Allow setting of number of raw devices as a module parameter

Allow setting of maximal number of raw devices as a module parameter. This
requires changing of static array into a vmalloced one (the array is going to
be too large for kmalloc).

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 27 insertions, 6 deletions

diff --git a/drivers/char/raw.c b/drivers/char/raw.c
index b4b9d5a47885..6f9db621155a 100644
--- a/drivers/char/raw.c
+++ b/drivers/char/raw.c
@@ -21,6 +21,7 @@
 #include <linux/mutex.h>
 #include <linux/gfp.h>
 #include <linux/compat.h>
+#include <linux/vmalloc.h>
 
 #include <asm/uaccess.h>
 
@@ -30,10 +31,15 @@ struct raw_device_data {
 };
 
 static struct class *raw_class;
-static struct raw_device_data raw_devices[MAX_RAW_MINORS];
+static struct raw_device_data *raw_devices;
 static DEFINE_MUTEX(raw_mutex);
 static const struct file_operations raw_ctl_fops; /* forward declaration */
 
+static int max_raw_minors = MAX_RAW_MINORS;
+
+module_param(max_raw_minors, int, 0);
+MODULE_PARM_DESC(max_raw_minors, "Maximum number of raw devices (1-65536)");
+
 /*
  * Open/close code for raw IO.
  *
@@ -125,7 +131,7 @@ static int bind_set(int number, u64 major, u64 minor)
         struct raw_device_data *rawdev;
         int err = 0;
 
-        if (number <= 0 || number >= MAX_RAW_MINORS)
+        if (number <= 0 || number >= max_raw_minors)
                 return -EINVAL;
 
         if (MAJOR(dev) != major || MINOR(dev) != minor)
@@ -312,12 +318,26 @@ static int __init raw_init(void)
         dev_t dev = MKDEV(RAW_MAJOR, 0);
         int ret;
 
-        ret = register_chrdev_region(dev, MAX_RAW_MINORS, "raw");
+        if (max_raw_minors < 1 || max_raw_minors > 65536) {
+                printk(KERN_WARNING "raw: invalid max_raw_minors (must be"
+                        " between 1 and 65536), using %d\n", MAX_RAW_MINORS);
+                max_raw_minors = MAX_RAW_MINORS;
+        }
+
+        raw_devices = vmalloc(sizeof(struct raw_device_data) * max_raw_minors);
+        if (!raw_devices) {
+                printk(KERN_ERR "Not enough memory for raw device structures\n");
+                ret = -ENOMEM;
+                goto error;
+        }
+        memset(raw_devices, 0, sizeof(struct raw_device_data) * max_raw_minors);
+
+        ret = register_chrdev_region(dev, max_raw_minors, "raw");
         if (ret)
                 goto error;
 
         cdev_init(&raw_cdev, &raw_fops);
-        ret = cdev_add(&raw_cdev, dev, MAX_RAW_MINORS);
+        ret = cdev_add(&raw_cdev, dev, max_raw_minors);
         if (ret) {
                 kobject_put(&raw_cdev.kobj);
                 goto error_region;
@@ -336,8 +356,9 @@ static int __init raw_init(void)
         return 0;
 
 error_region:
-        unregister_chrdev_region(dev, MAX_RAW_MINORS);
+        unregister_chrdev_region(dev, max_raw_minors);
 error:
+        vfree(raw_devices);
         return ret;
 }
 
@@ -346,7 +367,7 @@ static void __exit raw_exit(void)
         device_destroy(raw_class, MKDEV(RAW_MAJOR, 0));
         class_destroy(raw_class);
         cdev_del(&raw_cdev);
-        unregister_chrdev_region(MKDEV(RAW_MAJOR, 0), MAX_RAW_MINORS);
+        unregister_chrdev_region(MKDEV(RAW_MAJOR, 0), max_raw_minors);
 }
 
 module_init(raw_init);