[PATCH] devfs: gendisk.devfs_name updates

Previously gendisk.devfs_name was used only for partitioned devices
or CDroms, and for the latter it was slightly broken.  Fix it to
work genericly for all gendisks.

drivers/ide/ide-cd.c

@@ -3366,7 +3366,8 @@ static int ide_cdrom_attach (ide_drive_t *drive)
 	DRIVER(drive)->busy++;
 	g->minors = 1;
 	g->minor_shift = 0;
-	strcpy(g->devfs_name, drive->devfs_name);
+	snprintf(g->devfs_name, sizeof(g->devfs_name),
+			"%s/cd", drive->devfs_name);
 	g->driverfs_dev = &drive->gendev;
 	g->flags = GENHD_FL_CD;
 	if (ide_cdrom_setup(drive)) {

drivers/scsi/sr.c

@@ -569,7 +569,8 @@ static int sr_attach(struct scsi_device *sdev)
 	get_capabilities(cd);
 	sr_vendor_init(cd);
 
-	strcpy(disk->devfs_name, sdev->devfs_name);
+	snprintf(disk->devfs_name, sizeof(disk->devfs_name),
+			"%s/cd", sdev->devfs_name);
 	disk->driverfs_dev = &sdev->sdev_driverfs_dev;
 	register_cdrom(&cd->cdi);
 	set_capacity(disk, cd->capacity);

fs/devfs/util.c

@@ -74,8 +74,6 @@
 #include <asm/bitops.h>
 #include "internal.h"
 
-#define PRINTK(format, args...) \
-   {printk (KERN_ERR "%s" format, __FUNCTION__ , ## args);}
 
 int devfs_register_tape(const char *name)
 {
@@ -257,139 +255,6 @@ void devfs_dealloc_devnum(umode_t mode, dev_t devnum)
 	up(&device_list_mutex);
 }
 
-struct unique_numspace
-{
-    spinlock_t init_lock;
-    unsigned char sem_initialised;
-    unsigned int num_free;          /*  Num free in bits       */
-    unsigned int length;            /*  Array length in bytes  */
-    unsigned long *bits;
-    struct semaphore semaphore;
-};
-
-#define UNIQUE_NUMBERSPACE_INITIALISER {SPIN_LOCK_UNLOCKED, 0, 0, 0, NULL}
-
-
-/**
- *	devfs_alloc_unique_number - Allocate a unique (positive) number.
- *	@space: The number space to allocate from.
- *
- *	Returns the allocated unique number, else a negative error code.
- *	This routine is thread safe and may block.
- */
-
-int devfs_alloc_unique_number (struct unique_numspace *space)
-{
-    int number;
-    unsigned int length;
-
-    /*  Get around stupid lack of semaphore initialiser  */
-    spin_lock (&space->init_lock);
-    if (!space->sem_initialised)
-    {
-	sema_init (&space->semaphore, 1);
-	space->sem_initialised = 1;
-    }
-    spin_unlock (&space->init_lock);
-    down (&space->semaphore);
-    if (space->num_free < 1)
-    {
-	void *bits;
-
-	if (space->length < 16) length = 16;
-	else length = space->length << 1;
-	if ( ( bits = vmalloc (length) ) == NULL )
-	{
-	    up (&space->semaphore);
-	    return -ENOMEM;
-	}
-	if (space->bits != NULL)
-	{
-	    memcpy (bits, space->bits, space->length);
-	    vfree (space->bits);
-	}
-	space->num_free = (length - space->length) << 3;
-	space->bits = bits;
-	memset (bits + space->length, 0, length - space->length);
-	space->length = length;
-    }
-    number = find_first_zero_bit (space->bits, space->length << 3);
-    --space->num_free;
-    __set_bit (number, space->bits);
-    up (&space->semaphore);
-    return number;
-}   /*  End Function devfs_alloc_unique_number  */
-EXPORT_SYMBOL(devfs_alloc_unique_number);
-
-
-/**
- *	devfs_dealloc_unique_number - Deallocate a unique (positive) number.
- *	@space: The number space to deallocate from.
- *	@number: The number to deallocate.
- *
- *	This routine is thread safe and may block.
- */
-
-void devfs_dealloc_unique_number (struct unique_numspace *space, int number)
-{
-    int was_set;
-
-    if (number < 0) return;
-    down (&space->semaphore);
-    was_set = __test_and_clear_bit (number, space->bits);
-    if (was_set) ++space->num_free;
-    up (&space->semaphore);
-    if (!was_set) PRINTK ("(): number %d was already free\n", number);
-}   /*  End Function devfs_dealloc_unique_number  */
-EXPORT_SYMBOL(devfs_dealloc_unique_number);
-
-static struct unique_numspace disc_numspace = UNIQUE_NUMBERSPACE_INITIALISER;
-static struct unique_numspace cdrom_numspace = UNIQUE_NUMBERSPACE_INITIALISER;
-
-void devfs_create_partitions(struct gendisk *disk)
-{
-	char dirname[64], diskname[64], symlink[16];
-
-	if (!disk->devfs_name)
-		sprintf(disk->devfs_name, "%s/disc%d", disk->disk_name,
-				disk->first_minor >> disk->minor_shift);
-
-	devfs_mk_dir(disk->devfs_name);
-	disk->number = devfs_alloc_unique_number(&disc_numspace);
-
-	sprintf(diskname, "%s/disc", disk->devfs_name);
-	devfs_register(NULL, diskname, 0,
-			disk->major, disk->first_minor,
-			S_IFBLK | S_IRUSR | S_IWUSR,
-			disk->fops, NULL);
-
-	sprintf(symlink, "discs/disc%d", disk->number);
-	sprintf(dirname, "../%s", disk->devfs_name);
-	devfs_mk_symlink(symlink, dirname);
-
-}
-
-void devfs_create_cdrom(struct gendisk *disk)
-{
-	char dirname[64], cdname[64], symlink[16];
-
-	if (!disk->devfs_name)
-		strcat(disk->devfs_name, disk->disk_name);
-
-	devfs_mk_dir(disk->devfs_name);
-	disk->number = devfs_alloc_unique_number(&cdrom_numspace);
-
-	sprintf(cdname, "%s/cd", disk->devfs_name);
-	devfs_register(NULL, cdname, 0,
-			disk->major, disk->first_minor,
-			S_IFBLK | S_IRUGO | S_IWUGO,
-			disk->fops, NULL);
-
-	sprintf(symlink, "cdroms/cdrom%d", disk->number);
-	sprintf(dirname, "../%s", disk->devfs_name);
-	devfs_mk_symlink(symlink, dirname);
-}
-
 void devfs_register_partition(struct gendisk *dev, int part)
 {
 	char devname[64];
@@ -400,17 +265,3 @@ void devfs_register_partition(struct gendisk *dev, int part)
 			S_IFBLK | S_IRUSR | S_IWUSR,
 			dev->fops, NULL);
 }
-
-void devfs_remove_partitions(struct gendisk *disk)
-{
-	devfs_remove("discs/disc%d", disk->number);
-	devfs_remove(disk->devfs_name);
-	devfs_dealloc_unique_number(&disc_numspace, disk->number);
-}
-
-void devfs_remove_cdrom(struct gendisk *disk)
-{
-	devfs_remove("cdroms/cdrom%d", disk->number);
-	devfs_remove(disk->devfs_name);
-	devfs_dealloc_unique_number(&cdrom_numspace, disk->number);
-}

fs/partitions/Makefile

@@ -4,6 +4,7 @@
 
 obj-y := check.o
 
+obj-$(CONFIG_DEVFS_FS) += devfs.o
 obj-$(CONFIG_ACORN_PARTITION) += acorn.o
 obj-$(CONFIG_AMIGA_PARTITION) += amiga.o
 obj-$(CONFIG_ATARI_PARTITION) += atari.o

fs/partitions/check.c

@@ -19,8 +19,10 @@
 #include <linux/blk.h>
 #include <linux/kmod.h>
 #include <linux/ctype.h>
+#include <linux/devfs_fs_kernel.h>
 
 #include "check.h"
+#include "devfs.h"
 
 #include "acorn.h"
 #include "amiga.h"
@@ -94,25 +96,24 @@ static int (*check_part[])(struct parsed_partitions *, struct block_device *) =
 
 char *disk_name(struct gendisk *hd, int part, char *buf)
 {
-	if (!part) {
 #ifdef CONFIG_DEVFS_FS
-		if (hd->devfs_name)
-			sprintf(buf, "%s/%s", hd->devfs_name,
-				(hd->flags & GENHD_FL_CD) ? "cd" : "disc");
-		else
-#endif
-			sprintf(buf, "%s", hd->disk_name);
-	} else {
-#ifdef CONFIG_DEVFS_FS
-		if (hd->devfs_name)
+	if (hd->devfs_name[0] != '\0') {
+		if (part)
 			sprintf(buf, "%s/part%d", hd->devfs_name, part);
+		else if (hd->minors != 1)
+			sprintf(buf, "%s/disc", hd->devfs_name);
 		else
+			sprintf(buf, "%s", hd->devfs_name);
+		return buf;
+	}
 #endif
-		if (isdigit(hd->disk_name[strlen(hd->disk_name)-1]))
+
+	if (!part)
+		sprintf(buf, "%s", hd->disk_name);
+	else if (isdigit(hd->disk_name[strlen(hd->disk_name)-1]))
 		sprintf(buf, "%sp%d", hd->disk_name, part);
 	else
 		sprintf(buf, "%s%d", hd->disk_name, part);
-	}
 
 	return buf;
 }
@@ -128,7 +129,7 @@ check_partition(struct gendisk *hd, struct block_device *bdev)
 		return NULL;
 
 #ifdef CONFIG_DEVFS_FS
-	if (hd->devfs_name) {
+	if (hd->devfs_name[0] != '\0') {
 		printk(KERN_INFO " /dev/%s:", hd->devfs_name);
 		sprintf(state->name, "p");
 	}
@@ -284,12 +285,12 @@ void register_disk(struct gendisk *disk)
 		return;
 	disk_sysfs_symlinks(disk);
 
-	if (disk->flags & GENHD_FL_CD)
-		devfs_create_cdrom(disk);
-
 	/* No minors to use for partitions */
-	if (disk->minors == 1)
+	if (disk->minors == 1) {
+		if (disk->devfs_name[0] != '\0')
+			devfs_add_disk(disk);
 		return;
+	}
 
 	/* No such device (e.g., media were just removed) */
 	if (!get_capacity(disk))
@@ -299,7 +300,7 @@ void register_disk(struct gendisk *disk)
 	if (blkdev_get(bdev, FMODE_READ, 0, BDEV_RAW) < 0)
 		return;
 	state = check_partition(disk, bdev);
-	devfs_create_partitions(disk);
+	devfs_add_partitioned(disk);
 	if (state) {
 		for (j = 1; j < state->limit; j++) {
 			sector_t size = state->parts[j].size;
@@ -392,10 +393,9 @@ void del_gendisk(struct gendisk *disk)
 	unlink_gendisk(disk);
 	disk_stat_set_all(disk, 0);
 	disk->stamp = disk->stamp_idle = 0;
-	if (disk->flags & GENHD_FL_CD)
-		devfs_remove_cdrom(disk);
-	else
-		devfs_remove_partitions(disk);
+
+	devfs_remove_disk(disk);
+
 	if (disk->driverfs_dev) {
 		sysfs_remove_link(&disk->kobj, "device");
 		sysfs_remove_link(&disk->driverfs_dev->kobj, "block");

fs/partitions/devfs.c

+/*
+ * This tries to keep block devices away from devfs as much as possible.
+ */
+#include <linux/fs.h>
+#include <linux/devfs_fs_kernel.h>
+#include <linux/vmalloc.h>
+#include <linux/genhd.h>
+#include <asm/bitops.h>
+#include <asm/semaphore.h>
+
+
+struct unique_numspace {
+	u32		  num_free;          /*  Num free in bits       */
+	u32		  length;            /*  Array length in bytes  */
+	unsigned long	  *bits;
+	struct semaphore  mutex;
+};
+
+static DECLARE_MUTEX(numspace_mutex);
+
+static int expand_numspace(struct unique_numspace *s)
+{
+	u32 length;
+	void *bits;
+
+	if (s->length < 16)
+		length = 16;
+	else
+		length = s->length << 1;
+
+	bits = vmalloc(length);
+	if (!bits)
+		return -ENOMEM;
+	if (s->bits) {
+		memcpy(bits, s->bits, s->length);
+		vfree(s->bits);
+	}
+		
+	s->num_free = (length - s->length) << 3;
+	s->bits = bits;
+	memset(bits + s->length, 0, length - s->length);
+	s->length = length;
+
+	return 0;
+}
+
+static int alloc_unique_number(struct unique_numspace *s)
+{
+	int rval = 0;
+
+	down(&numspace_mutex);
+	if (s->num_free < 1)
+		rval = expand_numspace(s);
+	if (!rval) {
+		rval = find_first_zero_bit(s->bits, s->length << 3);
+		--s->num_free;
+		__set_bit(rval, s->bits);
+	}
+	up(&numspace_mutex);
+
+	return rval;
+}
+
+static void dealloc_unique_number(struct unique_numspace *s, int number)
+{
+	int old_val;
+
+	if (number >= 0) {
+		down(&numspace_mutex);
+		old_val = __test_and_clear_bit(number, s->bits);
+		if (old_val)
+			++s->num_free;
+		up(&numspace_mutex);
+	}
+}
+
+static struct unique_numspace disc_numspace;
+static struct unique_numspace cdrom_numspace;
+
+void devfs_add_partitioned(struct gendisk *disk)
+{
+	char dirname[64], symlink[16];
+
+	if (disk->devfs_name[0] != '\0')
+		sprintf(disk->devfs_name, "%s/disc%d", disk->disk_name,
+				disk->first_minor >> disk->minor_shift);
+
+	devfs_mk_dir(disk->devfs_name);
+	devfs_mk_bdev(MKDEV(disk->major, disk->first_minor),
+			S_IFBLK|S_IRUSR|S_IWUSR,
+			"%s/disc", disk->devfs_name);
+
+	disk->number = alloc_unique_number(&disc_numspace);
+
+	sprintf(symlink, "discs/disc%d", disk->number);
+	sprintf(dirname, "../%s", disk->devfs_name);
+	devfs_mk_symlink(symlink, dirname);
+
+}
+
+void devfs_add_disk(struct gendisk *disk)
+{
+	devfs_mk_bdev(MKDEV(disk->major, disk->first_minor),
+			(disk->flags & GENHD_FL_CD) ?
+				S_IFBLK|S_IRUGO|S_IWUGO :
+				S_IFBLK|S_IRUSR|S_IWUSR,
+			"%s", disk->devfs_name);
+
+	if (disk->flags & GENHD_FL_CD) {
+		char dirname[64], symlink[16];
+
+		disk->number = alloc_unique_number(&cdrom_numspace);
+
+		sprintf(symlink, "cdroms/cdrom%d", disk->number);
+		sprintf(dirname, "../%s", disk->devfs_name);
+		devfs_mk_symlink(symlink, dirname);
+	}
+}
+
+void devfs_remove_disk(struct gendisk *disk)
+{
+	if (disk->minors != 1) {
+		devfs_remove("discs/disc%d", disk->number);
+		dealloc_unique_number(&disc_numspace, disk->number);
+		devfs_remove("%s/disc", disk->devfs_name);
+	}
+	if (disk->flags & GENHD_FL_CD) {
+		devfs_remove("cdroms/cdrom%d", disk->number);
+		dealloc_unique_number(&cdrom_numspace, disk->number);
+	}
+	devfs_remove(disk->devfs_name);
+}
+
+

fs/partitions/devfs.h

+
+#ifdef CONFIG_DEVFS_FS
+void devfs_add_disk(struct gendisk *dev);
+void devfs_add_partitioned(struct gendisk *dev);
+void devfs_remove_disk(struct gendisk *dev);
+#else
+# define devfs_add_disk(disk)			do { } while (0)
+# define devfs_add_partitioned(disk)		do { } while (0)
+# define devfs_remove_disk(disk)		do { } while (0)
+#endif

include/linux/devfs_fs_kernel.h

@@ -34,10 +34,6 @@ extern void devfs_remove(const char *fmt, ...)
 	__attribute__((format (printf, 1, 2)));
 extern int devfs_register_tape(const char *name);
 extern void devfs_unregister_tape(int num);
-extern void devfs_create_partitions(struct gendisk *dev);
-extern void devfs_create_cdrom(struct gendisk *dev);
-extern void devfs_remove_partitions(struct gendisk *dev);
-extern void devfs_remove_cdrom(struct gendisk *dev);
 extern void devfs_register_partition(struct gendisk *dev, int part);
 extern void mount_devfs_fs(void);
 #else  /*  CONFIG_DEVFS_FS  */
@@ -73,18 +69,6 @@ static inline int devfs_register_tape (devfs_handle_t de)
 static inline void devfs_unregister_tape(int num)
 {
 }
-static inline void devfs_create_partitions(struct gendisk *dev)
-{
-}
-static inline void devfs_create_cdrom(struct gendisk *dev)
-{
-}
-static inline void devfs_remove_partitions(struct gendisk *dev)
-{
-}
-static inline void devfs_remove_cdrom(struct gendisk *dev)
-{
-}
 static inline void devfs_register_partition(struct gendisk *dev, int part)
 {
 }