Commit aebbb583 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
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sg: do not allocate a gendisk 



sg 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: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarLuis Chamberlain <mcgrof@kernel.org>
Link: https://lore.kernel.org/r/20210816131910.615153-4-hch@lst.de


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 45938335

drivers/scsi/sg.c

+9 −23
Original line number Diff line number Diff line
@@ -166,7 +166,7 @@ typedef struct sg_device { /* holds the state of each scsi generic device */ 
	bool exclude;		/* 1->open(O_EXCL) succeeded and is active */

	int open_cnt;		/* count of opens (perhaps < num(sfds) ) */

	char sgdebug;		/* 0->off, 1->sense, 9->dump dev, 10-> all devs */

	struct gendisk *disk;

	char name[DISK_NAME_LEN];

	struct cdev * cdev;	/* char_dev [sysfs: /sys/cdev/major/sg<n>] */

	struct kref d_ref;

} Sg_device;
@@ -202,8 +202,7 @@ static void sg_device_destroy(struct kref *kref); 
#define SZ_SG_REQ_INFO sizeof(sg_req_info_t)



#define sg_printk(prefix, sdp, fmt, a...) \

	sdev_prefix_printk(prefix, (sdp)->device,		\

			   (sdp)->disk->disk_name, fmt, ##a)

	sdev_prefix_printk(prefix, (sdp)->device, (sdp)->name, fmt, ##a)



/*

 * The SCSI interfaces that use read() and write() as an asynchronous variant of
@@ -832,7 +831,7 @@ sg_common_write(Sg_fd * sfp, Sg_request * srp, 


	srp->rq->timeout = timeout;

	kref_get(&sfp->f_ref); /* sg_rq_end_io() does kref_put(). */

	blk_execute_rq_nowait(sdp->disk, srp->rq, at_head, sg_rq_end_io);

	blk_execute_rq_nowait(NULL, srp->rq, at_head, sg_rq_end_io);

	return 0;

}
@@ -1119,8 +1118,7 @@ sg_ioctl_common(struct file *filp, Sg_device *sdp, Sg_fd *sfp, 
		return put_user(max_sectors_bytes(sdp->device->request_queue),

				ip);

	case BLKTRACESETUP:

		return blk_trace_setup(sdp->device->request_queue,

				       sdp->disk->disk_name,

		return blk_trace_setup(sdp->device->request_queue, NULL,

				       MKDEV(SCSI_GENERIC_MAJOR, sdp->index),

				       NULL, p);

	case BLKTRACESTART:
@@ -1456,7 +1454,7 @@ static struct class *sg_sysfs_class; 
static int sg_sysfs_valid = 0;



static Sg_device *

sg_alloc(struct gendisk *disk, struct scsi_device *scsidp)

sg_alloc(struct scsi_device *scsidp)

{

	struct request_queue *q = scsidp->request_queue;

	Sg_device *sdp;
@@ -1492,9 +1490,7 @@ sg_alloc(struct gendisk *disk, struct scsi_device *scsidp) 


	SCSI_LOG_TIMEOUT(3, sdev_printk(KERN_INFO, scsidp,

					"sg_alloc: dev=%d \n", k));

	sprintf(disk->disk_name, "sg%d", k);

	disk->first_minor = k;

	sdp->disk = disk;

	sprintf(sdp->name, "sg%d", k);

	sdp->device = scsidp;

	mutex_init(&sdp->open_rel_lock);

	INIT_LIST_HEAD(&sdp->sfds);
@@ -1521,19 +1517,11 @@ static int 
sg_add_device(struct device *cl_dev, struct class_interface *cl_intf)

{

	struct scsi_device *scsidp = to_scsi_device(cl_dev->parent);

	struct gendisk *disk;

	Sg_device *sdp = NULL;

	struct cdev * cdev = NULL;

	int error;

	unsigned long iflags;



	disk = alloc_disk(1);

	if (!disk) {

		pr_warn("%s: alloc_disk failed\n", __func__);

		return -ENOMEM;

	}

	disk->major = SCSI_GENERIC_MAJOR;



	error = -ENOMEM;

	cdev = cdev_alloc();

	if (!cdev) {
@@ -1543,7 +1531,7 @@ sg_add_device(struct device *cl_dev, struct class_interface *cl_intf) 
	cdev->owner = THIS_MODULE;

	cdev->ops = &sg_fops;



	sdp = sg_alloc(disk, scsidp);

	sdp = sg_alloc(scsidp);

	if (IS_ERR(sdp)) {

		pr_warn("%s: sg_alloc failed\n", __func__);

		error = PTR_ERR(sdp);
@@ -1561,7 +1549,7 @@ sg_add_device(struct device *cl_dev, struct class_interface *cl_intf) 
		sg_class_member = device_create(sg_sysfs_class, cl_dev->parent,

						MKDEV(SCSI_GENERIC_MAJOR,

						      sdp->index),

						sdp, "%s", disk->disk_name);

						sdp, "%s", sdp->name);

		if (IS_ERR(sg_class_member)) {

			pr_err("%s: device_create failed\n", __func__);

			error = PTR_ERR(sg_class_member);
@@ -1589,7 +1577,6 @@ sg_add_device(struct device *cl_dev, struct class_interface *cl_intf) 
	kfree(sdp);



out:

	put_disk(disk);

	if (cdev)

		cdev_del(cdev);

	return error;
@@ -1613,7 +1600,6 @@ sg_device_destroy(struct kref *kref) 
	SCSI_LOG_TIMEOUT(3,

		sg_printk(KERN_INFO, sdp, "sg_device_destroy\n"));



	put_disk(sdp->disk);

	kfree(sdp);

}
@@ -2606,7 +2592,7 @@ static int sg_proc_seq_show_debug(struct seq_file *s, void *v) 
		goto skip;

	read_lock(&sdp->sfd_lock);

	if (!list_empty(&sdp->sfds)) {

		seq_printf(s, " >>> device=%s ", sdp->disk->disk_name);

		seq_printf(s, " >>> device=%s ", sdp->name);

		if (atomic_read(&sdp->detaching))

			seq_puts(s, "detaching pending close ");

		else if (sdp->device) {