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       2004-07-06 19:14:17.000000000 +0400
  10 @@ -0,0 +1,41 @@
  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_member {
  21 +       unsigned                dl_magic;
  22 +       struct list_head        dl_list;
  23 +       unsigned long           dl_value;       /* lock value */
  24 +       int                     dl_refcount;    /* number of users */
  25 +       int                     dl_readers;
  26 +       int                     dl_writers;
  27 +       int                     dl_pid;         /* holder of the lock */
  28 +       wait_queue_head_t       dl_wait;
  29 +};
  30 +
  31 +/*
  32 + * lock's namespace:
  33 + *   - list of locks
  34 + *   - lock to protect this list
  35 + */
  36 +
  37 +#define DYNLOCK_LIST_MAGIC     0x11ee91e6
  38 +
  39 +struct dynlock {
  40 +       unsigned dl_magic;
  41 +       struct list_head dl_list;
  42 +       spinlock_t dl_list_lock;
  43 +};
  44 +
  45 +void dynlock_init(struct dynlock *dl);
  46 +void *dynlock_lock(struct dynlock *dl, unsigned long value, int rw, int gfp);
  47 +void dynlock_unlock(struct dynlock *dl, void *lock);
  48 +
  49 +
  50 +#endif
  51 +
  52 Index: linux-2.4.24/lib/dynlocks.c
  53 ===================================================================
  54 --- linux-2.4.24.orig/lib/dynlocks.c    2003-01-30 13:24:37.000000000 +0300
  55 +++ linux-2.4.24/lib/dynlocks.c 2004-07-06 19:14:40.000000000 +0400
  56 @@ -0,0 +1,173 @@
  57 +/*
  58 + * Dynamic Locks
  59 + *
  60 + * struct dynlock is lockspace
  61 + * one may request lock (exclusive or shared) for some value
  62 + * in that lockspace
  63 + *
  64 + */
  65 +
  66 +#include <linux/dynlocks.h>
  67 +#include <linux/module.h>
  68 +#include <linux/slab.h>
  69 +#include <linux/sched.h>
  70 +
  71 +/*
  72 + * dynlock_init
  73 + *
  74 + * initialize lockspace
  75 + *
  76 + */
  77 +void dynlock_init(struct dynlock *dl)
  78 +{
  79 +       spin_lock_init(&dl->dl_list_lock);
  80 +       INIT_LIST_HEAD(&dl->dl_list);
  81 +       dl->dl_magic = DYNLOCK_LIST_MAGIC;
  82 +}
  83 +
  84 +/*
  85 + * dynlock_lock
  86 + *
  87 + * acquires lock (exclusive or shared) in specified lockspace
  88 + * each lock in lockspace is allocated separately, so user have
  89 + * to specify GFP flags.
  90 + * routine returns pointer to lock. this pointer is intended to
  91 + * be passed to dynlock_unlock
  92 + *
  93 + */
  94 +void *dynlock_lock(struct dynlock *dl, unsigned long value, int rw, int gfp)
  95 +{
  96 +       struct dynlock_member *nhl = NULL;
  97 +       struct dynlock_member *hl;
  98 +       struct list_head *cur;
  99 +
 100 +       BUG_ON(dl == NULL);
 101 +       BUG_ON(dl->dl_magic != DYNLOCK_LIST_MAGIC);
 102 +repeat:
 103 +       /* find requested lock in lockspace */
 104 +       spin_lock(&dl->dl_list_lock);
 105 +       BUG_ON(dl->dl_list.next == NULL);
 106 +       BUG_ON(dl->dl_list.prev == NULL);
 107 +       list_for_each(cur, &dl->dl_list) {
 108 +               BUG_ON(cur->next == NULL);
 109 +               BUG_ON(cur->prev == NULL);
 110 +               hl = list_entry(cur, struct dynlock_member, dl_list);
 111 +               BUG_ON(hl->dl_magic != DYNLOCK_MAGIC);
 112 +               if (hl->dl_value == value) {
 113 +                       /* lock is found */
 114 +                       if (nhl) {
 115 +                               /* someone else just allocated
 116 +                                * lock we didn't find and just created
 117 +                                * so, we drop our lock
 118 +                                */
 119 +                               kfree(nhl);
 120 +                               nhl = NULL;
 121 +                       }
 122 +                       hl->dl_refcount++;
 123 +                       goto found;
 124 +               }
 125 +       }
 126 +       /* lock not found */
 127 +       if (nhl) {
 128 +               /* we already have allocated lock. use it */
 129 +               hl = nhl;
 130 +               nhl = NULL;
 131 +               list_add(&hl->dl_list, &dl->dl_list);
 132 +               goto found;
 133 +       }
 134 +       spin_unlock(&dl->dl_list_lock);
 135 +
 136 +       /* lock not found and we haven't allocated lock yet. allocate it */
 137 +       nhl = kmalloc(sizeof(struct dynlock_member), gfp);
 138 +       if (nhl == NULL)
 139 +               return NULL;
 140 +       nhl->dl_refcount = 1;
 141 +       nhl->dl_value = value;
 142 +       nhl->dl_readers = 0;
 143 +       nhl->dl_writers = 0;
 144 +       nhl->dl_magic = DYNLOCK_MAGIC;
 145 +       init_waitqueue_head(&nhl->dl_wait);
 146 +
 147 +       /* while lock is being allocated, someone else may allocate it
 148 +        * and put onto to list. check this situation
 149 +        */
 150 +       goto repeat;
 151 +
 152 +found:
 153 +       if (rw) {
 154 +               /* exclusive lock: user don't want to share lock at all
 155 +                * NOTE: one process may take the same lock several times
 156 +                * this functionaly is useful for rename operations */
 157 +               while ((hl->dl_writers && hl->dl_pid != current->pid) ||
 158 +                               hl->dl_readers) {
 159 +                       spin_unlock(&dl->dl_list_lock);
 160 +                       wait_event(hl->dl_wait,
 161 +                               hl->dl_writers == 0 && hl->dl_readers == 0);
 162 +                       spin_lock(&dl->dl_list_lock);
 163 +               }
 164 +               hl->dl_writers++;
 165 +       } else {
 166 +               /* shared lock: user do not want to share lock with writer */
 167 +               while (hl->dl_writers) {
 168 +                       spin_unlock(&dl->dl_list_lock);
 169 +                       wait_event(hl->dl_wait, hl->dl_writers == 0);
 170 +                       spin_lock(&dl->dl_list_lock);
 171 +               }
 172 +               hl->dl_readers++;
 173 +       }
 174 +       hl->dl_pid = current->pid;
 175 +       spin_unlock(&dl->dl_list_lock);
 176 +
 177 +       BUG_ON(hl->dl_magic != DYNLOCK_MAGIC);
 178 +       return hl;
 179 +}
 180 +
 181 +
 182 +/*
 183 + * dynlock_unlock
 184 + *
 185 + * user have to specify lockspace (dl) and pointer to lock structure
 186 + * returned by dynlock_lock()
 187 + *
 188 + */
 189 +void dynlock_unlock(struct dynlock *dl, void *lock)
 190 +{
 191 +       struct dynlock_member *hl = lock;
 192 +       int wakeup = 0;
 193 +
 194 +       BUG_ON(dl == NULL);
 195 +       BUG_ON(hl == NULL);
 196 +       BUG_ON(dl->dl_magic != DYNLOCK_LIST_MAGIC);
 197 +       BUG_ON(hl->dl_magic != DYNLOCK_MAGIC);
 198 +       BUG_ON(current->pid != hl->dl_pid);
 199 +
 200 +       spin_lock(&dl->dl_list_lock);
 201 +       if (hl->dl_writers) {
 202 +               BUG_ON(hl->dl_readers > 0 || hl->dl_readers < 0);
 203 +               hl->dl_writers--;
 204 +               if (hl->dl_writers == 0)
 205 +                       wakeup = 1;
 206 +       } else if (hl->dl_readers) {
 207 +               hl->dl_readers--;
 208 +               if (hl->dl_readers == 0)
 209 +                       wakeup = 1;
 210 +       } else {
 211 +               BUG_ON(1);
 212 +       }
 213 +       if (wakeup) {
 214 +               hl->dl_pid = 0;
 215 +               wake_up(&hl->dl_wait);
 216 +       }
 217 +       if (--(hl->dl_refcount) == 0) {
 218 +               hl->dl_magic = DYNLOCK_MAGIC2;
 219 +               list_del(&hl->dl_list);
 220 +       }
 221 +       spin_unlock(&dl->dl_list_lock);
 222 +       if (hl->dl_refcount == 0)
 223 +               kfree(hl);
 224 +}
 225 +
 226 +EXPORT_SYMBOL(dynlock_init);
 227 +EXPORT_SYMBOL(dynlock_lock);
 228 +EXPORT_SYMBOL(dynlock_unlock);
 229 +
 230 Index: linux-2.4.24/lib/Makefile
 231 ===================================================================
 232 --- linux-2.4.24.orig/lib/Makefile      2004-06-24 09:06:32.000000000 +0400
 233 +++ linux-2.4.24/lib/Makefile   2004-07-06 19:14:17.000000000 +0400
 234 @@ -9,10 +9,10 @@
 235  L_TARGET := lib.a
 236
 237  export-objs := cmdline.o dec_and_lock.o rwsem-spinlock.o rwsem.o \
 238 -              rbtree.o crc32.o firmware_class.o
 239 +              rbtree.o crc32.o firmware_class.o dynlocks.o
 240
 241  obj-y := errno.o ctype.o string.o vsprintf.o brlock.o cmdline.o \
 242 -        bust_spinlocks.o rbtree.o dump_stack.o
 243 +        bust_spinlocks.o rbtree.o dump_stack.o dynlocks.o
 244
 245  obj-$(CONFIG_FW_LOADER) += firmware_class.o
 246  obj-$(CONFIG_RWSEM_GENERIC_SPINLOCK) += rwsem-spinlock.o