[patch 6/8] ide-floppy: add basic refcounting

From: Bartlomiej Zolnierkiewicz
Date: Fri Jan 21 2005 - 18:45:03 EST


Similar changes as for ide-cd.c.

diff -Nru a/drivers/ide/ide-floppy.c b/drivers/ide/ide-floppy.c
--- a/drivers/ide/ide-floppy.c 2005-01-21 23:41:14 +01:00
+++ b/drivers/ide/ide-floppy.c 2005-01-21 23:41:14 +01:00
@@ -274,8 +274,9 @@
* driver due to an interrupt or a timer event is stored in a variable
* of type idefloppy_floppy_t, defined below.
*/
-typedef struct {
- ide_drive_t *drive;
+typedef struct ide_floppy_obj {
+ ide_drive_t *drive;
+ struct kref kref;

/* Current packet command */
idefloppy_pc_t *pc;
@@ -514,6 +515,33 @@
u8 reserved[4];
} idefloppy_mode_parameter_header_t;

+static DECLARE_MUTEX(idefloppy_ref_sem);
+
+#define to_ide_floppy(obj) container_of(obj, struct ide_floppy_obj, kref)
+
+#define ide_floppy_g(disk) ((disk)->private_data)
+
+static struct ide_floppy_obj *ide_floppy_get(struct gendisk *disk)
+{
+ struct ide_floppy_obj *floppy = NULL;
+
+ down(&idefloppy_ref_sem);
+ floppy = ide_floppy_g(disk);
+ if (floppy)
+ kref_get(&floppy->kref);
+ up(&idefloppy_ref_sem);
+ return floppy;
+}
+
+static void ide_floppy_release(struct kref *);
+
+static void ide_floppy_put(struct ide_floppy_obj *floppy)
+{
+ down(&idefloppy_ref_sem);
+ kref_put(&floppy->kref, ide_floppy_release);
+ up(&idefloppy_ref_sem);
+}
+
/*
* Too bad. The drive wants to send us data which we are not ready to accept.
* Just throw it away.
@@ -1792,9 +1820,6 @@
struct idefloppy_id_gcw gcw;

*((u16 *) &gcw) = drive->id->config;
- drive->driver_data = floppy;
- memset(floppy, 0, sizeof(idefloppy_floppy_t));
- floppy->drive = drive;
floppy->pc = floppy->pc_stack;
if (gcw.drq_type == 1)
set_bit(IDEFLOPPY_DRQ_INTERRUPT, &floppy->flags);
@@ -1838,13 +1863,26 @@

if (ide_unregister_subdriver(drive))
return 1;
- drive->driver_data = NULL;
- kfree(floppy);
+
del_gendisk(g);
- g->fops = ide_fops;
+
+ ide_floppy_put(floppy);
+
return 0;
}

+static void ide_floppy_release(struct kref *kref)
+{
+ struct ide_floppy_obj *floppy = to_ide_floppy(kref);
+ ide_drive_t *drive = floppy->drive;
+ struct gendisk *g = drive->disk;
+
+ drive->driver_data = NULL;
+ g->private_data = NULL;
+ g->fops = ide_fops;
+ kfree(floppy);
+}
+
#ifdef CONFIG_PROC_FS

static int proc_idefloppy_read_capacity
@@ -1893,14 +1931,21 @@

static int idefloppy_open(struct inode *inode, struct file *filp)
{
- ide_drive_t *drive = inode->i_bdev->bd_disk->private_data;
- idefloppy_floppy_t *floppy = drive->driver_data;
+ struct gendisk *disk = inode->i_bdev->bd_disk;
+ struct ide_floppy_obj *floppy;
+ ide_drive_t *drive;
idefloppy_pc_t pc;
+ int ret = 0;

- drive->usage++;
-
debug_log(KERN_INFO "Reached idefloppy_open\n");

+ if (!(floppy = ide_floppy_get(disk)))
+ return -ENXIO;
+
+ drive = floppy->drive;
+
+ drive->usage++;
+
if (drive->usage == 1) {
clear_bit(IDEFLOPPY_FORMAT_IN_PROGRESS, &floppy->flags);
/* Just in case */
@@ -1920,13 +1965,15 @@
*/
) {
drive->usage--;
- return -EIO;
+ ret = -EIO;
+ goto out_put_floppy;
}

if (floppy->wp && (filp->f_mode & 2)) {
drive->usage--;
- return -EROFS;
- }
+ ret = -EROFS;
+ goto out_put_floppy;
+ }
set_bit(IDEFLOPPY_MEDIA_CHANGED, &floppy->flags);
/* IOMEGA Clik! drives do not support lock/unlock commands */
if (!test_bit(IDEFLOPPY_CLIK_DRIVE, &floppy->flags)) {
@@ -1936,21 +1983,26 @@
check_disk_change(inode->i_bdev);
} else if (test_bit(IDEFLOPPY_FORMAT_IN_PROGRESS, &floppy->flags)) {
drive->usage--;
- return -EBUSY;
+ ret = -EBUSY;
+ goto out_put_floppy;
}
return 0;
+
+out_put_floppy:
+ ide_floppy_put(floppy);
+ return ret;
}

static int idefloppy_release(struct inode *inode, struct file *filp)
{
- ide_drive_t *drive = inode->i_bdev->bd_disk->private_data;
+ struct gendisk *disk = inode->i_bdev->bd_disk;
+ struct ide_floppy_obj *floppy = ide_floppy_g(disk);
+ ide_drive_t *drive = floppy->drive;
idefloppy_pc_t pc;

debug_log(KERN_INFO "Reached idefloppy_release\n");

if (drive->usage == 1) {
- idefloppy_floppy_t *floppy = drive->driver_data;
-
/* IOMEGA Clik! drives do not support lock/unlock commands */
if (!test_bit(IDEFLOPPY_CLIK_DRIVE, &floppy->flags)) {
idefloppy_create_prevent_cmd(&pc, 0);
@@ -1960,6 +2012,9 @@
clear_bit(IDEFLOPPY_FORMAT_IN_PROGRESS, &floppy->flags);
}
drive->usage--;
+
+ ide_floppy_put(floppy);
+
return 0;
}

@@ -1967,8 +2022,8 @@
unsigned int cmd, unsigned long arg)
{
struct block_device *bdev = inode->i_bdev;
- ide_drive_t *drive = bdev->bd_disk->private_data;
- idefloppy_floppy_t *floppy = drive->driver_data;
+ struct ide_floppy_obj *floppy = ide_floppy_g(bdev->bd_disk);
+ ide_drive_t *drive = floppy->drive;
void __user *argp = (void __user *)arg;
int err = generic_ide_ioctl(drive, file, bdev, cmd, arg);
int prevent = (arg) ? 1 : 0;
@@ -2031,8 +2086,8 @@

static int idefloppy_media_changed(struct gendisk *disk)
{
- ide_drive_t *drive = disk->private_data;
- idefloppy_floppy_t *floppy = drive->driver_data;
+ struct ide_floppy_obj *floppy = ide_floppy_g(disk);
+ ide_drive_t *drive = floppy->drive;

/* do not scan partitions twice if this is a removable device */
if (drive->attach) {
@@ -2044,8 +2099,8 @@

static int idefloppy_revalidate_disk(struct gendisk *disk)
{
- ide_drive_t *drive = disk->private_data;
- set_capacity(disk, idefloppy_capacity(drive));
+ struct ide_floppy_obj *floppy = ide_floppy_g(disk);
+ set_capacity(disk, idefloppy_capacity(floppy->drive));
return 0;
}

@@ -2085,6 +2140,15 @@
kfree (floppy);
goto failed;
}
+
+ memset(floppy, 0, sizeof(*floppy));
+
+ kref_init(&floppy->kref);
+
+ floppy->drive = drive;
+
+ drive->driver_data = floppy;
+
DRIVER(drive)->busy++;
idefloppy_setup (drive, floppy);
DRIVER(drive)->busy--;
@@ -2093,6 +2157,7 @@
strcpy(g->devfs_name, drive->devfs_name);
g->flags = drive->removable ? GENHD_FL_REMOVABLE : 0;
g->fops = &idefloppy_ops;
+ g->private_data = floppy;
drive->attach = 1;
add_disk(g);
return 0;
-
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