X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=fs%2Fchar_dev.c;h=0009346d827f52ad2da3c24bdbb6485d5cdfa6dd;hb=0a85b964e141a4b8db6eaf500ceace12f8f52f93;hp=4e1b849f912f740d6d120fe02abab1a347f53035;hpb=e21a2b0cc5849e76434b37aff3a4b502c772f191;p=pandora-kernel.git

diff --git a/fs/char_dev.c b/fs/char_dev.c
index 4e1b849f912f..0009346d827f 100644
--- a/fs/char_dev.c
+++ b/fs/char_dev.c
@@ -4,7 +4,6 @@
  *  Copyright (C) 1991, 1992  Linus Torvalds
  */
 
-#include <linux/config.h>
 #include <linux/init.h>
 #include <linux/fs.h>
 #include <linux/slab.h>
@@ -14,20 +13,37 @@
 #include <linux/errno.h>
 #include <linux/module.h>
 #include <linux/smp_lock.h>
-#include <linux/devfs_fs_kernel.h>
+#include <linux/seq_file.h>
 
 #include <linux/kobject.h>
 #include <linux/kobj_map.h>
 #include <linux/cdev.h>
 #include <linux/mutex.h>
+#include <linux/backing-dev.h>
 
 #ifdef CONFIG_KMOD
 #include <linux/kmod.h>
 #endif
 
-static struct kobj_map *cdev_map;
+/*
+ * capabilities for /dev/mem, /dev/kmem and similar directly mappable character
+ * devices
+ * - permits shared-mmap for read, write and/or exec
+ * - does not permit private mmap in NOMMU mode (can't do COW)
+ * - no readahead or I/O queue unplugging required
+ */
+struct backing_dev_info directly_mappable_cdev_bdi = {
+	.capabilities	= (
+#ifdef CONFIG_MMU
+		/* permit private copies of the data to be taken */
+		BDI_CAP_MAP_COPY |
+#endif
+		/* permit direct mmap, for read, write or exec */
+		BDI_CAP_MAP_DIRECT |
+		BDI_CAP_READ_MAP | BDI_CAP_WRITE_MAP | BDI_CAP_EXEC_MAP),
+};
 
-#define MAX_PROBE_HASH 255	/* random */
+static struct kobj_map *cdev_map;
 
 static DEFINE_MUTEX(chrdevs_lock);
 
@@ -39,93 +55,29 @@ static struct char_device_struct {
 	char name[64];
 	struct file_operations *fops;
 	struct cdev *cdev;		/* will die */
-} *chrdevs[MAX_PROBE_HASH];
+} *chrdevs[CHRDEV_MAJOR_HASH_SIZE];
 
 /* index in the above */
 static inline int major_to_index(int major)
 {
-	return major % MAX_PROBE_HASH;
+	return major % CHRDEV_MAJOR_HASH_SIZE;
 }
 
-struct chrdev_info {
-	int index;
-	struct char_device_struct *cd;
-};
+#ifdef CONFIG_PROC_FS
 
-void *get_next_chrdev(void *dev)
-{
-	struct chrdev_info *info;
-
-	if (dev == NULL) {
-		info = kmalloc(sizeof(*info), GFP_KERNEL);
-		if (!info)
-			goto out;
-		info->index=0;
-		info->cd = chrdevs[info->index];
-		if (info->cd)
-			goto out;
-	} else {
-		info = dev;
-	}
-
-	while (info->index < ARRAY_SIZE(chrdevs)) {
-		if (info->cd)
-			info->cd = info->cd->next;
-		if (info->cd)
-			goto out;
-		/*
-		 * No devices on this chain, move to the next
-		 */
-		info->index++;
-		info->cd = (info->index < ARRAY_SIZE(chrdevs)) ?
-			chrdevs[info->index] : NULL;
-		if (info->cd)
-			goto out;
-	}
-
-out:
-	return info;
-}
-
-void *acquire_chrdev_list(void)
-{
-	mutex_lock(&chrdevs_lock);
-	return get_next_chrdev(NULL);
-}
-
-void release_chrdev_list(void *dev)
-{
-	mutex_unlock(&chrdevs_lock);
-	kfree(dev);
-}
-
-
-int count_chrdev_list(void)
+void chrdev_show(struct seq_file *f, off_t offset)
 {
 	struct char_device_struct *cd;
-	int i, count;
-
-	count = 0;
 
-	for (i = 0; i < ARRAY_SIZE(chrdevs) ; i++) {
-		for (cd = chrdevs[i]; cd; cd = cd->next)
-			count++;
+	if (offset < CHRDEV_MAJOR_HASH_SIZE) {
+		mutex_lock(&chrdevs_lock);
+		for (cd = chrdevs[offset]; cd; cd = cd->next)
+			seq_printf(f, "%3d %s\n", cd->major, cd->name);
+		mutex_unlock(&chrdevs_lock);
 	}
-
-	return count;
 }
 
-int get_chrdev_info(void *dev, int *major, char **name)
-{
-	struct chrdev_info *info = dev;
-
-	if (info->cd == NULL)
-		return 1;
-
-	*major = info->cd->major;
-	*name = info->cd->name;
-	return 0;
-}
+#endif /* CONFIG_PROC_FS */
 
 /*
  * Register a single major with a specified minor range.
@@ -249,6 +201,28 @@ int alloc_chrdev_region(dev_t *dev, unsigned baseminor, unsigned count,
 	return 0;
 }
 
+/**
+ * register_chrdev() - Register a major number for character devices.
+ * @major: major device number or 0 for dynamic allocation
+ * @name: name of this range of devices
+ * @fops: file operations associated with this devices
+ *
+ * If @major == 0 this functions will dynamically allocate a major and return
+ * its number.
+ *
+ * If @major > 0 this function will attempt to reserve a device with the given
+ * major number and will return zero on success.
+ *
+ * Returns a -ve errno on failure.
+ *
+ * The name of this device has nothing to do with the name of the device in
+ * /dev. It only helps to keep track of the different owners of devices. If
+ * your module name has only one type of devices it's ok to use e.g. the name
+ * of the module here.
+ *
+ * This function registers a range of 256 minor numbers. The first minor number
+ * is 0.
+ */
 int register_chrdev(unsigned int major, const char *name,
 		    const struct file_operations *fops)
 {
@@ -506,3 +480,4 @@ EXPORT_SYMBOL(cdev_del);
 EXPORT_SYMBOL(cdev_add);
 EXPORT_SYMBOL(register_chrdev);
 EXPORT_SYMBOL(unregister_chrdev);
+EXPORT_SYMBOL(directly_mappable_cdev_bdi);