staging: comedi: change comedi_file_info_table_lock to mutex

The spin-lock `comedi_file_info_table_lock` is used to protect against
simultaneous modification and access of `comedi_file_info_table[]`.
Change it from a spin-lock to a mutex as it is only used in contexts
where sleeping is allowed.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c
index b3e5337591748e588ad9a903144b98be6d9c1e93..873860ff8bc15dcdd9d6e1632d58ed11c9addfdd 100644 (file)
--- a/drivers/staging/comedi/comedi_fops.c
+++ b/drivers/staging/comedi/comedi_fops.c
@@ -84,7 +84,7 @@ struct comedi_file_info {
        struct device *hardware_device;
 };
 
-static DEFINE_SPINLOCK(comedi_file_info_table_lock);
+static DEFINE_MUTEX(comedi_file_info_table_lock);
 static struct comedi_file_info *comedi_file_info_table[COMEDI_NUM_MINORS];
 
 static struct class *comedi_class;
@@ -121,10 +121,10 @@ static struct comedi_file_info *comedi_clear_minor(unsigned minor)
 {
        struct comedi_file_info *info;
 
-       spin_lock(&comedi_file_info_table_lock);
+       mutex_lock(&comedi_file_info_table_lock);
        info = comedi_file_info_table[minor];
        comedi_file_info_table[minor] = NULL;
-       spin_unlock(&comedi_file_info_table_lock);
+       mutex_unlock(&comedi_file_info_table_lock);
        return info;
 }
 
@@ -149,9 +149,9 @@ static struct comedi_file_info *comedi_file_info_from_minor(unsigned minor)
        struct comedi_file_info *info;
 
        BUG_ON(minor >= COMEDI_NUM_MINORS);
-       spin_lock(&comedi_file_info_table_lock);
+       mutex_lock(&comedi_file_info_table_lock);
        info = comedi_file_info_table[minor];
-       spin_unlock(&comedi_file_info_table_lock);
+       mutex_unlock(&comedi_file_info_table_lock);
        return info;
 }
 
@@ -2328,7 +2328,7 @@ struct comedi_device *comedi_alloc_board_minor(struct device *hardware_device)
        comedi_device_init(dev);
        comedi_set_hw_dev(dev, hardware_device);
        mutex_lock(&dev->mutex);
-       spin_lock(&comedi_file_info_table_lock);
+       mutex_lock(&comedi_file_info_table_lock);
        for (i = hardware_device ? comedi_num_legacy_minors : 0;
             i < COMEDI_NUM_BOARD_MINORS; ++i) {
                if (comedi_file_info_table[i] == NULL) {
@@ -2336,7 +2336,7 @@ struct comedi_device *comedi_alloc_board_minor(struct device *hardware_device)
                        break;
                }
        }
-       spin_unlock(&comedi_file_info_table_lock);
+       mutex_unlock(&comedi_file_info_table_lock);
        if (i == COMEDI_NUM_BOARD_MINORS) {
                mutex_unlock(&dev->mutex);
                comedi_device_cleanup(dev);
@@ -2369,15 +2369,15 @@ void comedi_release_hardware_device(struct device *hardware_device)
 
        for (minor = comedi_num_legacy_minors; minor < COMEDI_NUM_BOARD_MINORS;
             minor++) {
-               spin_lock(&comedi_file_info_table_lock);
+               mutex_lock(&comedi_file_info_table_lock);
                info = comedi_file_info_table[minor];
                if (info && info->hardware_device == hardware_device) {
                        comedi_file_info_table[minor] = NULL;
-                       spin_unlock(&comedi_file_info_table_lock);
+                       mutex_unlock(&comedi_file_info_table_lock);
                        comedi_free_board_file_info(info);
                        break;
                }
-               spin_unlock(&comedi_file_info_table_lock);
+               mutex_unlock(&comedi_file_info_table_lock);
        }
 }
 
@@ -2396,14 +2396,14 @@ int comedi_alloc_subdevice_minor(struct comedi_subdevice *s)
                info->read_subdevice = s;
        if (s->subdev_flags & SDF_CMD_WRITE)
                info->write_subdevice = s;
-       spin_lock(&comedi_file_info_table_lock);
+       mutex_lock(&comedi_file_info_table_lock);
        for (i = COMEDI_FIRST_SUBDEVICE_MINOR; i < COMEDI_NUM_MINORS; ++i) {
                if (comedi_file_info_table[i] == NULL) {
                        comedi_file_info_table[i] = info;
                        break;
                }
        }
-       spin_unlock(&comedi_file_info_table_lock);
+       mutex_unlock(&comedi_file_info_table_lock);
        if (i == COMEDI_NUM_MINORS) {
                kfree(info);
                pr_err("comedi: error: ran out of minor numbers for subdevice files.\n");