321 lines
6.2 KiB
C
Executable File
321 lines
6.2 KiB
C
Executable File
/* Copyright (c) 2012 Coraid, Inc. See COPYING for GPL terms. */
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/*
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* aoechr.c
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* AoE character device driver
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*/
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#include <linux/hdreg.h>
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#include <linux/blkdev.h>
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#include <linux/completion.h>
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#include <linux/delay.h>
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#include <linux/slab.h>
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#include <linux/mutex.h>
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#include <linux/skbuff.h>
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#include <linux/export.h>
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#include "aoe.h"
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enum {
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//MINOR_STAT = 1, (moved to sysfs)
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MINOR_ERR = 2,
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MINOR_DISCOVER,
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MINOR_INTERFACES,
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MINOR_REVALIDATE,
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MINOR_FLUSH,
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MSGSZ = 2048,
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NMSG = 100, /* message backlog to retain */
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};
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struct aoe_chardev {
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ulong minor;
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char name[32];
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};
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enum { EMFL_VALID = 1 };
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struct ErrMsg {
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short flags;
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short len;
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char *msg;
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};
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static DEFINE_MUTEX(aoechr_mutex);
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/* A ring buffer of error messages, to be read through
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* "/dev/etherd/err". When no messages are present,
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* readers will block waiting for messages to appear.
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*/
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static struct ErrMsg emsgs[NMSG];
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static int emsgs_head_idx, emsgs_tail_idx;
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static struct completion emsgs_comp;
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static spinlock_t emsgs_lock;
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static int nblocked_emsgs_readers;
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static struct class *aoe_class;
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static struct aoe_chardev chardevs[] = {
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{ MINOR_ERR, "err" },
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{ MINOR_DISCOVER, "discover" },
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{ MINOR_INTERFACES, "interfaces" },
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{ MINOR_REVALIDATE, "revalidate" },
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{ MINOR_FLUSH, "flush" },
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};
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static int
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discover(void)
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{
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aoecmd_cfg(0xffff, 0xff);
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return 0;
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}
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static int
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interfaces(const char __user *str, size_t size)
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{
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if (set_aoe_iflist(str, size)) {
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printk(KERN_ERR
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"aoe: could not set interface list: too many interfaces\n");
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return -EINVAL;
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}
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return 0;
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}
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static int
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revalidate(const char __user *str, size_t size)
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{
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int major, minor, n;
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ulong flags;
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struct aoedev *d;
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struct sk_buff *skb;
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char buf[16];
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if (size >= sizeof buf)
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return -EINVAL;
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buf[sizeof buf - 1] = '\0';
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if (copy_from_user(buf, str, size))
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return -EFAULT;
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n = sscanf(buf, "e%d.%d", &major, &minor);
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if (n != 2) {
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pr_err("aoe: invalid device specification %s\n", buf);
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return -EINVAL;
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}
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d = aoedev_by_aoeaddr(major, minor, 0);
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if (!d)
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return -EINVAL;
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spin_lock_irqsave(&d->lock, flags);
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aoecmd_cleanslate(d);
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aoecmd_cfg(major, minor);
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loop:
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skb = aoecmd_ata_id(d);
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spin_unlock_irqrestore(&d->lock, flags);
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/* try again if we are able to sleep a bit,
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* otherwise give up this revalidation
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*/
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if (!skb && !msleep_interruptible(250)) {
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spin_lock_irqsave(&d->lock, flags);
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goto loop;
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}
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aoedev_put(d);
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if (skb) {
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struct sk_buff_head queue;
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__skb_queue_head_init(&queue);
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__skb_queue_tail(&queue, skb);
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aoenet_xmit(&queue);
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}
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return 0;
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}
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void
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aoechr_error(char *msg)
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{
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struct ErrMsg *em;
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char *mp;
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ulong flags, n;
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n = strlen(msg);
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spin_lock_irqsave(&emsgs_lock, flags);
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em = emsgs + emsgs_tail_idx;
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if ((em->flags & EMFL_VALID)) {
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bail: spin_unlock_irqrestore(&emsgs_lock, flags);
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return;
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}
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mp = kmemdup(msg, n, GFP_ATOMIC);
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if (mp == NULL) {
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printk(KERN_ERR "aoe: allocation failure, len=%ld\n", n);
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goto bail;
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}
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em->msg = mp;
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em->flags |= EMFL_VALID;
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em->len = n;
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emsgs_tail_idx++;
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emsgs_tail_idx %= ARRAY_SIZE(emsgs);
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spin_unlock_irqrestore(&emsgs_lock, flags);
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if (nblocked_emsgs_readers)
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complete(&emsgs_comp);
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}
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static ssize_t
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aoechr_write(struct file *filp, const char __user *buf, size_t cnt, loff_t *offp)
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{
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int ret = -EINVAL;
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switch ((unsigned long) filp->private_data) {
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default:
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printk(KERN_INFO "aoe: can't write to that file.\n");
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break;
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case MINOR_DISCOVER:
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ret = discover();
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break;
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case MINOR_INTERFACES:
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ret = interfaces(buf, cnt);
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break;
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case MINOR_REVALIDATE:
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ret = revalidate(buf, cnt);
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break;
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case MINOR_FLUSH:
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ret = aoedev_flush(buf, cnt);
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break;
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}
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if (ret == 0)
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ret = cnt;
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return ret;
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}
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static int
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aoechr_open(struct inode *inode, struct file *filp)
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{
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int n, i;
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mutex_lock(&aoechr_mutex);
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n = iminor(inode);
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filp->private_data = (void *) (unsigned long) n;
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for (i = 0; i < ARRAY_SIZE(chardevs); ++i)
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if (chardevs[i].minor == n) {
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mutex_unlock(&aoechr_mutex);
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return 0;
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}
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mutex_unlock(&aoechr_mutex);
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return -EINVAL;
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}
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static int
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aoechr_rel(struct inode *inode, struct file *filp)
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{
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return 0;
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}
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static ssize_t
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aoechr_read(struct file *filp, char __user *buf, size_t cnt, loff_t *off)
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{
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unsigned long n;
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char *mp;
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struct ErrMsg *em;
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ssize_t len;
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ulong flags;
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n = (unsigned long) filp->private_data;
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if (n != MINOR_ERR)
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return -EFAULT;
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spin_lock_irqsave(&emsgs_lock, flags);
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for (;;) {
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em = emsgs + emsgs_head_idx;
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if ((em->flags & EMFL_VALID) != 0)
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break;
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if (filp->f_flags & O_NDELAY) {
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spin_unlock_irqrestore(&emsgs_lock, flags);
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return -EAGAIN;
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}
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nblocked_emsgs_readers++;
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spin_unlock_irqrestore(&emsgs_lock, flags);
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n = wait_for_completion_interruptible(&emsgs_comp);
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spin_lock_irqsave(&emsgs_lock, flags);
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nblocked_emsgs_readers--;
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if (n) {
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spin_unlock_irqrestore(&emsgs_lock, flags);
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return -ERESTARTSYS;
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}
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}
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if (em->len > cnt) {
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spin_unlock_irqrestore(&emsgs_lock, flags);
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return -EAGAIN;
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}
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mp = em->msg;
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len = em->len;
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em->msg = NULL;
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em->flags &= ~EMFL_VALID;
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emsgs_head_idx++;
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emsgs_head_idx %= ARRAY_SIZE(emsgs);
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spin_unlock_irqrestore(&emsgs_lock, flags);
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n = copy_to_user(buf, mp, len);
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kfree(mp);
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return n == 0 ? len : -EFAULT;
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}
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static const struct file_operations aoe_fops = {
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.write = aoechr_write,
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.read = aoechr_read,
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.open = aoechr_open,
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.release = aoechr_rel,
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.owner = THIS_MODULE,
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.llseek = noop_llseek,
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};
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static char *aoe_devnode(struct device *dev, umode_t *mode)
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{
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return kasprintf(GFP_KERNEL, "etherd/%s", dev_name(dev));
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}
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int __init
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aoechr_init(void)
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{
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int n, i;
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n = register_chrdev(AOE_MAJOR, "aoechr", &aoe_fops);
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if (n < 0) {
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printk(KERN_ERR "aoe: can't register char device\n");
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return n;
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}
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init_completion(&emsgs_comp);
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spin_lock_init(&emsgs_lock);
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aoe_class = class_create(THIS_MODULE, "aoe");
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if (IS_ERR(aoe_class)) {
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unregister_chrdev(AOE_MAJOR, "aoechr");
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return PTR_ERR(aoe_class);
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}
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aoe_class->devnode = aoe_devnode;
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for (i = 0; i < ARRAY_SIZE(chardevs); ++i)
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device_create(aoe_class, NULL,
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MKDEV(AOE_MAJOR, chardevs[i].minor), NULL,
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chardevs[i].name);
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return 0;
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}
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void
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aoechr_exit(void)
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{
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int i;
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for (i = 0; i < ARRAY_SIZE(chardevs); ++i)
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device_destroy(aoe_class, MKDEV(AOE_MAJOR, chardevs[i].minor));
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class_destroy(aoe_class);
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unregister_chrdev(AOE_MAJOR, "aoechr");
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}
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