Use per-subdevice spin-lock instead of big_comedi_lock. Renamed existing

subdevice 'runflags_lock' to 'spin_lock' for more general use.  (Could have
used a separate spin-lock for locking/unlocking subdevices, but there
shouldn't be much contention for the existing spin-lock used for setting/
getting runflags.)

diff --git a/comedi/comedi_fops.c b/comedi/comedi_fops.c
index 2513b014e528902e7ba917df713a088076d2c9a9..e686a1786dea48f2649d10811b2e4b4ac635989a 100644 (file)
--- a/comedi/comedi_fops.c
+++ b/comedi/comedi_fops.c
@@ -60,7 +60,6 @@ module_param(comedi_debug, int, 0644);
 #endif
 
 comedi_device *comedi_devices;
-spinlock_t big_comedi_lock;    /* Dynamic initialization */
 
 static int do_devconfig_ioctl(comedi_device * dev, comedi_devconfig * arg);
 static int do_bufconfig_ioctl(comedi_device * dev, void *arg);
@@ -1159,17 +1158,13 @@ static int do_lock_ioctl(comedi_device * dev, unsigned int arg, void *file)
                return -EINVAL;
        s = dev->subdevices + arg;
 
-       comedi_spin_lock_irqsave(&big_comedi_lock, flags);
-       if (s->busy) {
-               comedi_spin_unlock_irqrestore(&big_comedi_lock, flags);
-               return -EBUSY;
-       }
-       if (s->lock) {
+       comedi_spin_lock_irqsave(&s->spin_lock, flags);
+       if (s->busy || s->lock) {
                ret = -EBUSY;
        } else {
                s->lock = file;
        }
-       comedi_spin_unlock_irqrestore(&big_comedi_lock, flags);
+       comedi_spin_unlock_irqrestore(&s->spin_lock, flags);
 
        if (ret < 0)
                return ret;
@@ -1753,7 +1748,6 @@ static int __init comedi_init(void)
 
        printk("comedi: version " COMEDI_RELEASE
                " - David Schleef <ds@schleef.org>\n");
-       spin_lock_init(&big_comedi_lock);
        retval = register_chrdev_region(MKDEV(COMEDI_MAJOR, 0),
                COMEDI_NUM_MINORS, "comedi");
        if (retval)
@@ -1912,10 +1906,10 @@ void comedi_set_subdevice_runflags(comedi_subdevice * s, unsigned mask,
 {
        unsigned long flags;
 
-       comedi_spin_lock_irqsave(&s->runflags_lock, flags);
+       comedi_spin_lock_irqsave(&s->spin_lock, flags);
        s->runflags &= ~mask;
        s->runflags |= (bits & mask);
-       comedi_spin_unlock_irqrestore(&s->runflags_lock, flags);
+       comedi_spin_unlock_irqrestore(&s->spin_lock, flags);
 }
 
 unsigned comedi_get_subdevice_runflags(comedi_subdevice * s)
@@ -1923,8 +1917,8 @@ unsigned comedi_get_subdevice_runflags(comedi_subdevice * s)
        unsigned long flags;
        unsigned runflags;
 
-       comedi_spin_lock_irqsave(&s->runflags_lock, flags);
+       comedi_spin_lock_irqsave(&s->spin_lock, flags);
        runflags = s->runflags;
-       comedi_spin_unlock_irqrestore(&s->runflags_lock, flags);
+       comedi_spin_unlock_irqrestore(&s->spin_lock, flags);
        return runflags;
 }

diff --git a/comedi/comedi_ksyms.c b/comedi/comedi_ksyms.c
index bfdafed38cd5381ebe7030e435a90984a5847dc1..1189a896de329c3652d776651c3df2bce740669d 100644 (file)
--- a/comedi/comedi_ksyms.c
+++ b/comedi/comedi_ksyms.c
@@ -61,7 +61,6 @@ EXPORT_SYMBOL(comedi_debug);
 
 /* for kcomedilib */
 EXPORT_SYMBOL(comedi_devices);
-EXPORT_SYMBOL(big_comedi_lock);
 EXPORT_SYMBOL(check_chanlist);
 
 EXPORT_SYMBOL(comedi_buf_put);

diff --git a/comedi/kcomedilib/kcomedilib_main.c b/comedi/kcomedilib/kcomedilib_main.c
index fecfecb716fe13a93d82ecdc3eaf22c0d400ec38..c68e64cf50cd72a2ce9f4fe4731c9cdd20ad506a 100644 (file)
--- a/comedi/kcomedilib/kcomedilib_main.c
+++ b/comedi/kcomedilib/kcomedilib_main.c
@@ -312,7 +312,7 @@ int comedi_lock(comedi_t * d, unsigned int subdevice)
        unsigned long flags;
        int ret = 0;
 
-       comedi_spin_lock_irqsave(&big_comedi_lock, flags);
+       comedi_spin_lock_irqsave(&s->spin_lock, flags);
 
        if (s->busy) {
                ret = -EBUSY;
@@ -324,7 +324,7 @@ int comedi_lock(comedi_t * d, unsigned int subdevice)
                }
        }
 
-       comedi_spin_unlock_irqrestore(&big_comedi_lock, flags);
+       comedi_spin_unlock_irqrestore(&s->spin_lock, flags);
 
        return ret;
 }
@@ -349,32 +349,31 @@ int comedi_unlock(comedi_t * d, unsigned int subdevice)
        comedi_subdevice *s = dev->subdevices + subdevice;
        unsigned long flags;
        comedi_async *async;
+       int ret;
 
        async = s->async;
 
-       comedi_spin_lock_irqsave(&big_comedi_lock, flags);
+       comedi_spin_lock_irqsave(&s->spin_lock, flags);
 
        if (s->busy) {
-               comedi_spin_unlock_irqrestore(&big_comedi_lock, flags);
-               return -EBUSY;
-       }
-
-       if (s->lock && s->lock != (void *)d) {
-               comedi_spin_unlock_irqrestore(&big_comedi_lock, flags);
-               return -EACCES;
-       }
+               ret = -EBUSY;
+       } else if (s->lock && s->lock != (void *)d) {
+               ret = -EACCES;
+       } else {
+               s->lock = NULL;
 
-       s->lock = NULL;
+               if (async) {
+                       async->cb_mask = 0;
+                       async->cb_func = NULL;
+                       async->cb_arg = NULL;
+               }
 
-       if (async) {
-               async->cb_mask = 0;
-               async->cb_func = NULL;
-               async->cb_arg = NULL;
+               ret = 0;
        }
 
-       comedi_spin_unlock_irqrestore(&big_comedi_lock, flags);
+       comedi_spin_unlock_irqrestore(&s->spin_lock, flags);
 
-       return 0;
+       return ret;
 }
 
 /*

diff --git a/include/linux/comedidev.h b/include/linux/comedidev.h
index 500d11d3ad6fe76796a8bb6014d3821f87735dc0..86bb00724d2e931212f15a512182ff43aa00886f 100644 (file)
--- a/include/linux/comedidev.h
+++ b/include/linux/comedidev.h
@@ -106,7 +106,7 @@ struct comedi_subdevice_struct {
        void *lock;
        void *busy;
        unsigned runflags;
-       spinlock_t runflags_lock;
+       spinlock_t spin_lock;
 
        int io_bits;
 
@@ -256,7 +256,6 @@ struct comedi_inode_private {
 };
 
 extern comedi_device *comedi_devices;
-extern spinlock_t big_comedi_lock;
 
 #ifdef CONFIG_COMEDI_DEBUG
 extern int comedi_debug;
@@ -440,7 +439,7 @@ static inline int alloc_subdevices(comedi_device * dev,
        for (i = 0; i < num_subdevices; ++i) {
                dev->subdevices[i].device = dev;
                dev->subdevices[i].async_dma_dir = DMA_NONE;
-               spin_lock_init(&dev->subdevices[i].runflags_lock);
+               spin_lock_init(&dev->subdevices[i].spin_lock);
        }
        return 0;
 }