lustre/kernel_patches/patches/dynamic-locks-2.4.24.patch

   1  include/linux/dynlocks.h |   33 ++++++++++
   2  lib/Makefile             |    4 -
   3  lib/dynlocks.c           |  152 +++++++++++++++++++++++++++++++++++++++++++++++
   4  3 files changed, 187 insertions(+), 2 deletions(-)
   5
   6 Index: linux-2.4.24/include/linux/dynlocks.h
   7 ===================================================================
   8 --- linux-2.4.24.orig/include/linux/dynlocks.h  2003-01-30 13:24:37.000000000 +0300
   9 +++ linux-2.4.24/include/linux/dynlocks.h       2004-07-16 10:25:15.000000000 +0400
  10 @@ -0,0 +1,45 @@
  11 +#ifndef _LINUX_DYNLOCKS_H
  12 +#define _LINUX_DYNLOCKS_H
  13 +
  14 +#include <linux/list.h>
  15 +#include <linux/wait.h>
  16 +
  17 +#define DYNLOCK_MAGIC          0xd19a10c
  18 +#define DYNLOCK_MAGIC2         0xd1956ee
  19 +
  20 +struct dynlock;
  21 +
  22 +struct dynlock_member {
  23 +       unsigned                dl_magic;
  24 +       struct list_head        dl_list;
  25 +       unsigned long           dl_value;       /* lock value */
  26 +       int                     dl_refcount;    /* number of users */
  27 +       int                     dl_readers;
  28 +       int                     dl_writers;
  29 +       int                     dl_pid;         /* holder of the lock */
  30 +       wait_queue_head_t       dl_wait;
  31 +       struct dynlock          *dl_head;
  32 +};
  33 +
  34 +/*
  35 + * lock's namespace:
  36 + *   - list of locks
  37 + *   - lock to protect this list
  38 + */
  39 +
  40 +#define DYNLOCK_LIST_MAGIC     0x11ee91e6
  41 +
  42 +struct dynlock {
  43 +       unsigned dl_magic;
  44 +       struct list_head dl_list;
  45 +       spinlock_t dl_list_lock;
  46 +       struct dynlock * dl_back;
  47 +};
  48 +
  49 +void dynlock_init(struct dynlock *dl);
  50 +void *dynlock_lock(struct dynlock *dl, unsigned long value, int rw, int gfp);
  51 +void dynlock_unlock(struct dynlock *dl, void *lock);
  52 +
  53 +
  54 +#endif
  55 +
  56 Index: linux-2.4.24/lib/dynlocks.c
  57 ===================================================================
  58 --- linux-2.4.24.orig/lib/dynlocks.c    2003-01-30 13:24:37.000000000 +0300
  59 +++ linux-2.4.24/lib/dynlocks.c 2004-07-16 11:53:38.000000000 +0400
  60 @@ -0,0 +1,199 @@
  61 +/*
  62 + * Dynamic Locks
  63 + *
  64 + * struct dynlock is lockspace
  65 + * one may request lock (exclusive or shared) for some value
  66 + * in that lockspace
  67 + *
  68 + */
  69 +
  70 +#include <linux/dynlocks.h>
  71 +#include <linux/module.h>
  72 +#include <linux/slab.h>
  73 +#include <linux/sched.h>
  74 +
  75 +/*
  76 + * dynlock_init
  77 + *
  78 + * initialize lockspace
  79 + *
  80 + */
  81 +void dynlock_init(struct dynlock *dl)
  82 +{
  83 +       spin_lock_init(&dl->dl_list_lock);
  84 +       INIT_LIST_HEAD(&dl->dl_list);
  85 +       dl->dl_magic = DYNLOCK_LIST_MAGIC;
  86 +       dl->dl_back = dl;
  87 +}
  88 +
  89 +/*
  90 + * dynlock_lock
  91 + *
  92 + * acquires lock (exclusive or shared) in specified lockspace
  93 + * each lock in lockspace is allocated separately, so user have
  94 + * to specify GFP flags.
  95 + * routine returns pointer to lock. this pointer is intended to
  96 + * be passed to dynlock_unlock
  97 + *
  98 + */
  99 +void *dynlock_lock(struct dynlock *dl, unsigned long value, int rw, int gfp)
 100 +{
 101 +       struct dynlock_member *nhl = NULL;
 102 +       struct dynlock_member *hl;
 103 +       struct list_head *cur;
 104 +       int num = 0;
 105 +
 106 +       BUG_ON(dl == NULL);
 107 +       if (dl->dl_magic != DYNLOCK_LIST_MAGIC) {
 108 +               printk("corrupted dynlock head 0x%p: magic 0x%x (!=0x%x)\n",
 109 +                       dl, dl->dl_magic, DYNLOCK_LIST_MAGIC);
 110 +               BUG();
 111 +       }
 112 +       BUG_ON(dl->dl_back != dl);
 113 +repeat:
 114 +       /* find requested lock in lockspace */
 115 +       spin_lock(&dl->dl_list_lock);
 116 +       BUG_ON(dl->dl_list.next == NULL);
 117 +       BUG_ON(dl->dl_list.prev == NULL);
 118 +       list_for_each(cur, &dl->dl_list) {
 119 +               BUG_ON(cur->next == NULL);
 120 +               BUG_ON(cur->prev == NULL);
 121 +               hl = list_entry(cur, struct dynlock_member, dl_list);
 122 +               if (hl->dl_magic != DYNLOCK_MAGIC || hl->dl_head != dl) {
 123 +                       printk("corrupted lock 0x%p/%d: magic 0x%x (!=0x%x)\n",
 124 +                               hl, num, hl->dl_magic, DYNLOCK_MAGIC);
 125 +                       printk("  value 0x%lx, %d readers, %d writers, pid %d, %d refs\n",
 126 +                               hl->dl_value, hl->dl_readers, hl->dl_writers,
 127 +                               hl->dl_pid, hl->dl_refcount);
 128 +                       printk("   head 0x%p\n", hl->dl_head);
 129 +                       BUG();
 130 +               }
 131 +               if (hl->dl_value == value) {
 132 +                       /* lock is found */
 133 +                       if (nhl) {
 134 +                               /* someone else just allocated
 135 +                                * lock we didn't find and just created
 136 +                                * so, we drop our lock
 137 +                                */
 138 +                               kfree(nhl);
 139 +                               nhl = NULL;
 140 +                       }
 141 +                       hl->dl_refcount++;
 142 +                       goto found;
 143 +               }
 144 +               num++;
 145 +       }
 146 +       /* lock not found */
 147 +       if (nhl) {
 148 +               /* we already have allocated lock. use it */
 149 +               hl = nhl;
 150 +               nhl = NULL;
 151 +               list_add(&hl->dl_list, &dl->dl_list);
 152 +               goto found;
 153 +       }
 154 +       spin_unlock(&dl->dl_list_lock);
 155 +
 156 +       /* lock not found and we haven't allocated lock yet. allocate it */
 157 +       nhl = kmalloc(sizeof(struct dynlock_member), gfp);
 158 +       if (nhl == NULL)
 159 +               return NULL;
 160 +       nhl->dl_refcount = 1;
 161 +       nhl->dl_value = value;
 162 +       nhl->dl_readers = 0;
 163 +       nhl->dl_writers = 0;
 164 +       nhl->dl_magic = DYNLOCK_MAGIC;
 165 +       nhl->dl_head = dl;
 166 +       init_waitqueue_head(&nhl->dl_wait);
 167 +
 168 +       /* while lock is being allocated, someone else may allocate it
 169 +        * and put onto to list. check this situation
 170 +        */
 171 +       goto repeat;
 172 +
 173 +found:
 174 +       if (rw) {
 175 +               /* exclusive lock: user don't want to share lock at all
 176 +                * NOTE: one process may take the same lock several times
 177 +                * this functionaly is useful for rename operations */
 178 +               while ((hl->dl_writers && hl->dl_pid != current->pid) ||
 179 +                               hl->dl_readers) {
 180 +                       spin_unlock(&dl->dl_list_lock);
 181 +                       wait_event(hl->dl_wait,
 182 +                               hl->dl_writers == 0 && hl->dl_readers == 0);
 183 +                       spin_lock(&dl->dl_list_lock);
 184 +               }
 185 +               hl->dl_writers++;
 186 +       } else {
 187 +               /* shared lock: user do not want to share lock with writer */
 188 +               while (hl->dl_writers) {
 189 +                       spin_unlock(&dl->dl_list_lock);
 190 +                       wait_event(hl->dl_wait, hl->dl_writers == 0);
 191 +                       spin_lock(&dl->dl_list_lock);
 192 +               }
 193 +               hl->dl_readers++;
 194 +       }
 195 +       hl->dl_pid = current->pid;
 196 +       spin_unlock(&dl->dl_list_lock);
 197 +
 198 +       BUG_ON(hl->dl_magic != DYNLOCK_MAGIC);
 199 +       return hl;
 200 +}
 201 +
 202 +
 203 +/*
 204 + * dynlock_unlock
 205 + *
 206 + * user have to specify lockspace (dl) and pointer to lock structure
 207 + * returned by dynlock_lock()
 208 + *
 209 + */
 210 +void dynlock_unlock(struct dynlock *dl, void *lock)
 211 +{
 212 +       struct dynlock_member *hl = lock;
 213 +       int wakeup = 0;
 214 +
 215 +       BUG_ON(dl == NULL);
 216 +       BUG_ON(hl == NULL);
 217 +       BUG_ON(dl->dl_magic != DYNLOCK_LIST_MAGIC);
 218 +       BUG_ON(dl->dl_back != dl);
 219 +       if (hl->dl_magic != DYNLOCK_MAGIC || hl->dl_head != dl) {
 220 +               printk("corrupted lock 0x%p: magic 0x%x (!=0x%x)\n",
 221 +                               hl, hl->dl_magic, DYNLOCK_MAGIC);
 222 +               printk("  value 0x%lx, %d readers, %d writers, pid %d, %d refs\n",
 223 +                               hl->dl_value, hl->dl_readers, hl->dl_writers,
 224 +                               hl->dl_pid, hl->dl_refcount);
 225 +               printk("   head 0x%p\n", hl->dl_head);
 226 +               BUG();
 227 +       }
 228 +       BUG_ON(current->pid != hl->dl_pid);
 229 +
 230 +       spin_lock(&dl->dl_list_lock);
 231 +       if (hl->dl_writers) {
 232 +               BUG_ON(hl->dl_readers > 0 || hl->dl_readers < 0);
 233 +               hl->dl_writers--;
 234 +               if (hl->dl_writers == 0)
 235 +                       wakeup = 1;
 236 +       } else if (hl->dl_readers) {
 237 +               hl->dl_readers--;
 238 +               if (hl->dl_readers == 0)
 239 +                       wakeup = 1;
 240 +       } else {
 241 +               BUG_ON(1);
 242 +       }
 243 +       if (wakeup) {
 244 +               hl->dl_pid = 0;
 245 +               wake_up(&hl->dl_wait);
 246 +       }
 247 +       if (--(hl->dl_refcount) == 0) {
 248 +               hl->dl_magic = DYNLOCK_MAGIC2;
 249 +               list_del(&hl->dl_list);
 250 +       }
 251 +       spin_unlock(&dl->dl_list_lock);
 252 +       if (hl->dl_refcount == 0)
 253 +               kfree(hl);
 254 +}
 255 +
 256 +EXPORT_SYMBOL(dynlock_init);
 257 +EXPORT_SYMBOL(dynlock_lock);
 258 +EXPORT_SYMBOL(dynlock_unlock);
 259 +
 260 Index: linux-2.4.24/lib/Makefile
 261 ===================================================================
 262 --- linux-2.4.24.orig/lib/Makefile      2004-06-24 09:06:32.000000000 +0400
 263 +++ linux-2.4.24/lib/Makefile   2004-07-14 18:14:28.000000000 +0400
 264 @@ -9,10 +9,10 @@
 265  L_TARGET := lib.a
 266
 267  export-objs := cmdline.o dec_and_lock.o rwsem-spinlock.o rwsem.o \
 268 -              rbtree.o crc32.o firmware_class.o
 269 +              rbtree.o crc32.o firmware_class.o dynlocks.o
 270
 271  obj-y := errno.o ctype.o string.o vsprintf.o brlock.o cmdline.o \
 272 -        bust_spinlocks.o rbtree.o dump_stack.o
 273 +        bust_spinlocks.o rbtree.o dump_stack.o dynlocks.o
 274
 275  obj-$(CONFIG_FW_LOADER) += firmware_class.o
 276  obj-$(CONFIG_RWSEM_GENERIC_SPINLOCK) += rwsem-spinlock.o