diff options
Diffstat (limited to 'drivers/block/aoe/aoechr.c')
| -rw-r--r-- | drivers/block/aoe/aoechr.c | 244 |
1 files changed, 244 insertions, 0 deletions
diff --git a/drivers/block/aoe/aoechr.c b/drivers/block/aoe/aoechr.c new file mode 100644 index 000000000000..14aeca3e2e8c --- /dev/null +++ b/drivers/block/aoe/aoechr.c @@ -0,0 +1,244 @@ +/* Copyright (c) 2004 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, + MSGSZ = 2048, + NARGS = 10, + 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_simple *aoe_class; +static struct aoe_chardev chardevs[] = { + { MINOR_ERR, "err" }, + { MINOR_DISCOVER, "discover" }, + { MINOR_INTERFACES, "interfaces" }, +}; + +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_CRIT + "%s: could not set interface list: %s\n", + __FUNCTION__, "too many interfaces"); + return -EINVAL; + } + 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_CRIT "aoe: aoechr_error: 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: aoechr_write: can't write to that file.\n"); + break; + case MINOR_DISCOVER: + ret = discover(); + break; + case MINOR_INTERFACES: + ret = interfaces(buf, cnt); + break; + } + if (ret == 0) + ret = cnt; + return ret; +} + +static int +aoechr_open(struct inode *inode, struct file *filp) +{ + int n, i; + + n = MINOR(inode->i_rdev); + 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) { + printk(KERN_ERR "aoe: aoechr_init: can't register char device\n"); + return n; + } + sema_init(&emsgs_sema, 0); + spin_lock_init(&emsgs_lock); + aoe_class = class_simple_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_simple_device_add(aoe_class, + 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_simple_device_remove(MKDEV(AOE_MAJOR, chardevs[i].minor)); + class_simple_destroy(aoe_class); + unregister_chrdev(AOE_MAJOR, "aoechr"); +} + |