Simplify the refcounting and remove the need to clear disk->private_data
by implementing the ->free_disk method.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Bart Van Assche <bvanassche@xxxxxxx>
Reviewed-by: Ming Lei <ming.lei@xxxxxxxxxx>
Reviewed-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
---
drivers/scsi/sr.c | 124 ++++++++++------------------------------------
drivers/scsi/sr.h | 4 --
2 files changed, 26 insertions(+), 102 deletions(-)
diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c
index 569bda76a5175..11fbdc75bb711 100644
--- a/drivers/scsi/sr.c
+++ b/drivers/scsi/sr.c
@@ -109,11 +109,6 @@ static DEFINE_SPINLOCK(sr_index_lock);
static struct lock_class_key sr_bio_compl_lkclass;
-/* This semaphore is used to mediate the 0->1 reference get in the
- * face of object destruction (i.e. we can't allow a get on an
- * object after last put) */
-static DEFINE_MUTEX(sr_ref_mutex);
-
static int sr_open(struct cdrom_device_info *, int);
static void sr_release(struct cdrom_device_info *);
@@ -143,8 +138,6 @@ static const struct cdrom_device_ops sr_dops = {
.capability = SR_CAPABILITIES,
};
-static void sr_kref_release(struct kref *kref);
-
static inline struct scsi_cd *scsi_cd(struct gendisk *disk)
{
return disk->private_data;
@@ -163,38 +156,6 @@ static int sr_runtime_suspend(struct device *dev)
return 0;
}
-/*
- * The get and put routines for the struct scsi_cd. Note this entity
- * has a scsi_device pointer and owns a reference to this.
- */
-static inline struct scsi_cd *scsi_cd_get(struct gendisk *disk)
-{
- struct scsi_cd *cd = NULL;
-
- mutex_lock(&sr_ref_mutex);
- if (disk->private_data == NULL)
- goto out;
- cd = scsi_cd(disk);
- kref_get(&cd->kref);
- if (scsi_device_get(cd->device)) {
- kref_put(&cd->kref, sr_kref_release);
- cd = NULL;
- }
- out:
- mutex_unlock(&sr_ref_mutex);
- return cd;
-}
-
-static void scsi_cd_put(struct scsi_cd *cd)
-{
- struct scsi_device *sdev = cd->device;
-
- mutex_lock(&sr_ref_mutex);
- kref_put(&cd->kref, sr_kref_release);
- scsi_device_put(sdev);
- mutex_unlock(&sr_ref_mutex);
-}
-
static unsigned int sr_get_events(struct scsi_device *sdev)
{
u8 buf[8];
@@ -522,15 +483,13 @@ static void sr_revalidate_disk(struct scsi_cd *cd)
static int sr_block_open(struct block_device *bdev, fmode_t mode)
{
- struct scsi_cd *cd;
- struct scsi_device *sdev;
+ struct scsi_cd *cd = cd = scsi_cd(bdev->bd_disk);
+ struct scsi_device *sdev = cd->device;
int ret = -ENXIO;
- cd = scsi_cd_get(bdev->bd_disk);
- if (!cd)
- goto out;
+ if (scsi_device_get(cd->device))
+ return -ENXIO;
- sdev = cd->device;
scsi_autopm_get_device(sdev);
if (bdev_check_media_change(bdev))
sr_revalidate_disk(cd);
@@ -541,9 +500,7 @@ static int sr_block_open(struct block_device *bdev, fmode_t mode)
scsi_autopm_put_device(sdev);
if (ret)
- scsi_cd_put(cd);
-
-out:
+ scsi_device_put(cd->device);
return ret;
}
@@ -555,7 +512,7 @@ static void sr_block_release(struct gendisk *disk, fmode_t mode)
cdrom_release(&cd->cdi, mode);
mutex_unlock(&cd->lock);
- scsi_cd_put(cd);
+ scsi_device_put(cd->device);
}
static int sr_block_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
@@ -595,18 +552,24 @@ static int sr_block_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
static unsigned int sr_block_check_events(struct gendisk *disk,
unsigned int clearing)
{
- unsigned int ret = 0;
- struct scsi_cd *cd;
+ struct scsi_cd *cd = disk->private_data;
- cd = scsi_cd_get(disk);
- if (!cd)
+ if (atomic_read(&cd->device->disk_events_disable_depth))
return 0;
+ return cdrom_check_events(&cd->cdi, clearing);
+}
- if (!atomic_read(&cd->device->disk_events_disable_depth))
- ret = cdrom_check_events(&cd->cdi, clearing);
+static void sr_free_disk(struct gendisk *disk)
+{
+ struct scsi_cd *cd = disk->private_data;
- scsi_cd_put(cd);
- return ret;
+ spin_lock(&sr_index_lock);
+ clear_bit(MINOR(disk_devt(disk)), sr_index_bits);
+ spin_unlock(&sr_index_lock);
+
+ unregister_cdrom(&cd->cdi);
+ mutex_destroy(&cd->lock);
+ kfree(cd);
}
static const struct block_device_operations sr_bdops =
@@ -617,6 +580,7 @@ static const struct block_device_operations sr_bdops =
.ioctl = sr_block_ioctl,
.compat_ioctl = blkdev_compat_ptr_ioctl,
.check_events = sr_block_check_events,
+ .free_disk = sr_free_disk,
};
static int sr_open(struct cdrom_device_info *cdi, int purpose)
@@ -660,8 +624,6 @@ static int sr_probe(struct device *dev)
if (!cd)
goto fail;
- kref_init(&cd->kref);
-
disk = __alloc_disk_node(sdev->request_queue, NUMA_NO_NODE,
&sr_bio_compl_lkclass);
if (!disk)
@@ -727,10 +689,8 @@ static int sr_probe(struct device *dev)
sr_revalidate_disk(cd);
error = device_add_disk(&sdev->sdev_gendev, disk, NULL);
- if (error) {
- kref_put(&cd->kref, sr_kref_release);
- goto fail;
- }
+ if (error)
+ goto unregister_cdrom;
sdev_printk(KERN_DEBUG, sdev,
"Attached scsi CD-ROM %s\n", cd->cdi.name);
@@ -738,6 +698,8 @@ static int sr_probe(struct device *dev)
return 0;
+unregister_cdrom:
+ unregister_cdrom(&cd->cdi);
fail_minor:
spin_lock(&sr_index_lock);
clear_bit(minor, sr_index_bits);
@@ -1009,36 +971,6 @@ static int sr_read_cdda_bpc(struct cdrom_device_info *cdi, void __user *ubuf,
return ret;
}
-
-/**
- * sr_kref_release - Called to free the scsi_cd structure
- * @kref: pointer to embedded kref
- *
- * sr_ref_mutex must be held entering this routine. Because it is
- * called on last put, you should always use the scsi_cd_get()
- * scsi_cd_put() helpers which manipulate the semaphore directly
- * and never do a direct kref_put().
- **/
-static void sr_kref_release(struct kref *kref)
-{
- struct scsi_cd *cd = container_of(kref, struct scsi_cd, kref);
- struct gendisk *disk = cd->disk;
-
- spin_lock(&sr_index_lock);
- clear_bit(MINOR(disk_devt(disk)), sr_index_bits);
- spin_unlock(&sr_index_lock);
-
- unregister_cdrom(&cd->cdi);
-
- disk->private_data = NULL;
-
- put_disk(disk);
-
- mutex_destroy(&cd->lock);
-
- kfree(cd);
-}
-
static int sr_remove(struct device *dev)
{
struct scsi_cd *cd = dev_get_drvdata(dev);
@@ -1046,11 +978,7 @@ static int sr_remove(struct device *dev)
scsi_autopm_get_device(cd->device);
del_gendisk(cd->disk);
- dev_set_drvdata(dev, NULL);
-
- mutex_lock(&sr_ref_mutex);
- kref_put(&cd->kref, sr_kref_release);
- mutex_unlock(&sr_ref_mutex);
+ put_disk(cd->disk);
return 0;
}
diff --git a/drivers/scsi/sr.h b/drivers/scsi/sr.h
index d80af3fcb6f97..1175f2e213b56 100644
--- a/drivers/scsi/sr.h
+++ b/drivers/scsi/sr.h
@@ -18,7 +18,6 @@
#ifndef _SR_H
#define _SR_H
-#include <linux/kref.h>
#include <linux/mutex.h>
#define MAX_RETRIES 3
@@ -51,9 +50,6 @@ typedef struct scsi_cd {
struct cdrom_device_info cdi;
struct mutex lock;
- /* We hold gendisk and scsi_device references on probe and use
- * the refs on this kref to decide when to release them */
- struct kref kref;
struct gendisk *disk;
} Scsi_CD;
--
2.30.2
