release/src-rt-6.x.4708/linux/linux-2.6.36/drivers/block/aoe/aoedev.c

   1 /* Copyright (c) 2007 Coraid, Inc.  See COPYING for GPL terms. */
   2 /*
   3  * aoedev.c
   4  * AoE device utility functions; maintains device list.
   5  */
   6
   7 #include <linux/hdreg.h>
   8 #include <linux/blkdev.h>
   9 #include <linux/netdevice.h>
  10 #include <linux/delay.h>
  11 #include <linux/slab.h>
  12 #include "aoe.h"
  13
  14 static void dummy_timer(ulong);
  15 static void aoedev_freedev(struct aoedev *);
  16 static void freetgt(struct aoedev *d, struct aoetgt *t);
  17 static void skbpoolfree(struct aoedev *d);
  18
  19 static struct aoedev *devlist;
  20 static DEFINE_SPINLOCK(devlist_lock);
  21
  22 struct aoedev *
  23 aoedev_by_aoeaddr(int maj, int min)
  24 {
  25         struct aoedev *d;
  26         ulong flags;
  27
  28         spin_lock_irqsave(&devlist_lock, flags);
  29
  30         for (d=devlist; d; d=d->next)
  31                 if (d->aoemajor == maj && d->aoeminor == min)
  32                         break;
  33
  34         spin_unlock_irqrestore(&devlist_lock, flags);
  35         return d;
  36 }
  37
  38 static void
  39 dummy_timer(ulong vp)
  40 {
  41         struct aoedev *d;
  42
  43         d = (struct aoedev *)vp;
  44         if (d->flags & DEVFL_TKILL)
  45                 return;
  46         d->timer.expires = jiffies + HZ;
  47         add_timer(&d->timer);
  48 }
  49
  50 void
  51 aoedev_downdev(struct aoedev *d)
  52 {
  53         struct aoetgt **t, **te;
  54         struct frame *f, *e;
  55         struct buf *buf;
  56         struct bio *bio;
  57
  58         t = d->targets;
  59         te = t + NTARGETS;
  60         for (; t < te && *t; t++) {
  61                 f = (*t)->frames;
  62                 e = f + (*t)->nframes;
  63                 for (; f < e; f->tag = FREETAG, f->buf = NULL, f++) {
  64                         if (f->tag == FREETAG || f->buf == NULL)
  65                                 continue;
  66                         buf = f->buf;
  67                         bio = buf->bio;
  68                         if (--buf->nframesout == 0
  69                         && buf != d->inprocess) {
  70                                 mempool_free(buf, d->bufpool);
  71                                 bio_endio(bio, -EIO);
  72                         }
  73                 }
  74                 (*t)->maxout = (*t)->nframes;
  75                 (*t)->nout = 0;
  76         }
  77         buf = d->inprocess;
  78         if (buf) {
  79                 bio = buf->bio;
  80                 mempool_free(buf, d->bufpool);
  81                 bio_endio(bio, -EIO);
  82         }
  83         d->inprocess = NULL;
  84         d->htgt = NULL;
  85
  86         while (!list_empty(&d->bufq)) {
  87                 buf = container_of(d->bufq.next, struct buf, bufs);
  88                 list_del(d->bufq.next);
  89                 bio = buf->bio;
  90                 mempool_free(buf, d->bufpool);
  91                 bio_endio(bio, -EIO);
  92         }
  93
  94         if (d->gd)
  95                 set_capacity(d->gd, 0);
  96
  97         d->flags &= ~DEVFL_UP;
  98 }
  99
 100 static void
 101 aoedev_freedev(struct aoedev *d)
 102 {
 103         struct aoetgt **t, **e;
 104
 105         if (d->gd) {
 106                 aoedisk_rm_sysfs(d);
 107                 del_gendisk(d->gd);
 108                 put_disk(d->gd);
 109         }
 110         t = d->targets;
 111         e = t + NTARGETS;
 112         for (; t < e && *t; t++)
 113                 freetgt(d, *t);
 114         if (d->bufpool)
 115                 mempool_destroy(d->bufpool);
 116         skbpoolfree(d);
 117         blk_cleanup_queue(d->blkq);
 118         kfree(d);
 119 }
 120
 121 int
 122 aoedev_flush(const char __user *str, size_t cnt)
 123 {
 124         ulong flags;
 125         struct aoedev *d, **dd;
 126         struct aoedev *rmd = NULL;
 127         char buf[16];
 128         int all = 0;
 129
 130         if (cnt >= 3) {
 131                 if (cnt > sizeof buf)
 132                         cnt = sizeof buf;
 133                 if (copy_from_user(buf, str, cnt))
 134                         return -EFAULT;
 135                 all = !strncmp(buf, "all", 3);
 136         }
 137
 138         flush_scheduled_work();
 139         spin_lock_irqsave(&devlist_lock, flags);
 140         dd = &devlist;
 141         while ((d = *dd)) {
 142                 spin_lock(&d->lock);
 143                 if ((!all && (d->flags & DEVFL_UP))
 144                 || (d->flags & (DEVFL_GDALLOC|DEVFL_NEWSIZE))
 145                 || d->nopen) {
 146                         spin_unlock(&d->lock);
 147                         dd = &d->next;
 148                         continue;
 149                 }
 150                 *dd = d->next;
 151                 aoedev_downdev(d);
 152                 d->flags |= DEVFL_TKILL;
 153                 spin_unlock(&d->lock);
 154                 d->next = rmd;
 155                 rmd = d;
 156         }
 157         spin_unlock_irqrestore(&devlist_lock, flags);
 158         while ((d = rmd)) {
 159                 rmd = d->next;
 160                 del_timer_sync(&d->timer);
 161                 aoedev_freedev(d);      /* must be able to sleep */
 162         }
 163         return 0;
 164 }
 165
 166 /* I'm not really sure that this is a realistic problem, but if the
 167 network driver goes gonzo let's just leak memory after complaining. */
 168 static void
 169 skbfree(struct sk_buff *skb)
 170 {
 171         enum { Sms = 100, Tms = 3*1000};
 172         int i = Tms / Sms;
 173
 174         if (skb == NULL)
 175                 return;
 176         while (atomic_read(&skb_shinfo(skb)->dataref) != 1 && i-- > 0)
 177                 msleep(Sms);
 178         if (i < 0) {
 179                 printk(KERN_ERR
 180                         "aoe: %s holds ref: %s\n",
 181                         skb->dev ? skb->dev->name : "netif",
 182                         "cannot free skb -- memory leaked.");
 183                 return;
 184         }
 185         skb_shinfo(skb)->nr_frags = skb->data_len = 0;
 186         skb_trim(skb, 0);
 187         dev_kfree_skb(skb);
 188 }
 189
 190 static void
 191 skbpoolfree(struct aoedev *d)
 192 {
 193         struct sk_buff *skb, *tmp;
 194
 195         skb_queue_walk_safe(&d->skbpool, skb, tmp)
 196                 skbfree(skb);
 197
 198         __skb_queue_head_init(&d->skbpool);
 199 }
 200
 201 /* find it or malloc it */
 202 struct aoedev *
 203 aoedev_by_sysminor_m(ulong sysminor)
 204 {
 205         struct aoedev *d;
 206         ulong flags;
 207
 208         spin_lock_irqsave(&devlist_lock, flags);
 209
 210         for (d=devlist; d; d=d->next)
 211                 if (d->sysminor == sysminor)
 212                         break;
 213         if (d)
 214                 goto out;
 215         d = kcalloc(1, sizeof *d, GFP_ATOMIC);
 216         if (!d)
 217                 goto out;
 218         INIT_WORK(&d->work, aoecmd_sleepwork);
 219         spin_lock_init(&d->lock);
 220         skb_queue_head_init(&d->sendq);
 221         skb_queue_head_init(&d->skbpool);
 222         init_timer(&d->timer);
 223         d->timer.data = (ulong) d;
 224         d->timer.function = dummy_timer;
 225         d->timer.expires = jiffies + HZ;
 226         add_timer(&d->timer);
 227         d->bufpool = NULL;      /* defer to aoeblk_gdalloc */
 228         d->tgt = d->targets;
 229         INIT_LIST_HEAD(&d->bufq);
 230         d->sysminor = sysminor;
 231         d->aoemajor = AOEMAJOR(sysminor);
 232         d->aoeminor = AOEMINOR(sysminor);
 233         d->mintimer = MINTIMER;
 234         d->next = devlist;
 235         devlist = d;
 236  out:
 237         spin_unlock_irqrestore(&devlist_lock, flags);
 238         return d;
 239 }
 240
 241 static void
 242 freetgt(struct aoedev *d, struct aoetgt *t)
 243 {
 244         struct frame *f, *e;
 245
 246         f = t->frames;
 247         e = f + t->nframes;
 248         for (; f < e; f++)
 249                 skbfree(f->skb);
 250         kfree(t->frames);
 251         kfree(t);
 252 }
 253
 254 void
 255 aoedev_exit(void)
 256 {
 257         struct aoedev *d;
 258         ulong flags;
 259
 260         flush_scheduled_work();
 261
 262         while ((d = devlist)) {
 263                 devlist = d->next;
 264
 265                 spin_lock_irqsave(&d->lock, flags);
 266                 aoedev_downdev(d);
 267                 d->flags |= DEVFL_TKILL;
 268                 spin_unlock_irqrestore(&d->lock, flags);
 269
 270                 del_timer_sync(&d->timer);
 271                 aoedev_freedev(d);
 272         }
 273 }
 274
 275 int __init
 276 aoedev_init(void)
 277 {
 278         return 0;
 279 }