1 /* Copyright (c) 2007 Coraid, Inc. See COPYING for GPL terms. */
4 * AoE character device driver
7 #include <linux/hdreg.h>
8 #include <linux/blkdev.h>
9 #include <linux/delay.h>
10 #include <linux/smp_lock.h>
14 //MINOR_STAT = 1, (moved to sysfs)
21 NMSG = 100, /* message backlog to retain */
29 enum { EMFL_VALID = 1 };
37 static struct ErrMsg emsgs[NMSG];
38 static int emsgs_head_idx, emsgs_tail_idx;
39 static struct semaphore emsgs_sema;
40 static spinlock_t emsgs_lock;
41 static int nblocked_emsgs_readers;
42 static struct class *aoe_class;
43 static struct aoe_chardev chardevs[] = {
45 { MINOR_DISCOVER, "discover" },
46 { MINOR_INTERFACES, "interfaces" },
47 { MINOR_REVALIDATE, "revalidate" },
48 { MINOR_FLUSH, "flush" },
54 aoecmd_cfg(0xffff, 0xff);
59 interfaces(const char __user *str, size_t size)
61 if (set_aoe_iflist(str, size)) {
63 "aoe: could not set interface list: too many interfaces\n");
70 revalidate(const char __user *str, size_t size)
78 if (size >= sizeof buf)
80 buf[sizeof buf - 1] = '\0';
81 if (copy_from_user(buf, str, size))
84 /* should be e%d.%d format */
85 n = sscanf(buf, "e%d.%d", &major, &minor);
87 printk(KERN_ERR "aoe: invalid device specification\n");
90 d = aoedev_by_aoeaddr(major, minor);
93 spin_lock_irqsave(&d->lock, flags);
96 skb = aoecmd_ata_id(d);
97 spin_unlock_irqrestore(&d->lock, flags);
98 /* try again if we are able to sleep a bit,
99 * otherwise give up this revalidation
101 if (!skb && !msleep_interruptible(200)) {
102 spin_lock_irqsave(&d->lock, flags);
106 aoecmd_cfg(major, minor);
111 aoechr_error(char *msg)
119 spin_lock_irqsave(&emsgs_lock, flags);
121 em = emsgs + emsgs_tail_idx;
122 if ((em->flags & EMFL_VALID)) {
123 bail: spin_unlock_irqrestore(&emsgs_lock, flags);
127 mp = kmalloc(n, GFP_ATOMIC);
129 printk(KERN_ERR "aoe: allocation failure, len=%ld\n", n);
135 em->flags |= EMFL_VALID;
139 emsgs_tail_idx %= ARRAY_SIZE(emsgs);
141 spin_unlock_irqrestore(&emsgs_lock, flags);
143 if (nblocked_emsgs_readers)
148 aoechr_write(struct file *filp, const char __user *buf, size_t cnt, loff_t *offp)
152 switch ((unsigned long) filp->private_data) {
154 printk(KERN_INFO "aoe: can't write to that file.\n");
159 case MINOR_INTERFACES:
160 ret = interfaces(buf, cnt);
162 case MINOR_REVALIDATE:
163 ret = revalidate(buf, cnt);
166 ret = aoedev_flush(buf, cnt);
174 aoechr_open(struct inode *inode, struct file *filp)
180 filp->private_data = (void *) (unsigned long) n;
182 for (i = 0; i < ARRAY_SIZE(chardevs); ++i)
183 if (chardevs[i].minor == n) {
192 aoechr_rel(struct inode *inode, struct file *filp)
198 aoechr_read(struct file *filp, char __user *buf, size_t cnt, loff_t *off)
206 n = (unsigned long) filp->private_data;
210 spin_lock_irqsave(&emsgs_lock, flags);
213 em = emsgs + emsgs_head_idx;
214 if ((em->flags & EMFL_VALID) != 0)
216 if (filp->f_flags & O_NDELAY) {
217 spin_unlock_irqrestore(&emsgs_lock, flags);
220 nblocked_emsgs_readers++;
222 spin_unlock_irqrestore(&emsgs_lock, flags);
224 n = down_interruptible(&emsgs_sema);
226 spin_lock_irqsave(&emsgs_lock, flags);
228 nblocked_emsgs_readers--;
231 spin_unlock_irqrestore(&emsgs_lock, flags);
236 spin_unlock_irqrestore(&emsgs_lock, flags);
242 em->flags &= ~EMFL_VALID;
245 emsgs_head_idx %= ARRAY_SIZE(emsgs);
247 spin_unlock_irqrestore(&emsgs_lock, flags);
249 n = copy_to_user(buf, mp, len);
251 return n == 0 ? len : -EFAULT;
254 static const struct file_operations aoe_fops = {
255 .write = aoechr_write,
258 .release = aoechr_rel,
259 .owner = THIS_MODULE,
267 n = register_chrdev(AOE_MAJOR, "aoechr", &aoe_fops);
269 printk(KERN_ERR "aoe: can't register char device\n");
272 sema_init(&emsgs_sema, 0);
273 spin_lock_init(&emsgs_lock);
274 aoe_class = class_create(THIS_MODULE, "aoe");
275 if (IS_ERR(aoe_class)) {
276 unregister_chrdev(AOE_MAJOR, "aoechr");
277 return PTR_ERR(aoe_class);
279 for (i = 0; i < ARRAY_SIZE(chardevs); ++i)
280 device_create(aoe_class, NULL,
281 MKDEV(AOE_MAJOR, chardevs[i].minor), chardevs[i].name);
291 for (i = 0; i < ARRAY_SIZE(chardevs); ++i)
292 device_destroy(aoe_class, MKDEV(AOE_MAJOR, chardevs[i].minor));
293 class_destroy(aoe_class);
294 unregister_chrdev(AOE_MAJOR, "aoechr");