[mirror_ubuntu-zesty-kernel.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/completion.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/smp_lock.h>
#include <linux/skbuff.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 completion emsgs_comp;
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;
	}
	if (skb) {
		struct sk_buff_head queue;
		__skb_queue_head_init(&queue);
		__skb_queue_tail(&queue, skb);
		aoenet_xmit(&queue);
	}
	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)
		complete(&emsgs_comp);
}

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 = wait_for_completion_interruptible(&emsgs_comp);

		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,
};

static char *aoe_devnode(struct device *dev, mode_t *mode)
{
	return kasprintf(GFP_KERNEL, "etherd/%s", dev_name(dev));
}

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;
	}
	init_completion(&emsgs_comp);
	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);
	}
	aoe_class->devnode = aoe_devnode;

	for (i = 0; i < ARRAY_SIZE(chardevs); ++i)
		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)
		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>
24879a8e	9	#include <linux/completion.h>
68e0d42f	10	#include <linux/delay.h>
5a0e3ad6	11	#include <linux/slab.h>
579174a5	12	#include <linux/smp_lock.h>
e9bb8fb0	13	#include <linux/skbuff.h>
1da177e4 LT	14	#include "aoe.h"
	15
	16	enum {
	17	//MINOR_STAT = 1, (moved to sysfs)
	18	MINOR_ERR = 2,
	19	MINOR_DISCOVER,
	20	MINOR_INTERFACES,
3ae1c24e	21	MINOR_REVALIDATE,
262bf541	22	MINOR_FLUSH,
1da177e4	23	MSGSZ = 2048,
1da177e4 LT	24	NMSG = 100, /* message backlog to retain */
	25	};
	26
	27	struct aoe_chardev {
	28	ulong minor;
	29	char name[32];
	30	};
	31
	32	enum { EMFL_VALID = 1 };
	33
	34	struct ErrMsg {
	35	short flags;
	36	short len;
	37	char *msg;
	38	};
	39
	40	static struct ErrMsg emsgs[NMSG];
	41	static int emsgs_head_idx, emsgs_tail_idx;
24879a8e	42	static struct completion emsgs_comp;
1da177e4 LT	43	static spinlock_t emsgs_lock;
1da177e4 LT	44	static int nblocked_emsgs_readers;
deb36970	45	static struct class *aoe_class;
1da177e4 LT	46	static struct aoe_chardev chardevs[] = {
	47	{ MINOR_ERR, "err" },
	48	{ MINOR_DISCOVER, "discover" },
	49	{ MINOR_INTERFACES, "interfaces" },
3ae1c24e	50	{ MINOR_REVALIDATE, "revalidate" },
262bf541	51	{ MINOR_FLUSH, "flush" },
1da177e4 LT	52	};
	53
	54	static int
	55	discover(void)
	56	{
	57	aoecmd_cfg(0xffff, 0xff);
	58	return 0;
	59	}
	60
	61	static int
	62	interfaces(const char __user *str, size_t size)
	63	{
	64	if (set_aoe_iflist(str, size)) {
a12c93f0 EC	65	printk(KERN_ERR
a12c93f0 EC	66	"aoe: could not set interface list: too many interfaces\n");
1da177e4 LT	67	return -EINVAL;
	68	}
	69	return 0;
	70	}
	71
3ae1c24e EC	72	static int
	73	revalidate(const char __user *str, size_t size)
	74	{
	75	int major, minor, n;
	76	ulong flags;
	77	struct aoedev *d;
68e0d42f	78	struct sk_buff *skb;
3ae1c24e EC	79	char buf[16];
	80
	81	if (size >= sizeof buf)
	82	return -EINVAL;
	83	buf[sizeof buf - 1] = '\0';
	84	if (copy_from_user(buf, str, size))
	85	return -EFAULT;
	86
	87	/* should be e%d.%d format */
	88	n = sscanf(buf, "e%d.%d", &major, &minor);
	89	if (n != 2) {
a12c93f0	90	printk(KERN_ERR "aoe: invalid device specification\n");
3ae1c24e EC	91	return -EINVAL;
	92	}
	93	d = aoedev_by_aoeaddr(major, minor);
	94	if (!d)
	95	return -EINVAL;
3ae1c24e	96	spin_lock_irqsave(&d->lock, flags);
68e0d42f EC	97	aoecmd_cleanslate(d);
	98	loop:
	99	skb = aoecmd_ata_id(d);
3ae1c24e	100	spin_unlock_irqrestore(&d->lock, flags);
68e0d42f EC	101	/* try again if we are able to sleep a bit,
	102	* otherwise give up this revalidation
	103	*/
	104	if (!skb && !msleep_interruptible(200)) {
	105	spin_lock_irqsave(&d->lock, flags);
	106	goto loop;
	107	}
e9bb8fb0 DM	108	if (skb) {
	109	struct sk_buff_head queue;
	110	__skb_queue_head_init(&queue);
	111	__skb_queue_tail(&queue, skb);
	112	aoenet_xmit(&queue);
	113	}
3ae1c24e	114	aoecmd_cfg(major, minor);
3ae1c24e EC	115	return 0;
	116	}
	117
1da177e4 LT	118	void
	119	aoechr_error(char *msg)
	120	{
	121	struct ErrMsg *em;
	122	char *mp;
	123	ulong flags, n;
	124
	125	n = strlen(msg);
	126
	127	spin_lock_irqsave(&emsgs_lock, flags);
	128
	129	em = emsgs + emsgs_tail_idx;
	130	if ((em->flags & EMFL_VALID)) {
	131	bail: spin_unlock_irqrestore(&emsgs_lock, flags);
	132	return;
	133	}
	134
	135	mp = kmalloc(n, GFP_ATOMIC);
	136	if (mp == NULL) {
a12c93f0	137	printk(KERN_ERR "aoe: allocation failure, len=%ld\n", n);
1da177e4 LT	138	goto bail;
	139	}
	140
	141	memcpy(mp, msg, n);
	142	em->msg = mp;
	143	em->flags \|= EMFL_VALID;
	144	em->len = n;
	145
	146	emsgs_tail_idx++;
	147	emsgs_tail_idx %= ARRAY_SIZE(emsgs);
	148
	149	spin_unlock_irqrestore(&emsgs_lock, flags);
	150
	151	if (nblocked_emsgs_readers)
24879a8e	152	complete(&emsgs_comp);
1da177e4 LT	153	}
	154
	155	static ssize_t
	156	aoechr_write(struct file filp, const char __user buf, size_t cnt, loff_t *offp)
	157	{
	158	int ret = -EINVAL;
	159
	160	switch ((unsigned long) filp->private_data) {
	161	default:
a12c93f0	162	printk(KERN_INFO "aoe: can't write to that file.\n");
1da177e4 LT	163	break;
	164	case MINOR_DISCOVER:
	165	ret = discover();
	166	break;
	167	case MINOR_INTERFACES:
	168	ret = interfaces(buf, cnt);
	169	break;
3ae1c24e EC	170	case MINOR_REVALIDATE:
3ae1c24e EC	171	ret = revalidate(buf, cnt);
262bf541 EC	172	break;
	173	case MINOR_FLUSH:
	174	ret = aoedev_flush(buf, cnt);
1da177e4 LT	175	}
	176	if (ret == 0)
	177	ret = cnt;
	178	return ret;
	179	}
	180
	181	static int
	182	aoechr_open(struct inode inode, struct file filp)
	183	{
	184	int n, i;
	185
579174a5	186	lock_kernel();
2017b376	187	n = iminor(inode);
1da177e4 LT	188	filp->private_data = (void *) (unsigned long) n;
	189
	190	for (i = 0; i < ARRAY_SIZE(chardevs); ++i)
579174a5 JC	191	if (chardevs[i].minor == n) {
579174a5 JC	192	unlock_kernel();
1da177e4	193	return 0;
579174a5 JC	194	}
579174a5 JC	195	unlock_kernel();
1da177e4 LT	196	return -EINVAL;
	197	}
	198
	199	static int
	200	aoechr_rel(struct inode inode, struct file filp)
	201	{
	202	return 0;
	203	}
	204
	205	static ssize_t
	206	aoechr_read(struct file filp, char __user buf, size_t cnt, loff_t *off)
	207	{
	208	unsigned long n;
	209	char *mp;
	210	struct ErrMsg *em;
	211	ssize_t len;
	212	ulong flags;
	213
	214	n = (unsigned long) filp->private_data;
cf446f0d EC	215	if (n != MINOR_ERR)
	216	return -EFAULT;
	217
	218	spin_lock_irqsave(&emsgs_lock, flags);
1da177e4	219
cf446f0d EC	220	for (;;) {
	221	em = emsgs + emsgs_head_idx;
	222	if ((em->flags & EMFL_VALID) != 0)
	223	break;
	224	if (filp->f_flags & O_NDELAY) {
1da177e4	225	spin_unlock_irqrestore(&emsgs_lock, flags);
cf446f0d EC	226	return -EAGAIN;
	227	}
	228	nblocked_emsgs_readers++;
	229
	230	spin_unlock_irqrestore(&emsgs_lock, flags);
1da177e4	231
24879a8e	232	n = wait_for_completion_interruptible(&emsgs_comp);
1da177e4	233
cf446f0d	234	spin_lock_irqsave(&emsgs_lock, flags);
1da177e4	235
cf446f0d	236	nblocked_emsgs_readers--;
1da177e4	237
cf446f0d	238	if (n) {
1da177e4	239	spin_unlock_irqrestore(&emsgs_lock, flags);
cf446f0d	240	return -ERESTARTSYS;
1da177e4	241	}
cf446f0d EC	242	}
	243	if (em->len > cnt) {
	244	spin_unlock_irqrestore(&emsgs_lock, flags);
	245	return -EAGAIN;
	246	}
	247	mp = em->msg;
	248	len = em->len;
	249	em->msg = NULL;
	250	em->flags &= ~EMFL_VALID;
1da177e4	251
cf446f0d EC	252	emsgs_head_idx++;
cf446f0d EC	253	emsgs_head_idx %= ARRAY_SIZE(emsgs);
1da177e4	254
cf446f0d	255	spin_unlock_irqrestore(&emsgs_lock, flags);
1da177e4	256
cf446f0d EC	257	n = copy_to_user(buf, mp, len);
	258	kfree(mp);
	259	return n == 0 ? len : -EFAULT;
1da177e4 LT	260	}
1da177e4 LT	261
2b8693c0	262	static const struct file_operations aoe_fops = {
1da177e4 LT	263	.write = aoechr_write,
	264	.read = aoechr_read,
	265	.open = aoechr_open,
	266	.release = aoechr_rel,
	267	.owner = THIS_MODULE,
	268	};
	269
e454cea2	270	static char aoe_devnode(struct device dev, mode_t *mode)
1ce8a0d3 KS	271	{
	272	return kasprintf(GFP_KERNEL, "etherd/%s", dev_name(dev));
	273	}
	274
1da177e4 LT	275	int __init
	276	aoechr_init(void)
	277	{
	278	int n, i;
	279
	280	n = register_chrdev(AOE_MAJOR, "aoechr", &aoe_fops);
	281	if (n < 0) {
a12c93f0	282	printk(KERN_ERR "aoe: can't register char device\n");
1da177e4 LT	283	return n;
1da177e4 LT	284	}
24879a8e	285	init_completion(&emsgs_comp);
1da177e4	286	spin_lock_init(&emsgs_lock);
deb36970	287	aoe_class = class_create(THIS_MODULE, "aoe");
1da177e4 LT	288	if (IS_ERR(aoe_class)) {
	289	unregister_chrdev(AOE_MAJOR, "aoechr");
	290	return PTR_ERR(aoe_class);
	291	}
e454cea2	292	aoe_class->devnode = aoe_devnode;
1ce8a0d3	293
1da177e4	294	for (i = 0; i < ARRAY_SIZE(chardevs); ++i)
1ff9f542 GKH	295	device_create(aoe_class, NULL,
	296	MKDEV(AOE_MAJOR, chardevs[i].minor), NULL,
	297	chardevs[i].name);
1da177e4 LT	298
	299	return 0;
	300	}
	301
	302	void
	303	aoechr_exit(void)
	304	{
	305	int i;
	306
	307	for (i = 0; i < ARRAY_SIZE(chardevs); ++i)
7ea7ed01	308	device_destroy(aoe_class, MKDEV(AOE_MAJOR, chardevs[i].minor));
deb36970	309	class_destroy(aoe_class);
1da177e4 LT	310	unregister_chrdev(AOE_MAJOR, "aoechr");
	311	}
	312