nfsd4: reshuffle lease-setting code to allow reuse

[safe/jmp/linux-2.6] / fs / char_dev.c

diff --git a/fs/char_dev.c b/fs/char_dev.c
index 68e510b..d6db933 100644 (file)
--- a/fs/char_dev.c
+++ b/fs/char_dev.c
@@ -13,7 +13,6 @@
 #include <linux/major.h>
 #include <linux/errno.h>
 #include <linux/module.h>
-#include <linux/smp_lock.h>
 #include <linux/seq_file.h>
 
 #include <linux/kobject.h>
@@ -22,9 +21,6 @@
 #include <linux/mutex.h>
 #include <linux/backing-dev.h>
 
-#ifdef CONFIG_KMOD
-#include <linux/kmod.h>
-#endif
 #include "internal.h"
 
 /*
@@ -35,6 +31,7 @@
  * - no readahead or I/O queue unplugging required
  */
 struct backing_dev_info directly_mappable_cdev_bdi = {
+       .name = "char",
        .capabilities   = (
 #ifdef CONFIG_MMU
                /* permit private copies of the data to be taken */
@@ -123,7 +120,7 @@ __register_chrdev_region(unsigned int major, unsigned int baseminor,
        cd->major = major;
        cd->baseminor = baseminor;
        cd->minorct = minorct;
-       strncpy(cd->name,name, 64);
+       strlcpy(cd->name, name, sizeof(cd->name));
 
        i = major_to_index(major);
 
@@ -241,8 +238,10 @@ int alloc_chrdev_region(dev_t *dev, unsigned baseminor, unsigned count,
 }
 
 /**
- * register_chrdev() - Register a major number for character devices.
+ * __register_chrdev() - create and register a cdev occupying a range of minors
  * @major: major device number or 0 for dynamic allocation
+ * @baseminor: first of the requested range of minor numbers
+ * @count: the number of minor numbers required
  * @name: name of this range of devices
  * @fops: file operations associated with this devices
  *
@@ -258,19 +257,16 @@ int alloc_chrdev_region(dev_t *dev, unsigned baseminor, unsigned count,
  * /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)
+int __register_chrdev(unsigned int major, unsigned int baseminor,
+                     unsigned int count, const char *name,
+                     const struct file_operations *fops)
 {
        struct char_device_struct *cd;
        struct cdev *cdev;
-       char *s;
        int err = -ENOMEM;
 
-       cd = __register_chrdev_region(major, 0, 256, name);
+       cd = __register_chrdev_region(major, baseminor, count, name);
        if (IS_ERR(cd))
                return PTR_ERR(cd);
        
@@ -281,10 +277,8 @@ int register_chrdev(unsigned int major, const char *name,
        cdev->owner = fops->owner;
        cdev->ops = fops;
        kobject_set_name(&cdev->kobj, "%s", name);
-       for (s = strchr(kobject_name(&cdev->kobj),'/'); s; s = strchr(s, '/'))
-               *s = '!';
                
-       err = cdev_add(cdev, MKDEV(cd->major, 0), 256);
+       err = cdev_add(cdev, MKDEV(cd->major, baseminor), count);
        if (err)
                goto out;
 
@@ -294,7 +288,7 @@ int register_chrdev(unsigned int major, const char *name,
 out:
        kobject_put(&cdev->kobj);
 out2:
-       kfree(__unregister_chrdev_region(cd->major, 0, 256));
+       kfree(__unregister_chrdev_region(cd->major, baseminor, count));
        return err;
 }
 
@@ -320,10 +314,23 @@ void unregister_chrdev_region(dev_t from, unsigned count)
        }
 }
 
-void unregister_chrdev(unsigned int major, const char *name)
+/**
+ * __unregister_chrdev - unregister and destroy a cdev
+ * @major: major device number
+ * @baseminor: first of the range of minor numbers
+ * @count: the number of minor numbers this cdev is occupying
+ * @name: name of this range of devices
+ *
+ * Unregister and destroy the cdev occupying the region described by
+ * @major, @baseminor and @count.  This function undoes what
+ * __register_chrdev() did.
+ */
+void __unregister_chrdev(unsigned int major, unsigned int baseminor,
+                        unsigned int count, const char *name)
 {
        struct char_device_struct *cd;
-       cd = __unregister_chrdev_region(major, 0, 256);
+
+       cd = __unregister_chrdev_region(major, baseminor, count);
        if (cd && cd->cdev)
                cdev_del(cd->cdev);
        kfree(cd);
@@ -373,10 +380,11 @@ static int chrdev_open(struct inode *inode, struct file *filp)
                        return -ENXIO;
                new = container_of(kobj, struct cdev, kobj);
                spin_lock(&cdev_lock);
+               /* Check i_cdev again in case somebody beat us to it while
+                  we dropped the lock. */
                p = inode->i_cdev;
                if (!p) {
                        inode->i_cdev = p = new;
-                       inode->i_cindex = idx;
                        list_add(&inode->i_devices, &p->list);
                        new = NULL;
                } else if (!cdev_get(p))
@@ -387,21 +395,37 @@ static int chrdev_open(struct inode *inode, struct file *filp)
        cdev_put(new);
        if (ret)
                return ret;
+
+       ret = -ENXIO;
        filp->f_op = fops_get(p->ops);
-       if (!filp->f_op) {
-               cdev_put(p);
-               return -ENXIO;
-       }
+       if (!filp->f_op)
+               goto out_cdev_put;
+
        if (filp->f_op->open) {
-               lock_kernel();
                ret = filp->f_op->open(inode,filp);
-               unlock_kernel();
+               if (ret)
+                       goto out_cdev_put;
        }
-       if (ret)
-               cdev_put(p);
+
+       return 0;
+
+ out_cdev_put:
+       cdev_put(p);
        return ret;
 }
 
+int cdev_index(struct inode *inode)
+{
+       int idx;
+       struct kobject *kobj;
+
+       kobj = kobj_lookup(cdev_map, inode->i_rdev, &idx);
+       if (!kobj)
+               return -1;
+       kobject_put(kobj);
+       return idx;
+}
+
 void cd_forget(struct inode *inode)
 {
        spin_lock(&cdev_lock);
@@ -554,6 +578,7 @@ EXPORT_SYMBOL(cdev_init);
 EXPORT_SYMBOL(cdev_alloc);
 EXPORT_SYMBOL(cdev_del);
 EXPORT_SYMBOL(cdev_add);
-EXPORT_SYMBOL(register_chrdev);
-EXPORT_SYMBOL(unregister_chrdev);
+EXPORT_SYMBOL(cdev_index);
+EXPORT_SYMBOL(__register_chrdev);
+EXPORT_SYMBOL(__unregister_chrdev);
 EXPORT_SYMBOL(directly_mappable_cdev_bdi);