--- /dev/null
+/* Copyright (c) 2012 Coraid, Inc. See COPYING for GPL terms. */
+/*
+ * aoechr.c
+ * AoE character device driver
+ */
+
+#include <linux/hdreg.h>
+#include <linux/blkdev.h>
+#include <linux/completion.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/mutex.h>
+#include <linux/skbuff.h>
+#include <linux/export.h>
+#include "aoe.h"
+
+enum {
+ //MINOR_STAT = 1, (moved to sysfs)
+ MINOR_ERR = 2,
+ MINOR_DISCOVER,
+ MINOR_INTERFACES,
+ MINOR_REVALIDATE,
+ MINOR_FLUSH,
+ 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 DEFINE_MUTEX(aoechr_mutex);
+
+/* A ring buffer of error messages, to be read through
+ * "/dev/etherd/err". When no messages are present,
+ * readers will block waiting for messages to appear.
+ */
+static struct ErrMsg emsgs[NMSG];
+static int emsgs_head_idx, emsgs_tail_idx;
+static struct completion emsgs_comp;
+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" },
+ { MINOR_FLUSH, "flush" },
+};
+
+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;
+ struct sk_buff *skb;
+ char buf[16];
+
+ if (size >= sizeof buf)
+ return -EINVAL;
+ buf[sizeof buf - 1] = '\0';
+ if (copy_from_user(buf, str, size))
+ return -EFAULT;
+
+ n = sscanf(buf, "e%d.%d", &major, &minor);
+ if (n != 2) {
+ pr_err("aoe: invalid device specification %s\n", buf);
+ return -EINVAL;
+ }
+ d = aoedev_by_aoeaddr(major, minor, 0);
+ if (!d)
+ return -EINVAL;
+ spin_lock_irqsave(&d->lock, flags);
+ aoecmd_cleanslate(d);
+ aoecmd_cfg(major, minor);
+loop:
+ skb = aoecmd_ata_id(d);
+ spin_unlock_irqrestore(&d->lock, flags);
+ /* try again if we are able to sleep a bit,
+ * otherwise give up this revalidation
+ */
+ if (!skb && !msleep_interruptible(250)) {
+ spin_lock_irqsave(&d->lock, flags);
+ goto loop;
+ }
+ aoedev_put(d);
+ if (skb) {
+ struct sk_buff_head queue;
+ __skb_queue_head_init(&queue);
+ __skb_queue_tail(&queue, skb);
+ aoenet_xmit(&queue);
+ }
+ 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 = kmemdup(msg, n, GFP_ATOMIC);
+ if (mp == NULL) {
+ printk(KERN_ERR "aoe: allocation failure, len=%ld\n", n);
+ goto bail;
+ }
+
+ 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)
+ complete(&emsgs_comp);
+}
+
+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);
+ break;
+ case MINOR_FLUSH:
+ ret = aoedev_flush(buf, cnt);
+ break;
+ }
+ if (ret == 0)
+ ret = cnt;
+ return ret;
+}
+
+static int
+aoechr_open(struct inode *inode, struct file *filp)
+{
+ int n, i;
+
+ mutex_lock(&aoechr_mutex);
+ n = iminor(inode);
+ filp->private_data = (void *) (unsigned long) n;
+
+ for (i = 0; i < ARRAY_SIZE(chardevs); ++i)
+ if (chardevs[i].minor == n) {
+ mutex_unlock(&aoechr_mutex);
+ return 0;
+ }
+ mutex_unlock(&aoechr_mutex);
+ 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;
+ if (n != MINOR_ERR)
+ return -EFAULT;
+
+ spin_lock_irqsave(&emsgs_lock, flags);
+
+ for (;;) {
+ em = emsgs + emsgs_head_idx;
+ if ((em->flags & EMFL_VALID) != 0)
+ break;
+ if (filp->f_flags & O_NDELAY) {
+ spin_unlock_irqrestore(&emsgs_lock, flags);
+ return -EAGAIN;
+ }
+ nblocked_emsgs_readers++;
+
+ spin_unlock_irqrestore(&emsgs_lock, flags);
+
+ n = wait_for_completion_interruptible(&emsgs_comp);
+
+ spin_lock_irqsave(&emsgs_lock, flags);
+
+ nblocked_emsgs_readers--;
+
+ if (n) {
+ spin_unlock_irqrestore(&emsgs_lock, flags);
+ return -ERESTARTSYS;
+ }
+ }
+ 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;
+}
+
+static const struct file_operations aoe_fops = {
+ .write = aoechr_write,
+ .read = aoechr_read,
+ .open = aoechr_open,
+ .release = aoechr_rel,
+ .owner = THIS_MODULE,
+ .llseek = noop_llseek,
+};
+
+static char *aoe_devnode(struct device *dev, umode_t *mode)
+{
+ return kasprintf(GFP_KERNEL, "etherd/%s", dev_name(dev));
+}
+
+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;
+ }
+ init_completion(&emsgs_comp);
+ 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);
+ }
+ aoe_class->devnode = aoe_devnode;
+
+ for (i = 0; i < ARRAY_SIZE(chardevs); ++i)
+ 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)
+ device_destroy(aoe_class, MKDEV(AOE_MAJOR, chardevs[i].minor));
+ class_destroy(aoe_class);
+ unregister_chrdev(AOE_MAJOR, "aoechr");
+}
+
Code Review / kvmfornfv.git / blobdiff