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/* 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)
device_create(aoe_class, NULL,
MKDEV(AOE_MAJOR, chardevs[i].minor), 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");
}
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