linux/drivers/block/aoe/aoedev.c

421 lines
8.6 KiB
C

/* Copyright (c) 2012 Coraid, Inc. See COPYING for GPL terms. */
/*
* aoedev.c
* AoE device utility functions; maintains device list.
*/
#include <linux/hdreg.h>
#include <linux/blkdev.h>
#include <linux/netdevice.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/bitmap.h>
#include <linux/kdev_t.h>
#include <linux/moduleparam.h>
#include "aoe.h"
static void dummy_timer(ulong);
static void aoedev_freedev(struct aoedev *);
static void freetgt(struct aoedev *d, struct aoetgt *t);
static void skbpoolfree(struct aoedev *d);
static int aoe_dyndevs = 1;
module_param(aoe_dyndevs, int, 0644);
MODULE_PARM_DESC(aoe_dyndevs, "Use dynamic minor numbers for devices.");
static struct aoedev *devlist;
static DEFINE_SPINLOCK(devlist_lock);
/* Because some systems will have one, many, or no
* - partitions,
* - slots per shelf,
* - or shelves,
* we need some flexibility in the way the minor numbers
* are allocated. So they are dynamic.
*/
#define N_DEVS ((1U<<MINORBITS)/AOE_PARTITIONS)
static DEFINE_SPINLOCK(used_minors_lock);
static DECLARE_BITMAP(used_minors, N_DEVS);
static int
minor_get_dyn(ulong *sysminor)
{
ulong flags;
ulong n;
int error = 0;
spin_lock_irqsave(&used_minors_lock, flags);
n = find_first_zero_bit(used_minors, N_DEVS);
if (n < N_DEVS)
set_bit(n, used_minors);
else
error = -1;
spin_unlock_irqrestore(&used_minors_lock, flags);
*sysminor = n * AOE_PARTITIONS;
return error;
}
static int
minor_get_static(ulong *sysminor, ulong aoemaj, int aoemin)
{
ulong flags;
ulong n;
int error = 0;
enum {
/* for backwards compatibility when !aoe_dyndevs,
* a static number of supported slots per shelf */
NPERSHELF = 16,
};
n = aoemaj * NPERSHELF + aoemin;
if (aoemin >= NPERSHELF || n >= N_DEVS) {
pr_err("aoe: %s with e%ld.%d\n",
"cannot use static minor device numbers",
aoemaj, aoemin);
error = -1;
} else {
spin_lock_irqsave(&used_minors_lock, flags);
if (test_bit(n, used_minors)) {
pr_err("aoe: %s %lu\n",
"existing device already has static minor number",
n);
error = -1;
} else
set_bit(n, used_minors);
spin_unlock_irqrestore(&used_minors_lock, flags);
}
*sysminor = n;
return error;
}
static int
minor_get(ulong *sysminor, ulong aoemaj, int aoemin)
{
if (aoe_dyndevs)
return minor_get_dyn(sysminor);
else
return minor_get_static(sysminor, aoemaj, aoemin);
}
static void
minor_free(ulong minor)
{
ulong flags;
minor /= AOE_PARTITIONS;
BUG_ON(minor >= N_DEVS);
spin_lock_irqsave(&used_minors_lock, flags);
BUG_ON(!test_bit(minor, used_minors));
clear_bit(minor, used_minors);
spin_unlock_irqrestore(&used_minors_lock, flags);
}
/*
* Users who grab a pointer to the device with aoedev_by_aoeaddr
* automatically get a reference count and must be responsible
* for performing a aoedev_put. With the addition of async
* kthread processing I'm no longer confident that we can
* guarantee consistency in the face of device flushes.
*
* For the time being, we only bother to add extra references for
* frames sitting on the iocq. When the kthreads finish processing
* these frames, they will aoedev_put the device.
*/
void
aoedev_put(struct aoedev *d)
{
ulong flags;
spin_lock_irqsave(&devlist_lock, flags);
d->ref--;
spin_unlock_irqrestore(&devlist_lock, flags);
}
static void
dummy_timer(ulong vp)
{
struct aoedev *d;
d = (struct aoedev *)vp;
if (d->flags & DEVFL_TKILL)
return;
d->timer.expires = jiffies + HZ;
add_timer(&d->timer);
}
static void
aoe_failip(struct aoedev *d)
{
struct request *rq;
struct bio *bio;
unsigned long n;
aoe_failbuf(d, d->ip.buf);
rq = d->ip.rq;
if (rq == NULL)
return;
while ((bio = d->ip.nxbio)) {
clear_bit(BIO_UPTODATE, &bio->bi_flags);
d->ip.nxbio = bio->bi_next;
n = (unsigned long) rq->special;
rq->special = (void *) --n;
}
if ((unsigned long) rq->special == 0)
aoe_end_request(d, rq, 0);
}
void
aoedev_downdev(struct aoedev *d)
{
struct aoetgt *t, **tt, **te;
struct frame *f;
struct list_head *head, *pos, *nx;
struct request *rq;
int i;
d->flags &= ~DEVFL_UP;
/* clean out active buffers */
for (i = 0; i < NFACTIVE; i++) {
head = &d->factive[i];
list_for_each_safe(pos, nx, head) {
f = list_entry(pos, struct frame, head);
list_del(pos);
if (f->buf) {
f->buf->nframesout--;
aoe_failbuf(d, f->buf);
}
aoe_freetframe(f);
}
}
/* reset window dressings */
tt = d->targets;
te = tt + NTARGETS;
for (; tt < te && (t = *tt); tt++) {
t->maxout = t->nframes;
t->nout = 0;
}
/* clean out the in-process request (if any) */
aoe_failip(d);
d->htgt = NULL;
/* fast fail all pending I/O */
if (d->blkq) {
while ((rq = blk_peek_request(d->blkq))) {
blk_start_request(rq);
aoe_end_request(d, rq, 1);
}
}
if (d->gd)
set_capacity(d->gd, 0);
}
static void
aoedev_freedev(struct aoedev *d)
{
struct aoetgt **t, **e;
cancel_work_sync(&d->work);
if (d->gd) {
aoedisk_rm_sysfs(d);
del_gendisk(d->gd);
put_disk(d->gd);
blk_cleanup_queue(d->blkq);
}
t = d->targets;
e = t + NTARGETS;
for (; t < e && *t; t++)
freetgt(d, *t);
if (d->bufpool)
mempool_destroy(d->bufpool);
skbpoolfree(d);
minor_free(d->sysminor);
kfree(d);
}
int
aoedev_flush(const char __user *str, size_t cnt)
{
ulong flags;
struct aoedev *d, **dd;
struct aoedev *rmd = NULL;
char buf[16];
int all = 0;
if (cnt >= 3) {
if (cnt > sizeof buf)
cnt = sizeof buf;
if (copy_from_user(buf, str, cnt))
return -EFAULT;
all = !strncmp(buf, "all", 3);
}
spin_lock_irqsave(&devlist_lock, flags);
dd = &devlist;
while ((d = *dd)) {
spin_lock(&d->lock);
if ((!all && (d->flags & DEVFL_UP))
|| (d->flags & (DEVFL_GDALLOC|DEVFL_NEWSIZE))
|| d->nopen
|| d->ref) {
spin_unlock(&d->lock);
dd = &d->next;
continue;
}
*dd = d->next;
aoedev_downdev(d);
d->flags |= DEVFL_TKILL;
spin_unlock(&d->lock);
d->next = rmd;
rmd = d;
}
spin_unlock_irqrestore(&devlist_lock, flags);
while ((d = rmd)) {
rmd = d->next;
del_timer_sync(&d->timer);
aoedev_freedev(d); /* must be able to sleep */
}
return 0;
}
/* This has been confirmed to occur once with Tms=3*1000 due to the
* driver changing link and not processing its transmit ring. The
* problem is hard enough to solve by returning an error that I'm
* still punting on "solving" this.
*/
static void
skbfree(struct sk_buff *skb)
{
enum { Sms = 250, Tms = 30 * 1000};
int i = Tms / Sms;
if (skb == NULL)
return;
while (atomic_read(&skb_shinfo(skb)->dataref) != 1 && i-- > 0)
msleep(Sms);
if (i < 0) {
printk(KERN_ERR
"aoe: %s holds ref: %s\n",
skb->dev ? skb->dev->name : "netif",
"cannot free skb -- memory leaked.");
return;
}
skb->truesize -= skb->data_len;
skb_shinfo(skb)->nr_frags = skb->data_len = 0;
skb_trim(skb, 0);
dev_kfree_skb(skb);
}
static void
skbpoolfree(struct aoedev *d)
{
struct sk_buff *skb, *tmp;
skb_queue_walk_safe(&d->skbpool, skb, tmp)
skbfree(skb);
__skb_queue_head_init(&d->skbpool);
}
/* find it or allocate it */
struct aoedev *
aoedev_by_aoeaddr(ulong maj, int min, int do_alloc)
{
struct aoedev *d;
int i;
ulong flags;
ulong sysminor;
spin_lock_irqsave(&devlist_lock, flags);
for (d=devlist; d; d=d->next)
if (d->aoemajor == maj && d->aoeminor == min) {
d->ref++;
break;
}
if (d || !do_alloc || minor_get(&sysminor, maj, min) < 0)
goto out;
d = kcalloc(1, sizeof *d, GFP_ATOMIC);
if (!d)
goto out;
INIT_WORK(&d->work, aoecmd_sleepwork);
spin_lock_init(&d->lock);
skb_queue_head_init(&d->skbpool);
init_timer(&d->timer);
d->timer.data = (ulong) d;
d->timer.function = dummy_timer;
d->timer.expires = jiffies + HZ;
add_timer(&d->timer);
d->bufpool = NULL; /* defer to aoeblk_gdalloc */
d->tgt = d->targets;
d->ref = 1;
for (i = 0; i < NFACTIVE; i++)
INIT_LIST_HEAD(&d->factive[i]);
d->sysminor = sysminor;
d->aoemajor = maj;
d->aoeminor = min;
d->mintimer = MINTIMER;
d->next = devlist;
devlist = d;
out:
spin_unlock_irqrestore(&devlist_lock, flags);
return d;
}
static void
freetgt(struct aoedev *d, struct aoetgt *t)
{
struct frame *f;
struct list_head *pos, *nx, *head;
struct aoeif *ifp;
for (ifp = t->ifs; ifp < &t->ifs[NAOEIFS]; ++ifp) {
if (!ifp->nd)
break;
dev_put(ifp->nd);
}
head = &t->ffree;
list_for_each_safe(pos, nx, head) {
list_del(pos);
f = list_entry(pos, struct frame, head);
skbfree(f->skb);
kfree(f);
}
kfree(t);
}
void
aoedev_exit(void)
{
struct aoedev *d;
ulong flags;
aoe_flush_iocq();
while ((d = devlist)) {
devlist = d->next;
spin_lock_irqsave(&d->lock, flags);
aoedev_downdev(d);
d->flags |= DEVFL_TKILL;
spin_unlock_irqrestore(&d->lock, flags);
del_timer_sync(&d->timer);
aoedev_freedev(d);
}
}
int __init
aoedev_init(void)
{
return 0;
}