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       2004-07-18 11:09:33.000000000 +0400
  10 @@ -0,0 +1,43 @@
  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 +};
  32 +
  33 +/*
  34 + * lock's namespace:
  35 + *   - list of locks
  36 + *   - lock to protect this list
  37 + */
  38 +
  39 +#define DYNLOCK_LIST_MAGIC     0x11ee91e6
  40 +
  41 +struct dynlock {
  42 +       unsigned dl_magic;
  43 +       struct list_head dl_list;
  44 +       spinlock_t dl_list_lock;
  45 +};
  46 +
  47 +void dynlock_init(struct dynlock *dl);
  48 +void *dynlock_lock(struct dynlock *dl, unsigned long value, int rw, int gfp);
  49 +void dynlock_unlock(struct dynlock *dl, void *lock);
  50 +
  51 +
  52 +#endif
  53 +
  54 Index: linux-2.4.24/lib/dynlocks.c
  55 ===================================================================
  56 --- linux-2.4.24.orig/lib/dynlocks.c    2003-01-30 13:24:37.000000000 +0300
  57 +++ linux-2.4.24/lib/dynlocks.c 2004-07-18 11:23:01.000000000 +0400
  58 @@ -0,0 +1,188 @@
  59 +/*
  60 + * Dynamic Locks
  61 + *
  62 + * struct dynlock is lockspace
  63 + * one may request lock (exclusive or shared) for some value
  64 + * in that lockspace
  65 + *
  66 + */
  67 +
  68 +#include <linux/dynlocks.h>
  69 +#include <linux/module.h>
  70 +#include <linux/slab.h>
  71 +#include <linux/sched.h>
  72 +#include <linux/init.h>
  73 +
  74 +static kmem_cache_t * dynlock_cachep = NULL;
  75 +
  76 +void __init dynlock_cache_init(void)
  77 +{
  78 +       printk(KERN_INFO "init dynlocks cache\n");
  79 +       dynlock_cachep = kmem_cache_create("dynlock_cache",
  80 +                                        sizeof(struct dynlock_member),
  81 +                                        0,
  82 +                                        SLAB_HWCACHE_ALIGN,
  83 +                                        NULL, NULL);
  84 +       if (dynlock_cachep == NULL)
  85 +               panic("Can't create dynlock cache");
  86 +}
  87 +
  88 +/*
  89 + * dynlock_init
  90 + *
  91 + * initialize lockspace
  92 + *
  93 + */
  94 +void dynlock_init(struct dynlock *dl)
  95 +{
  96 +       spin_lock_init(&dl->dl_list_lock);
  97 +       INIT_LIST_HEAD(&dl->dl_list);
  98 +       dl->dl_magic = DYNLOCK_LIST_MAGIC;
  99 +}
 100 +
 101 +/*
 102 + * dynlock_lock
 103 + *
 104 + * acquires lock (exclusive or shared) in specified lockspace
 105 + * each lock in lockspace is allocated separately, so user have
 106 + * to specify GFP flags.
 107 + * routine returns pointer to lock. this pointer is intended to
 108 + * be passed to dynlock_unlock
 109 + *
 110 + */
 111 +void *dynlock_lock(struct dynlock *dl, unsigned long value, int rw, int gfp)
 112 +{
 113 +       struct dynlock_member *nhl = NULL;
 114 +       struct dynlock_member *hl;
 115 +       struct list_head *cur;
 116 +       int num = 0;
 117 +
 118 +       BUG_ON(dl == NULL);
 119 +       BUG_ON(dl->dl_magic != DYNLOCK_LIST_MAGIC);
 120 +repeat:
 121 +       /* find requested lock in lockspace */
 122 +       spin_lock(&dl->dl_list_lock);
 123 +       BUG_ON(dl->dl_list.next == NULL);
 124 +       BUG_ON(dl->dl_list.prev == NULL);
 125 +       list_for_each(cur, &dl->dl_list) {
 126 +               BUG_ON(cur->next == NULL);
 127 +               BUG_ON(cur->prev == NULL);
 128 +               hl = list_entry(cur, struct dynlock_member, dl_list);
 129 +               BUG_ON(hl->dl_magic != DYNLOCK_MAGIC);
 130 +               if (hl->dl_value == value) {
 131 +                       /* lock is found */
 132 +                       if (nhl) {
 133 +                               /* someone else just allocated
 134 +                                * lock we didn't find and just created
 135 +                                * so, we drop our lock
 136 +                                */
 137 +                               kmem_cache_free(dynlock_cachep, nhl);
 138 +                               nhl = NULL;
 139 +                       }
 140 +                       hl->dl_refcount++;
 141 +                       goto found;
 142 +               }
 143 +               num++;
 144 +       }
 145 +       /* lock not found */
 146 +       if (nhl) {
 147 +               /* we already have allocated lock. use it */
 148 +               hl = nhl;
 149 +               nhl = NULL;
 150 +               list_add(&hl->dl_list, &dl->dl_list);
 151 +               goto found;
 152 +       }
 153 +       spin_unlock(&dl->dl_list_lock);
 154 +
 155 +       /* lock not found and we haven't allocated lock yet. allocate it */
 156 +       nhl = kmem_cache_alloc(dynlock_cachep, gfp);
 157 +       if (nhl == NULL)
 158 +               return NULL;
 159 +       nhl->dl_refcount = 1;
 160 +       nhl->dl_value = value;
 161 +       nhl->dl_readers = 0;
 162 +       nhl->dl_writers = 0;
 163 +       nhl->dl_magic = DYNLOCK_MAGIC;
 164 +       init_waitqueue_head(&nhl->dl_wait);
 165 +
 166 +       /* while lock is being allocated, someone else may allocate it
 167 +        * and put onto to list. check this situation
 168 +        */
 169 +       goto repeat;
 170 +
 171 +found:
 172 +       if (rw) {
 173 +               /* exclusive lock: user don't want to share lock at all
 174 +                * NOTE: one process may take the same lock several times
 175 +                * this functionaly is useful for rename operations */
 176 +               while ((hl->dl_writers && hl->dl_pid != current->pid) ||
 177 +                               hl->dl_readers) {
 178 +                       spin_unlock(&dl->dl_list_lock);
 179 +                       wait_event(hl->dl_wait,
 180 +                               hl->dl_writers == 0 && hl->dl_readers == 0);
 181 +                       spin_lock(&dl->dl_list_lock);
 182 +               }
 183 +               hl->dl_writers++;
 184 +       } else {
 185 +               /* shared lock: user do not want to share lock with writer */
 186 +               while (hl->dl_writers) {
 187 +                       spin_unlock(&dl->dl_list_lock);
 188 +                       wait_event(hl->dl_wait, hl->dl_writers == 0);
 189 +                       spin_lock(&dl->dl_list_lock);
 190 +               }
 191 +               hl->dl_readers++;
 192 +       }
 193 +       hl->dl_pid = current->pid;
 194 +       spin_unlock(&dl->dl_list_lock);
 195 +
 196 +       return hl;
 197 +}
 198 +
 199 +
 200 +/*
 201 + * dynlock_unlock
 202 + *
 203 + * user have to specify lockspace (dl) and pointer to lock structure
 204 + * returned by dynlock_lock()
 205 + *
 206 + */
 207 +void dynlock_unlock(struct dynlock *dl, void *lock)
 208 +{
 209 +       struct dynlock_member *hl = lock;
 210 +       int wakeup = 0;
 211 +
 212 +       BUG_ON(dl == NULL);
 213 +       BUG_ON(hl == NULL);
 214 +       BUG_ON(dl->dl_magic != DYNLOCK_LIST_MAGIC);
 215 +       BUG_ON(hl->dl_magic != DYNLOCK_MAGIC);
 216 +       BUG_ON(current->pid != hl->dl_pid);
 217 +
 218 +       spin_lock(&dl->dl_list_lock);
 219 +       if (hl->dl_writers) {
 220 +               BUG_ON(hl->dl_readers > 0 || hl->dl_readers < 0);
 221 +               hl->dl_writers--;
 222 +               if (hl->dl_writers == 0)
 223 +                       wakeup = 1;
 224 +       } else if (hl->dl_readers) {
 225 +               hl->dl_readers--;
 226 +               if (hl->dl_readers == 0)
 227 +                       wakeup = 1;
 228 +       } else {
 229 +               BUG_ON(1);
 230 +       }
 231 +       if (wakeup) {
 232 +               hl->dl_pid = 0;
 233 +               wake_up(&hl->dl_wait);
 234 +       }
 235 +       if (--(hl->dl_refcount) == 0) {
 236 +               hl->dl_magic = DYNLOCK_MAGIC2;
 237 +               list_del(&hl->dl_list);
 238 +               kmem_cache_free(dynlock_cachep, hl);
 239 +       }
 240 +       spin_unlock(&dl->dl_list_lock);
 241 +}
 242 +
 243 +EXPORT_SYMBOL(dynlock_init);
 244 +EXPORT_SYMBOL(dynlock_lock);
 245 +EXPORT_SYMBOL(dynlock_unlock);
 246 +
 247 Index: linux-2.4.24/lib/Makefile
 248 ===================================================================
 249 --- linux-2.4.24.orig/lib/Makefile      2004-06-24 09:06:32.000000000 +0400
 250 +++ linux-2.4.24/lib/Makefile   2004-07-16 15:54:06.000000000 +0400
 251 @@ -9,10 +9,10 @@
 252  L_TARGET := lib.a
 253
 254  export-objs := cmdline.o dec_and_lock.o rwsem-spinlock.o rwsem.o \
 255 -              rbtree.o crc32.o firmware_class.o
 256 +              rbtree.o crc32.o firmware_class.o dynlocks.o
 257
 258  obj-y := errno.o ctype.o string.o vsprintf.o brlock.o cmdline.o \
 259 -        bust_spinlocks.o rbtree.o dump_stack.o
 260 +        bust_spinlocks.o rbtree.o dump_stack.o dynlocks.o
 261
 262  obj-$(CONFIG_FW_LOADER) += firmware_class.o
 263  obj-$(CONFIG_RWSEM_GENERIC_SPINLOCK) += rwsem-spinlock.o
 264 Index: linux-2.4.24/fs/dcache.c
 265 ===================================================================
 266 --- linux-2.4.24.orig/fs/dcache.c       2004-07-16 12:35:54.000000000 +0400
 267 +++ linux-2.4.24/fs/dcache.c    2004-07-16 15:54:06.000000000 +0400
 268 @@ -1274,6 +1274,7 @@
 269  extern void bdev_cache_init(void);
 270  extern void cdev_cache_init(void);
 271  extern void iobuf_cache_init(void);
 272 +extern void dynlock_cache_init(void);
 273
 274  void __init vfs_caches_init(unsigned long mempages)
 275  {
 276 @@ -1310,4 +1311,5 @@
 277         bdev_cache_init();
 278         cdev_cache_init();
 279         iobuf_cache_init();
 280 +       dynlock_cache_init();
 281  }