NFS: Save padding bytes in struct nfs4_setclientid

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

diff --git a/fs/char_dev.c b/fs/char_dev.c
index 33b95af..3cb7cda 100644 (file)
--- a/fs/char_dev.c
+++ b/fs/char_dev.c
@@ -6,6 +6,7 @@
 
 #include <linux/init.h>
 #include <linux/fs.h>
+#include <linux/kdev_t.h>
 #include <linux/slab.h>
 #include <linux/string.h>
 
@@ -24,6 +25,7 @@
 #ifdef CONFIG_KMOD
 #include <linux/kmod.h>
 #endif
+#include "internal.h"
 
 /*
  * capabilities for /dev/mem, /dev/kmem and similar directly mappable character
@@ -53,7 +55,6 @@ static struct char_device_struct {
        unsigned int baseminor;
        int minorct;
        char name[64];
-       struct file_operations *fops;
        struct cdev *cdev;              /* will die */
 } *chrdevs[CHRDEV_MAJOR_HASH_SIZE];
 
@@ -183,6 +184,15 @@ __unregister_chrdev_region(unsigned major, unsigned baseminor, int minorct)
        return cd;
 }
 
+/**
+ * register_chrdev_region() - register a range of device numbers
+ * @from: the first in the desired range of device numbers; must include
+ *        the major number.
+ * @count: the number of consecutive device numbers required
+ * @name: the name of the device or driver.
+ *
+ * Return value is zero on success, a negative error code on failure.
+ */
 int register_chrdev_region(dev_t from, unsigned count, const char *name)
 {
        struct char_device_struct *cd;
@@ -208,6 +218,17 @@ fail:
        return PTR_ERR(cd);
 }
 
+/**
+ * alloc_chrdev_region() - register a range of char device numbers
+ * @dev: output parameter for first assigned number
+ * @baseminor: first of the requested range of minor numbers
+ * @count: the number of minor numbers required
+ * @name: the name of the associated device or driver
+ *
+ * Allocates a range of char device numbers.  The major number will be
+ * chosen dynamically, and returned (along with the first minor number)
+ * in @dev.  Returns zero or a negative error code.
+ */
 int alloc_chrdev_region(dev_t *dev, unsigned baseminor, unsigned count,
                        const char *name)
 {
@@ -277,6 +298,15 @@ out2:
        return err;
 }
 
+/**
+ * unregister_chrdev_region() - return a range of device numbers
+ * @from: the first in the range of numbers to unregister
+ * @count: the number of device numbers to unregister
+ *
+ * This function will unregister a range of @count device numbers,
+ * starting with @from.  The caller should normally be the one who
+ * allocated those numbers in the first place...
+ */
 void unregister_chrdev_region(dev_t from, unsigned count)
 {
        dev_t to = from + count;
@@ -290,14 +320,13 @@ void unregister_chrdev_region(dev_t from, unsigned count)
        }
 }
 
-int unregister_chrdev(unsigned int major, const char *name)
+void unregister_chrdev(unsigned int major, const char *name)
 {
        struct char_device_struct *cd;
        cd = __unregister_chrdev_region(major, 0, 256);
        if (cd && cd->cdev)
                cdev_del(cd->cdev);
        kfree(cd);
-       return 0;
 }
 
 static DEFINE_SPINLOCK(cdev_lock);
@@ -327,7 +356,7 @@ void cdev_put(struct cdev *p)
 /*
  * Called every time a character special file is opened
  */
-int chrdev_open(struct inode * inode, struct file * filp)
+static int chrdev_open(struct inode *inode, struct file *filp)
 {
        struct cdev *p;
        struct cdev *new = NULL;
@@ -344,6 +373,8 @@ 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;
@@ -363,11 +394,8 @@ int chrdev_open(struct inode * inode, struct file * filp)
                cdev_put(p);
                return -ENXIO;
        }
-       if (filp->f_op->open) {
-               lock_kernel();
+       if (filp->f_op->open)
                ret = filp->f_op->open(inode,filp);
-               unlock_kernel();
-       }
        if (ret)
                cdev_put(p);
        return ret;
@@ -414,6 +442,16 @@ static int exact_lock(dev_t dev, void *data)
        return cdev_get(p) ? 0 : -1;
 }
 
+/**
+ * cdev_add() - add a char device to the system
+ * @p: the cdev structure for the device
+ * @dev: the first device number for which this device is responsible
+ * @count: the number of consecutive minor numbers corresponding to this
+ *         device
+ *
+ * cdev_add() adds the device represented by @p to the system, making it
+ * live immediately.  A negative error code is returned on failure.
+ */
 int cdev_add(struct cdev *p, dev_t dev, unsigned count)
 {
        p->dev = dev;
@@ -426,6 +464,13 @@ static void cdev_unmap(dev_t dev, unsigned count)
        kobj_unmap(cdev_map, dev, count);
 }
 
+/**
+ * cdev_del() - remove a cdev from the system
+ * @p: the cdev structure to be removed
+ *
+ * cdev_del() removes @p from the system, possibly freeing the structure
+ * itself.
+ */
 void cdev_del(struct cdev *p)
 {
        cdev_unmap(p->dev, p->count);
@@ -454,23 +499,34 @@ static struct kobj_type ktype_cdev_dynamic = {
        .release        = cdev_dynamic_release,
 };
 
+/**
+ * cdev_alloc() - allocate a cdev structure
+ *
+ * Allocates and returns a cdev structure, or NULL on failure.
+ */
 struct cdev *cdev_alloc(void)
 {
        struct cdev *p = kzalloc(sizeof(struct cdev), GFP_KERNEL);
        if (p) {
-               p->kobj.ktype = &ktype_cdev_dynamic;
                INIT_LIST_HEAD(&p->list);
-               kobject_init(&p->kobj);
+               kobject_init(&p->kobj, &ktype_cdev_dynamic);
        }
        return p;
 }
 
+/**
+ * cdev_init() - initialize a cdev structure
+ * @cdev: the structure to initialize
+ * @fops: the file_operations for this device
+ *
+ * Initializes @cdev, remembering @fops, making it ready to add to the
+ * system with cdev_add().
+ */
 void cdev_init(struct cdev *cdev, const struct file_operations *fops)
 {
        memset(cdev, 0, sizeof *cdev);
        INIT_LIST_HEAD(&cdev->list);
-       cdev->kobj.ktype = &ktype_cdev_default;
-       kobject_init(&cdev->kobj);
+       kobject_init(&cdev->kobj, &ktype_cdev_default);
        cdev->ops = fops;
 }
 
@@ -485,6 +541,7 @@ static struct kobject *base_probe(dev_t dev, int *part, void *data)
 void __init chrdev_init(void)
 {
        cdev_map = kobj_map_init(base_probe, &chrdevs_lock);
+       bdi_init(&directly_mappable_cdev_bdi);
 }