src/rx/LINUX/rx_kmutex.c

   1 /*
   2  * Copyright 2000, International Business Machines Corporation and others.
   3  * All Rights Reserved.
   4  *
   5  * This software has been released under the terms of the IBM Public
   6  * License.  For details, see the LICENSE file in the top-level source
   7  * directory or online at http://www.openafs.org/dl/license10.html
   8  */
   9
  10 /*
  11  * rx_kmutex.c - mutex and condition variable macros for kernel environment.
  12  *
  13  * Linux implementation.
  14  */
  15
  16 #include <afsconfig.h>
  17 #include "afs/param.h"
  18
  19
  20 #include "rx/rx_kcommon.h"
  21 #include "rx_kmutex.h"
  22 #include "rx/rx_kernel.h"
  23
  24 #include "osi_compat.h"
  25
  26 void
  27 afs_mutex_init(afs_kmutex_t * l)
  28 {
  29 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16)
  30     mutex_init(&l->mutex);
  31 #elif LINUX_VERSION_CODE >= KERNEL_VERSION(2,4,0)
  32     init_MUTEX(&l->sem);
  33 #else
  34     l->sem = MUTEX;
  35 #endif
  36     l->owner = 0;
  37 }
  38
  39 void
  40 afs_mutex_enter(afs_kmutex_t * l)
  41 {
  42 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16)
  43     mutex_lock(&l->mutex);
  44 #else
  45     down(&l->sem);
  46 #endif
  47     if (l->owner)
  48         osi_Panic("mutex_enter: 0x%lx held by %d", (unsigned long)l, l->owner);
  49     l->owner = current->pid;
  50 }
  51
  52 int
  53 afs_mutex_tryenter(afs_kmutex_t * l)
  54 {
  55 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16)
  56     if (mutex_trylock(&l->mutex) == 0)
  57 #else
  58     if (down_trylock(&l->sem))
  59 #endif
  60         return 0;
  61     l->owner = current->pid;
  62     return 1;
  63 }
  64
  65 void
  66 afs_mutex_exit(afs_kmutex_t * l)
  67 {
  68     if (l->owner != current->pid)
  69         osi_Panic("mutex_exit: 0x%lx held by %d", (unsigned long)l, l->owner);
  70     l->owner = 0;
  71 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16)
  72     mutex_unlock(&l->mutex);
  73 #else
  74     up(&l->sem);
  75 #endif
  76 }
  77
  78 /* CV_WAIT and CV_TIMEDWAIT sleep until the specified event occurs, or, in the
  79  * case of CV_TIMEDWAIT, until the specified timeout occurs.
  80  * - NOTE: that on Linux, there are circumstances in which TASK_INTERRUPTIBLE
  81  *   can wake up, even if all signals are blocked
  82  * - TODO: handle signals correctly by passing an indication back to the
  83  *   caller that the wait has been interrupted and the stack should be cleaned
  84  *   up preparatory to signal delivery
  85  */
  86 int
  87 afs_cv_wait(afs_kcondvar_t * cv, afs_kmutex_t * l, int sigok)
  88 {
  89     int seq, isAFSGlocked = ISAFS_GLOCK();
  90     sigset_t saved_set;
  91 #ifdef DECLARE_WAITQUEUE
  92     DECLARE_WAITQUEUE(wait, current);
  93 #else
  94     struct wait_queue wait = { current, NULL };
  95 #endif
  96     sigemptyset(&saved_set);
  97     seq = cv->seq;
  98
  99     set_current_state(TASK_INTERRUPTIBLE);
 100     add_wait_queue(&cv->waitq, &wait);
 101
 102     if (isAFSGlocked)
 103         AFS_GUNLOCK();
 104     MUTEX_EXIT(l);
 105
 106     if (!sigok) {
 107         SIG_LOCK(current);
 108         saved_set = current->blocked;
 109         sigfillset(&current->blocked);
 110         RECALC_SIGPENDING(current);
 111         SIG_UNLOCK(current);
 112     }
 113
 114     while(seq == cv->seq) {
 115         schedule();
 116         afs_try_to_freeze();
 117         set_current_state(TASK_INTERRUPTIBLE);
 118     }
 119
 120     remove_wait_queue(&cv->waitq, &wait);
 121     set_current_state(TASK_RUNNING);
 122
 123     if (!sigok) {
 124         SIG_LOCK(current);
 125         current->blocked = saved_set;
 126         RECALC_SIGPENDING(current);
 127         SIG_UNLOCK(current);
 128     }
 129
 130     if (isAFSGlocked)
 131         AFS_GLOCK();
 132     MUTEX_ENTER(l);
 133
 134     return (sigok && signal_pending(current)) ? EINTR : 0;
 135 }
 136
 137 void
 138 afs_cv_timedwait(afs_kcondvar_t * cv, afs_kmutex_t * l, int waittime)
 139 {
 140     int seq, isAFSGlocked = ISAFS_GLOCK();
 141     long t = waittime * HZ / 1000;
 142 #ifdef DECLARE_WAITQUEUE
 143     DECLARE_WAITQUEUE(wait, current);
 144 #else
 145     struct wait_queue wait = { current, NULL };
 146 #endif
 147     seq = cv->seq;
 148
 149     set_current_state(TASK_INTERRUPTIBLE);
 150     add_wait_queue(&cv->waitq, &wait);
 151
 152     if (isAFSGlocked)
 153         AFS_GUNLOCK();
 154     MUTEX_EXIT(l);
 155
 156     while(seq == cv->seq) {
 157         t = schedule_timeout(t);
 158         if (!t)         /* timeout */
 159             break;
 160     }
 161
 162     remove_wait_queue(&cv->waitq, &wait);
 163     set_current_state(TASK_RUNNING);
 164
 165     if (isAFSGlocked)
 166         AFS_GLOCK();
 167     MUTEX_ENTER(l);
 168 }