrdev(AOE_MAJOR, "aoechr");
	278	}
	279