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Commit c7b364f7 authored by Takashi Iwai's avatar Takashi Iwai Committed by Greg Kroah-Hartman
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USB: gadget: f_mass_storage: use static attribute groups for sysfs entries 



Instead of manual device_create_file() and device_remove_file() calls,
assign the static attribute groups to the lun device to register.
The RO or RW permissions for some entries are decided in is_visible
callback.  This simplifies the code (also the logic) and avoids the
possible races, too.

Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent c60b89aa

drivers/usb/gadget/function/f_mass_storage.c

+33 −74
Original line number Diff line number Diff line
@@ -2624,13 +2624,10 @@ static ssize_t file_store(struct device *dev, struct device_attribute *attr, 
	return fsg_store_file(curlun, filesem, buf, count);

}



static DEVICE_ATTR_RW(ro);

static DEVICE_ATTR_RW(nofua);

static DEVICE_ATTR_RW(file);



static struct device_attribute dev_attr_ro_cdrom = __ATTR_RO(ro);

static struct device_attribute dev_attr_file_nonremovable = __ATTR_RO(file);



/* mode wil be set in fsg_lun_attr_is_visible() */

static DEVICE_ATTR(ro, 0, ro_show, ro_store);

static DEVICE_ATTR(file, 0, file_show, file_store);



/****************************** FSG COMMON ******************************/
@@ -2745,40 +2742,10 @@ int fsg_common_set_num_buffers(struct fsg_common *common, unsigned int n) 
}

EXPORT_SYMBOL_GPL(fsg_common_set_num_buffers);



static inline void fsg_common_remove_sysfs(struct fsg_lun *lun)

{

	device_remove_file(&lun->dev, &dev_attr_nofua);

	/*

	 * device_remove_file() =>

	 *

	 * here the attr (e.g. dev_attr_ro) is only used to be passed to:

	 *

	 *	sysfs_remove_file() =>

	 *

	 *	here e.g. both dev_attr_ro_cdrom and dev_attr_ro are in

	 *	the same namespace and

	 *	from here only attr->name is passed to:

	 *

	 *		sysfs_hash_and_remove()

	 *

	 *		attr->name is the same for dev_attr_ro_cdrom and

	 *		dev_attr_ro

	 *		attr->name is the same for dev_attr_file and

	 *		dev_attr_file_nonremovable

	 *

	 * so we don't differentiate between removing e.g. dev_attr_ro_cdrom

	 * and dev_attr_ro

	 */

	device_remove_file(&lun->dev, &dev_attr_ro);

	device_remove_file(&lun->dev, &dev_attr_file);

}



void fsg_common_remove_lun(struct fsg_lun *lun, bool sysfs)

{

	if (sysfs) {

		fsg_common_remove_sysfs(lun);

	if (sysfs)

		device_unregister(&lun->dev);

	}

	fsg_lun_close(lun);

	kfree(lun);

}
@@ -2877,41 +2844,35 @@ int fsg_common_set_cdev(struct fsg_common *common, 
}

EXPORT_SYMBOL_GPL(fsg_common_set_cdev);



static inline int fsg_common_add_sysfs(struct fsg_common *common,

				       struct fsg_lun *lun)

static struct attribute *fsg_lun_dev_attrs[] = {

	&dev_attr_ro.attr,

	&dev_attr_file.attr,

	&dev_attr_nofua.attr,

	NULL

};



static umode_t fsg_lun_dev_is_visible(struct kobject *kobj,

				      struct attribute *attr, int idx)

{

	int rc;

	struct device *dev = kobj_to_dev(kobj);

	struct fsg_lun *lun = fsg_lun_from_dev(dev);



	rc = device_register(&lun->dev);

	if (rc) {

		put_device(&lun->dev);

		return rc;

	if (attr == &dev_attr_ro.attr)

		return lun->cdrom ? S_IRUGO : (S_IWUSR | S_IRUGO);

	if (attr == &dev_attr_file.attr)

		return lun->removable ? (S_IWUSR | S_IRUGO) : S_IRUGO;

	return attr->mode;

}



	rc = device_create_file(&lun->dev,

				lun->cdrom

			      ? &dev_attr_ro_cdrom

			      : &dev_attr_ro);

	if (rc)

		goto error;

	rc = device_create_file(&lun->dev,

				lun->removable

			      ? &dev_attr_file

			      : &dev_attr_file_nonremovable);

	if (rc)

		goto error;

	rc = device_create_file(&lun->dev, &dev_attr_nofua);

	if (rc)

		goto error;



	return 0;

static const struct attribute_group fsg_lun_dev_group = {

	.attrs = fsg_lun_dev_attrs,

	.is_visible = fsg_lun_dev_is_visible,

};



error:

	/* removing nonexistent files is a no-op */

	fsg_common_remove_sysfs(lun);

	device_unregister(&lun->dev);

	return rc;

}

static const struct attribute_group *fsg_lun_dev_groups[] = {

	&fsg_lun_dev_group,

	NULL

};



int fsg_common_create_lun(struct fsg_common *common, struct fsg_lun_config *cfg,

			  unsigned int id, const char *name,
@@ -2949,13 +2910,15 @@ int fsg_common_create_lun(struct fsg_common *common, struct fsg_lun_config *cfg, 
	} else {

		lun->dev.release = fsg_lun_release;

		lun->dev.parent = &common->gadget->dev;

		lun->dev.groups = fsg_lun_dev_groups;

		dev_set_drvdata(&lun->dev, &common->filesem);

		dev_set_name(&lun->dev, "%s", name);

		lun->name = dev_name(&lun->dev);



		rc = fsg_common_add_sysfs(common, lun);

		rc = device_register(&lun->dev);

		if (rc) {

			pr_info("failed to register LUN%d: %d\n", id, rc);

			put_device(&lun->dev);

			goto error_sysfs;

		}

	}
@@ -2988,10 +2951,8 @@ int fsg_common_create_lun(struct fsg_common *common, struct fsg_lun_config *cfg, 
	return 0;



error_lun:

	if (common->sysfs) {

		fsg_common_remove_sysfs(lun);

	if (common->sysfs)

		device_unregister(&lun->dev);

	}

	fsg_lun_close(lun);

	common->luns[id] = NULL;

error_sysfs:
@@ -3077,8 +3038,6 @@ static void fsg_common_release(struct kref *ref) 
			struct fsg_lun *lun = *lun_it;

			if (!lun)

				continue;

			if (common->sysfs)

				fsg_common_remove_sysfs(lun);

			fsg_lun_close(lun);

			if (common->sysfs)

				device_unregister(&lun->dev);