1 /* Copyright (c) 2012 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/completion.h>
10 #include <linux/delay.h>
11 #include <linux/slab.h>
12 #include <linux/mutex.h>
13 #include <linux/skbuff.h>
14 #include <linux/export.h>
18 //MINOR_STAT = 1, (moved to sysfs)
25 NMSG = 100, /* message backlog to retain */
33 enum { EMFL_VALID = 1 };
41 static DEFINE_MUTEX(aoechr_mutex);
42 static struct ErrMsg emsgs[NMSG];
43 static int emsgs_head_idx, emsgs_tail_idx;
44 static struct completion emsgs_comp;
45 static spinlock_t emsgs_lock;
46 static int nblocked_emsgs_readers;
47 static struct class *aoe_class;
48 static struct aoe_chardev chardevs[] = {
50 { MINOR_DISCOVER, "discover" },
51 { MINOR_INTERFACES, "interfaces" },
52 { MINOR_REVALIDATE, "revalidate" },
53 { MINOR_FLUSH, "flush" },
59 aoecmd_cfg(0xffff, 0xff);
64 interfaces(const char __user *str, size_t size)
66 if (set_aoe_iflist(str, size)) {
68 "aoe: could not set interface list: too many interfaces\n");
75 revalidate(const char __user *str, size_t size)
83 if (size >= sizeof buf)
85 buf[sizeof buf - 1] = '\0';
86 if (copy_from_user(buf, str, size))
89 n = sscanf(buf, "e%d.%d", &major, &minor);
91 pr_err("aoe: invalid device specification %s\n", buf);
94 d = aoedev_by_aoeaddr(major, minor, 0);
97 spin_lock_irqsave(&d->lock, flags);
99 aoecmd_cfg(major, minor);
101 skb = aoecmd_ata_id(d);
102 spin_unlock_irqrestore(&d->lock, flags);
103 /* try again if we are able to sleep a bit,
104 * otherwise give up this revalidation
106 if (!skb && !msleep_interruptible(250)) {
107 spin_lock_irqsave(&d->lock, flags);
112 struct sk_buff_head queue;
113 __skb_queue_head_init(&queue);
114 __skb_queue_tail(&queue, skb);
121 aoechr_error(char *msg)
129 spin_lock_irqsave(&emsgs_lock, flags);
131 em = emsgs + emsgs_tail_idx;
132 if ((em->flags & EMFL_VALID)) {
133 bail: spin_unlock_irqrestore(&emsgs_lock, flags);
137 mp = kmalloc(n, GFP_ATOMIC);
139 printk(KERN_ERR "aoe: allocation failure, len=%ld\n", n);
145 em->flags |= EMFL_VALID;
149 emsgs_tail_idx %= ARRAY_SIZE(emsgs);
151 spin_unlock_irqrestore(&emsgs_lock, flags);
153 if (nblocked_emsgs_readers)
154 complete(&emsgs_comp);
158 aoechr_write(struct file *filp, const char __user *buf, size_t cnt, loff_t *offp)
162 switch ((unsigned long) filp->private_data) {
164 printk(KERN_INFO "aoe: can't write to that file.\n");
169 case MINOR_INTERFACES:
170 ret = interfaces(buf, cnt);
172 case MINOR_REVALIDATE:
173 ret = revalidate(buf, cnt);
176 ret = aoedev_flush(buf, cnt);
185 aoechr_open(struct inode *inode, struct file *filp)
189 mutex_lock(&aoechr_mutex);
191 filp->private_data = (void *) (unsigned long) n;
193 for (i = 0; i < ARRAY_SIZE(chardevs); ++i)
194 if (chardevs[i].minor == n) {
195 mutex_unlock(&aoechr_mutex);
198 mutex_unlock(&aoechr_mutex);
203 aoechr_rel(struct inode *inode, struct file *filp)
209 aoechr_read(struct file *filp, char __user *buf, size_t cnt, loff_t *off)
217 n = (unsigned long) filp->private_data;
221 spin_lock_irqsave(&emsgs_lock, flags);
224 em = emsgs + emsgs_head_idx;
225 if ((em->flags & EMFL_VALID) != 0)
227 if (filp->f_flags & O_NDELAY) {
228 spin_unlock_irqrestore(&emsgs_lock, flags);
231 nblocked_emsgs_readers++;
233 spin_unlock_irqrestore(&emsgs_lock, flags);
235 n = wait_for_completion_interruptible(&emsgs_comp);
237 spin_lock_irqsave(&emsgs_lock, flags);
239 nblocked_emsgs_readers--;
242 spin_unlock_irqrestore(&emsgs_lock, flags);
247 spin_unlock_irqrestore(&emsgs_lock, flags);
253 em->flags &= ~EMFL_VALID;
256 emsgs_head_idx %= ARRAY_SIZE(emsgs);
258 spin_unlock_irqrestore(&emsgs_lock, flags);
260 n = copy_to_user(buf, mp, len);
262 return n == 0 ? len : -EFAULT;
265 static const struct file_operations aoe_fops = {
266 .write = aoechr_write,
269 .release = aoechr_rel,
270 .owner = THIS_MODULE,
271 .llseek = noop_llseek,
274 static char *aoe_devnode(struct device *dev, umode_t *mode)
276 return kasprintf(GFP_KERNEL, "etherd/%s", dev_name(dev));
284 n = register_chrdev(AOE_MAJOR, "aoechr", &aoe_fops);
286 printk(KERN_ERR "aoe: can't register char device\n");
289 init_completion(&emsgs_comp);
290 spin_lock_init(&emsgs_lock);
291 aoe_class = class_create(THIS_MODULE, "aoe");
292 if (IS_ERR(aoe_class)) {
293 unregister_chrdev(AOE_MAJOR, "aoechr");
294 return PTR_ERR(aoe_class);
296 aoe_class->devnode = aoe_devnode;
298 for (i = 0; i < ARRAY_SIZE(chardevs); ++i)
299 device_create(aoe_class, NULL,
300 MKDEV(AOE_MAJOR, chardevs[i].minor), NULL,
311 for (i = 0; i < ARRAY_SIZE(chardevs); ++i)
312 device_destroy(aoe_class, MKDEV(AOE_MAJOR, chardevs[i].minor));
313 class_destroy(aoe_class);
314 unregister_chrdev(AOE_MAJOR, "aoechr");