| /* 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)) { |
| eprintk("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) { |
| eprintk("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) { |
| eprintk("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: |
| iprintk("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 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) { |
| eprintk("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"); |
| } |
| |