android_kernel_xiaomi_sm8350/drivers/block/aoe/aoechr.c
Ed L. Cashin 3ae1c24e39 [PATCH] aoe [2/8]: support dynamic resizing of AoE devices
Allow the driver to recognize AoE devices that have changed size.
Devices not in use are updated automatically, and devices that are in
use are updated at user request.

Signed-off-by: "Ed L. Cashin" <ecashin@coraid.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-03-23 22:01:55 -08:00

282 lines
5.3 KiB
C

/* 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,
MINOR_REVALIDATE,
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 *aoe_class;
static struct aoe_chardev chardevs[] = {
{ MINOR_ERR, "err" },
{ MINOR_DISCOVER, "discover" },
{ MINOR_INTERFACES, "interfaces" },
{ MINOR_REVALIDATE, "revalidate" },
};
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;
}
static int
revalidate(const char __user *str, size_t size)
{
int major, minor, n;
ulong flags;
struct aoedev *d;
char buf[16];
if (size >= sizeof buf)
return -EINVAL;
buf[sizeof buf - 1] = '\0';
if (copy_from_user(buf, str, size))
return -EFAULT;
/* should be e%d.%d format */
n = sscanf(buf, "e%d.%d", &major, &minor);
if (n != 2) {
printk(KERN_ERR "aoe: %s: invalid device specification\n",
__FUNCTION__);
return -EINVAL;
}
d = aoedev_by_aoeaddr(major, minor);
if (!d)
return -EINVAL;
spin_lock_irqsave(&d->lock, flags);
d->flags |= DEVFL_PAUSE;
spin_unlock_irqrestore(&d->lock, flags);
aoecmd_cfg(major, minor);
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;
case MINOR_REVALIDATE:
ret = revalidate(buf, cnt);
}
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_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_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)
class_device_destroy(aoe_class, MKDEV(AOE_MAJOR, chardevs[i].minor));
class_destroy(aoe_class);
unregister_chrdev(AOE_MAJOR, "aoechr");
}