[PATCH 2/9] st: do not allocate a gendisk

Christoph Hellwig
2021-08-16T13:22:46Z

st is a character driver and thus does not need to allocate a gendisk,
which is only used for file system-like block layer I/O on block
devices.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
drivers/scsi/st.c | 49 ++++++++++++-----------------------------------
drivers/scsi/st.h | 2 +-
2 files changed, 13 insertions(+), 38 deletions(-)

diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c
index c6f14540ae03..d1abc020f3c0 100644
--- a/drivers/scsi/st.c
+++ b/drivers/scsi/st.c
@@ -309,13 +309,8 @@ static char * st_incompatible(struct scsi_device* SDp)
}
\f

-static inline char *tape_name(struct scsi_tape *tape)
-{
- return tape->disk->disk_name;
-}
-
#define st_printk(prefix, t, fmt, a...) \
- sdev_prefix_printk(prefix, (t)->device, tape_name(t), fmt, ##a)
+ sdev_prefix_printk(prefix, (t)->device, (t)->name, fmt, ##a)
#ifdef DEBUG
#define DEBC_printk(t, fmt, a...) \
if (debugging) { st_printk(ST_DEB_MSG, t, fmt, ##a ); }
@@ -363,7 +358,7 @@ static int st_chk_result(struct scsi_tape *STp, struct st_request * SRpnt)
int result = SRpnt->result;
u8 scode;
DEB(const char *stp;)
- char *name = tape_name(STp);
+ char *name = STp->name;
struct st_cmdstatus *cmdstatp;

if (!result)
@@ -3841,8 +3836,9 @@ static long st_ioctl_common(struct file *file, unsigned int cmd_in, void __user
!capable(CAP_SYS_RAWIO))
i = -EPERM;
else
- i = scsi_cmd_ioctl(STp->disk->queue, STp->disk,
- file->f_mode, cmd_in, p);
+ i = scsi_cmd_ioctl(STp->device->request_queue,
+ NULL, file->f_mode, cmd_in,
+ p);
if (i != -ENOTTY)
return i;
break;
@@ -4216,7 +4212,7 @@ static int create_one_cdev(struct scsi_tape *tape, int mode, int rew)

i = mode << (4 - ST_NBR_MODE_BITS);
snprintf(name, 10, "%s%s%s", rew ? "n" : "",
- tape->disk->disk_name, st_formats[i]);
+ tape->name, st_formats[i]);

dev = device_create(&st_sysfs_class, &tape->device->sdev_gendev,
cdev_devno, &tape->modes[mode], "%s", name);
@@ -4271,7 +4267,6 @@ static void remove_cdevs(struct scsi_tape *tape)
static int st_probe(struct device *dev)
{
struct scsi_device *SDp = to_scsi_device(dev);
- struct gendisk *disk = NULL;
struct scsi_tape *tpnt = NULL;
struct st_modedef *STm;
struct st_partstat *STps;
@@ -4301,27 +4296,13 @@ static int st_probe(struct device *dev)
goto out;
}

- disk = alloc_disk(1);
- if (!disk) {
- sdev_printk(KERN_ERR, SDp,
- "st: out of memory. Device not attached.\n");
- goto out_buffer_free;
- }
-
tpnt = kzalloc(sizeof(struct scsi_tape), GFP_KERNEL);
if (tpnt == NULL) {
sdev_printk(KERN_ERR, SDp,
"st: Can't allocate device descriptor.\n");
- goto out_put_disk;
+ goto out_buffer_free;
}
kref_init(&tpnt->kref);
- tpnt->disk = disk;
- disk->private_data = &tpnt->driver;
- /* SCSI tape doesn't register this gendisk via add_disk(). Manually
- * take queue reference that release_disk() expects. */
- if (!blk_get_queue(SDp->request_queue))
- goto out_put_disk;
- disk->queue = SDp->request_queue;
tpnt->driver = &st_template;

tpnt->device = SDp;
@@ -4394,10 +4375,10 @@ static int st_probe(struct device *dev)
idr_preload_end();
if (error < 0) {
pr_warn("st: idr allocation failed: %d\n", error);
- goto out_put_queue;
+ goto out_free_tape;
}
tpnt->index = error;
- sprintf(disk->disk_name, "st%d", tpnt->index);
+ sprintf(tpnt->name, "st%d", tpnt->index);
tpnt->stats = kzalloc(sizeof(struct scsi_tape_stats), GFP_KERNEL);
if (tpnt->stats == NULL) {
sdev_printk(KERN_ERR, SDp,
@@ -4414,9 +4395,9 @@ static int st_probe(struct device *dev)
scsi_autopm_put_device(SDp);

sdev_printk(KERN_NOTICE, SDp,
- "Attached scsi tape %s\n", tape_name(tpnt));
+ "Attached scsi tape %s\n", tpnt->name);
sdev_printk(KERN_INFO, SDp, "%s: try direct i/o: %s (alignment %d B)\n",
- tape_name(tpnt), tpnt->try_dio ? "yes" : "no",
+ tpnt->name, tpnt->try_dio ? "yes" : "no",
queue_dma_alignment(SDp->request_queue) + 1);

return 0;
@@ -4428,10 +4409,7 @@ static int st_probe(struct device *dev)
spin_lock(&st_index_lock);
idr_remove(&st_index_idr, tpnt->index);
spin_unlock(&st_index_lock);
-out_put_queue:
- blk_put_queue(disk->queue);
-out_put_disk:
- put_disk(disk);
+out_free_tape:
kfree(tpnt);
out_buffer_free:
kfree(buffer);
@@ -4470,7 +4448,6 @@ static int st_remove(struct device *dev)
static void scsi_tape_release(struct kref *kref)
{
struct scsi_tape *tpnt = to_scsi_tape(kref);
- struct gendisk *disk = tpnt->disk;

tpnt->device = NULL;

@@ -4480,8 +4457,6 @@ static void scsi_tape_release(struct kref *kref)
kfree(tpnt->buffer);
}

- disk->private_data = NULL;
- put_disk(disk);
kfree(tpnt->stats);
kfree(tpnt);
return;
diff --git a/drivers/scsi/st.h b/drivers/scsi/st.h
index 9d3c38bb0794..c0ef0d9aaf8a 100644
--- a/drivers/scsi/st.h
+++ b/drivers/scsi/st.h
@@ -187,7 +187,7 @@ struct scsi_tape {
unsigned char last_cmnd[6];
unsigned char last_sense[16];
#endif
- struct gendisk *disk;
+ char name[DISK_NAME_LEN];
struct kref kref;
struct scsi_tape_stats *stats;
};
--
2.30.2