The use of umode_t instead of devfs-specific char vs block #defines
in Adam's mini-devfs patch makes sense independant of whether his patch
should get merged. While reviewing his changes I also notices that
most of the number allocation functionality in devfs has no business
beeing exported. In addition I cleaned up devfs_alloc_devnum/
devfs_dealloc_devnum a bit.
--- 1.68/fs/devfs/base.c Wed Jan 1 15:24:48 2003
+++ edited/fs/devfs/base.c Sat Jan 11 16:47:27 2003
@@ -685,6 +685,8 @@
#include <asm/bitops.h>
#include <asm/atomic.h>
+#include "internal.h"
+
#define DEVFS_VERSION "1.22 (20021013)"
#define DEVFS_NAME "devfs"
@@ -935,9 +937,9 @@
de->parent ? de->parent->name : "no parent");
if ( S_ISLNK (de->mode) ) kfree (de->u.symlink.linkname);
if ( S_ISCHR (de->mode) && de->u.cdev.autogen )
- devfs_dealloc_devnum (DEVFS_SPECIAL_CHR, de->u.cdev.dev);
+ devfs_dealloc_devnum (de->mode, de->u.cdev.dev);
if ( S_ISBLK (de->mode) && de->u.bdev.autogen )
- devfs_dealloc_devnum(DEVFS_SPECIAL_BLK, de->u.bdev.dev);
+ devfs_dealloc_devnum (de->mode, de->u.bdev.dev);
WRITE_ENTRY_MAGIC (de, 0);
#ifdef CONFIG_DEVFS_DEBUG
spin_lock (&stat_lock);
@@ -1102,13 +1104,13 @@
/* And create the entry for ".devfsd" */
if ( ( new = _devfs_alloc_entry (".devfsd", 0, S_IFCHR |S_IRUSR |S_IWUSR) )
== NULL ) return NULL;
- new->u.cdev.dev = devfs_alloc_devnum (DEVFS_SPECIAL_CHR);
+ new->u.cdev.dev = devfs_alloc_devnum (S_IFCHR |S_IRUSR |S_IWUSR);
new->u.cdev.ops = &devfsd_fops;
_devfs_append_entry (root_entry, new, FALSE, NULL);
#ifdef CONFIG_DEVFS_DEBUG
if ( ( new = _devfs_alloc_entry (".stat", 0, S_IFCHR | S_IRUGO | S_IWUGO) )
== NULL ) return NULL;
- new->u.cdev.dev = devfs_alloc_devnum (DEVFS_SPECIAL_CHR);
+ new->u.cdev.dev = devfs_alloc_devnum (S_IFCHR | S_IRUGO | S_IWUGO);
new->u.cdev.ops = &stat_fops;
_devfs_append_entry (root_entry, new, FALSE, NULL);
#endif
@@ -1469,7 +1471,6 @@
unsigned int major, unsigned int minor,
umode_t mode, void *ops, void *info)
{
- char devtype = S_ISCHR (mode) ? DEVFS_SPECIAL_CHR : DEVFS_SPECIAL_BLK;
int err;
dev_t devnum = 0, dev = MKDEV(major, minor);
struct devfs_entry *de;
@@ -1497,7 +1498,7 @@
if ( ( S_ISCHR (mode) || S_ISBLK (mode) ) &&
(flags & DEVFS_FL_AUTO_DEVNUM) )
{
- devnum = devfs_alloc_devnum (devtype);
+ devnum = devfs_alloc_devnum (mode);
if (!devnum) {
PRINTK ("(%s): exhausted %s device numbers\n",
name, S_ISCHR (mode) ? "char" : "block");
@@ -1508,7 +1509,7 @@
if ( ( de = _devfs_prepare_leaf (&dir, name, mode) ) == NULL )
{
PRINTK ("(%s): could not prepare leaf\n", name);
- if (devnum) devfs_dealloc_devnum (devtype, devnum);
+ if (devnum) devfs_dealloc_devnum (mode, devnum);
return NULL;
}
if (S_ISCHR (mode)) {
@@ -1544,7 +1545,7 @@
{
PRINTK ("(%s): could not append to parent, err: %d\n", name, err);
devfs_put (dir);
- if (devnum) devfs_dealloc_devnum (devtype, devnum);
+ if (devnum) devfs_dealloc_devnum (mode, devnum);
return NULL;
}
DPRINTK (DEBUG_REGISTER, "(%s): de: %p dir: %p \"%s\" pp: %p\n",
@@ -1953,7 +1954,6 @@
EXPORT_SYMBOL(devfs_mk_dir);
EXPORT_SYMBOL(devfs_remove);
EXPORT_SYMBOL(devfs_generate_path);
-EXPORT_SYMBOL(devfs_only);
/**
===== fs/devfs/util.c 1.16 vs edited =====
--- 1.16/fs/devfs/util.c Tue Dec 3 13:26:32 2002
+++ edited/fs/devfs/util.c Sat Jan 11 17:57:50 2003
@@ -60,14 +60,16 @@
Copied and used macro for error messages from fs/devfs/base.c
20021013 Richard Gooch <[email protected]>
Documentation fix.
+ 20030101 Adam J. Richter <[email protected]>
+ Eliminate DEVFS_SPECIAL_{CHR,BLK}. Use umode_t instead.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/devfs_fs_kernel.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
-
#include <asm/bitops.h>
+#include "internal.h"
#define PRINTK(format, args...) \
{printk (KERN_ERR "%s" format, __FUNCTION__ , ## args);}
@@ -145,49 +147,11 @@
/**
* devfs_alloc_major - Allocate a major number.
- * @type: The type of the major (DEVFS_SPECIAL_CHR or DEVFS_SPECIAL_BLK)
-
+ * @mode: The file mode (must be block device or character device).
* Returns the allocated major, else -1 if none are available.
* This routine is thread safe and does not block.
*/
-int devfs_alloc_major (char type)
-{
- int major;
- struct major_list *list;
-
- list = (type == DEVFS_SPECIAL_CHR) ? &char_major_list : &block_major_list;
- spin_lock (&list->lock);
- major = find_first_zero_bit (list->bits, 256);
- if (major < 256) __set_bit (major, list->bits);
- else major = -1;
- spin_unlock (&list->lock);
- return major;
-} /* End Function devfs_alloc_major */
-EXPORT_SYMBOL(devfs_alloc_major);
-
-
-/**
- * devfs_dealloc_major - Deallocate a major number.
- * @type: The type of the major (DEVFS_SPECIAL_CHR or DEVFS_SPECIAL_BLK)
- * @major: The major number.
- * This routine is thread safe and does not block.
- */
-
-void devfs_dealloc_major (char type, int major)
-{
- int was_set;
- struct major_list *list;
-
- if (major < 0) return;
- list = (type == DEVFS_SPECIAL_CHR) ? &char_major_list : &block_major_list;
- spin_lock (&list->lock);
- was_set = __test_and_clear_bit (major, list->bits);
- spin_unlock (&list->lock);
- if (!was_set) PRINTK ("(): major %d was already free\n", major);
-} /* End Function devfs_dealloc_major */
-EXPORT_SYMBOL(devfs_dealloc_major);
-
struct minor_list
{
@@ -196,130 +160,110 @@
struct minor_list *next;
};
-struct device_list
-{
- struct minor_list *first, *last;
- int none_free;
-};
-
-static DECLARE_MUTEX (block_semaphore);
-static struct device_list block_list;
+static struct device_list {
+ struct minor_list *first;
+ struct minor_list *last;
+ int none_free;
+} block_list, char_list;
-static DECLARE_MUTEX (char_semaphore);
-static struct device_list char_list;
+static DECLARE_MUTEX(device_list_mutex);
/**
* devfs_alloc_devnum - Allocate a device number.
- * @type: The type (DEVFS_SPECIAL_CHR or DEVFS_SPECIAL_BLK).
+ * @mode: The file mode (must be block device or character device).
*
* Returns the allocated device number, else NODEV if none are available.
* This routine is thread safe and may block.
*/
-dev_t devfs_alloc_devnum (char type)
+dev_t devfs_alloc_devnum(umode_t mode)
{
- int minor;
- struct semaphore *semaphore;
- struct device_list *list;
- struct minor_list *entry;
-
- if (type == DEVFS_SPECIAL_CHR)
- {
- semaphore = &char_semaphore;
- list = &char_list;
- }
- else
- {
- semaphore = &block_semaphore;
- list = &block_list;
- }
- if (list->none_free) return 0; /* Fast test */
- down (semaphore);
- if (list->none_free)
- {
- up (semaphore);
- return 0;
- }
- for (entry = list->first; entry != NULL; entry = entry->next)
- {
- minor = find_first_zero_bit (entry->bits, 256);
- if (minor >= 256) continue;
- __set_bit (minor, entry->bits);
- up (semaphore);
+ struct device_list *list;
+ struct major_list *major_list;
+ struct minor_list *entry;
+ int minor;
+
+ if (S_ISCHR(mode)) {
+ major_list = &char_major_list;
+ list = &char_list;
+ } else {
+ major_list = &block_major_list;
+ list = &block_list;
+ }
+
+ down(&device_list_mutex);
+ if (list->none_free)
+ goto out_unlock;
+
+ for (entry = list->first; entry; entry = entry->next) {
+ minor = find_first_zero_bit (entry->bits, 256);
+ if (minor >= 256)
+ continue;
+ goto out_done;
+ }
+
+ /* Need to allocate a new major */
+ entry = kmalloc (sizeof *entry, GFP_KERNEL);
+ if (!entry)
+ goto out_full;
+ memset(entry, 0, sizeof *entry);
+
+ spin_lock(&major_list->lock);
+ entry->major = find_first_zero_bit(major_list->bits, 256);
+ if (entry->major >= 256) {
+ spin_unlock(&major_list->lock);
+ kfree(entry);
+ goto out_full;
+ }
+ __set_bit(entry->major, major_list->bits);
+ spin_unlock(&major_list->lock);
+
+ if (!list->first)
+ list->first = entry;
+ else
+ list->last->next = entry;
+ list->last = entry;
+
+ minor = 0;
+ out_done:
+ __set_bit(minor, entry->bits);
+ up(&device_list_mutex);
return MKDEV(entry->major, minor);
- }
- /* Need to allocate a new major */
- if ( ( entry = kmalloc (sizeof *entry, GFP_KERNEL) ) == NULL )
- {
- list->none_free = 1;
- up (semaphore);
- return 0;
- }
- memset (entry, 0, sizeof *entry);
- if ( ( entry->major = devfs_alloc_major (type) ) < 0 )
- {
+ out_full:
list->none_free = 1;
- up (semaphore);
- kfree (entry);
+ out_unlock:
+ up(&device_list_mutex);
return 0;
- }
- __set_bit (0, entry->bits);
- if (list->first == NULL) list->first = entry;
- else list->last->next = entry;
- list->last = entry;
- up (semaphore);
- return MKDEV(entry->major, 0);
-} /* End Function devfs_alloc_devnum */
-EXPORT_SYMBOL(devfs_alloc_devnum);
+}
/**
* devfs_dealloc_devnum - Dellocate a device number.
- * @type: The type (DEVFS_SPECIAL_CHR or DEVFS_SPECIAL_BLK).
+ * @mode: The file mode (must be block device or character device).
* @devnum: The device number.
*
* This routine is thread safe and may block.
*/
-void devfs_dealloc_devnum (char type, dev_t devnum)
+void devfs_dealloc_devnum(umode_t mode, dev_t devnum)
{
- int major, minor;
- struct semaphore *semaphore;
- struct device_list *list;
- struct minor_list *entry;
-
- if (!devnum) return;
- if (type == DEVFS_SPECIAL_CHR)
- {
- semaphore = &char_semaphore;
- list = &char_list;
- }
- else
- {
- semaphore = &block_semaphore;
- list = &block_list;
- }
- major = MAJOR (devnum);
- minor = MINOR (devnum);
- down (semaphore);
- for (entry = list->first; entry != NULL; entry = entry->next)
- {
- int was_set;
-
- if (entry->major != major) continue;
- was_set = __test_and_clear_bit (minor, entry->bits);
- if (was_set) list->none_free = 0;
- up (semaphore);
- if (!was_set)
- PRINTK ( "(): device %s was already free\n", kdevname (to_kdev_t(devnum)) );
- return;
- }
- up (semaphore);
- PRINTK ( "(): major for %s not previously allocated\n",
- kdevname (to_kdev_t(devnum)) );
-} /* End Function devfs_dealloc_devnum */
-EXPORT_SYMBOL(devfs_dealloc_devnum);
+ struct device_list *list = S_ISCHR(mode) ? &char_list : &block_list;
+ struct minor_list *entry;
+
+ if (!devnum)
+ return;
+
+ down(&device_list_mutex);
+ for (entry = list->first; entry; entry = entry->next) {
+ if (entry->major == MAJOR(devnum)) {
+ if (__test_and_clear_bit(MINOR(devnum), entry->bits))
+ list->none_free = 0;
+ break;
+ }
+ }
+ up(&device_list_mutex);
+}
/**
--- /dev/null 2002-08-30 19:31:37.000000000 -0400
+++ edited/fs/devfs/internal.h 2003-01-11 16:44:54.000000000 -0500
@@ -0,0 +1,3 @@
+
+extern dev_t devfs_alloc_devnum(umode_t mode);
+extern void devfs_dealloc_devnum(umode_t mode, dev_t devnum);
--- 1.27/include/linux/devfs_fs_kernel.h Wed Jan 1 15:18:35 2003
+++ edited/include/linux/devfs_fs_kernel.h Sat Jan 11 16:47:08 2003
@@ -21,9 +21,6 @@
#define DEVFS_FL_DEFAULT DEVFS_FL_NONE
-#define DEVFS_SPECIAL_CHR 0
-#define DEVFS_SPECIAL_BLK 1
-
typedef struct devfs_entry * devfs_handle_t;
#ifdef CONFIG_DEVFS_FS
@@ -58,10 +55,6 @@
extern int devfs_only (void);
extern int devfs_register_tape (devfs_handle_t de);
extern void devfs_unregister_tape(int num);
-extern int devfs_alloc_major (char type);
-extern void devfs_dealloc_major (char type, int major);
-extern dev_t devfs_alloc_devnum (char type);
-extern void devfs_dealloc_devnum (char type, dev_t devnum);
extern int devfs_alloc_unique_number (struct unique_numspace *space);
extern void devfs_dealloc_unique_number (struct unique_numspace *space,
int number);
@@ -129,41 +122,18 @@
static inline void devfs_unregister_tape(int num)
{
}
-static inline int devfs_alloc_major (char type)
-{
- return -1;
-}
-
-static inline void devfs_dealloc_major (char type, int major)
-{
- return;
-}
-
-static inline dev_t devfs_alloc_devnum (char type)
-{
- return 0;
-}
-
-static inline void devfs_dealloc_devnum (char type, dev_t devnum)
-{
- return;
-}
-
static inline int devfs_alloc_unique_number (struct unique_numspace *space)
{
return -1;
}
-
static inline void devfs_dealloc_unique_number (struct unique_numspace *space,
int number)
{
return;
}
-
static inline void mount_devfs_fs (void)
{
return;
}
#endif /* CONFIG_DEVFS_FS */
-
#endif /* _LINUX_DEVFS_FS_KERNEL_H */
Christoph Hellwig wrote:
>The use of umode_t instead of devfs-specific char vs block #defines
>in Adam's mini-devfs patch makes sense independant of whether his patch
>should get merged. While reviewing his changes I also notices that
>most of the number allocation functionality in devfs has no business
>beeing exported. In addition I cleaned up devfs_alloc_devnum/
>devfs_dealloc_devnum a bit.
It looks good to me, although I haven't tried it or fully
comprehended every line of Christoph's devfs_{,de}alloc_devnum cleanup
(I have looked at it a bit before sending this email though).
One really minor suggestion: perhaps Christoph could add an
entry in the giant change log in fs/devfs/util.c so that people know
who to contact if there is a problem with his number allocation
change.
Adam J. Richter __ ______________ 575 Oroville Road
[email protected] \ / Milpitas, California 95035
+1 408 309-6081 | g g d r a s i l United States of America
"Free Software For The Rest Of Us."