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Commit ed09dcc8 authored by Dan Williams's avatar Dan Williams Committed by Christoph Hellwig
Browse files

ses: close potential registration race 



The slot and address fields have a small window of instability when
userspace can read them before initialization. Separate
enclosure_component
allocation from registration.

Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
Signed-off-by: default avatarSong Liu <songliubraving@fb.com>
Reviewed-by: default avatarJens Axboe <axboe@fb.com>
Cc: Hannes Reinecke <hare@suse.de>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
parent acd6d738

drivers/misc/enclosure.c

+26 −11
Original line number Diff line number Diff line
@@ -273,27 +273,26 @@ enclosure_component_find_by_name(struct enclosure_device *edev, 
static const struct attribute_group *enclosure_component_groups[];



/**

 * enclosure_component_register - add a particular component to an enclosure

 * enclosure_component_alloc - prepare a new enclosure component

 * @edev:	the enclosure to add the component

 * @num:	the device number

 * @type:	the type of component being added

 * @name:	an optional name to appear in sysfs (leave NULL if none)

 *

 * Registers the component.  The name is optional for enclosures that

 * give their components a unique name.  If not, leave the field NULL

 * and a name will be assigned.

 * The name is optional for enclosures that give their components a unique

 * name.  If not, leave the field NULL and a name will be assigned.

 *

 * Returns a pointer to the enclosure component or an error.

 */

struct enclosure_component *

enclosure_component_register(struct enclosure_device *edev,

enclosure_component_alloc(struct enclosure_device *edev,

			  unsigned int number,

			  enum enclosure_component_type type,

			  const char *name)

{

	struct enclosure_component *ecomp;

	struct device *cdev;

	int err, i;

	int i;

	char newname[COMPONENT_NAME_SIZE];



	if (number >= edev->components)
@@ -327,14 +326,30 @@ enclosure_component_register(struct enclosure_device *edev, 
	cdev->release = enclosure_component_release;

	cdev->groups = enclosure_component_groups;



	return ecomp;

}

EXPORT_SYMBOL_GPL(enclosure_component_alloc);



/**

 * enclosure_component_register - publishes an initialized enclosure component

 * @ecomp:	component to add

 *

 * Returns 0 on successful registration, releases the component otherwise

 */

int enclosure_component_register(struct enclosure_component *ecomp)

{

	struct device *cdev;

	int err;



	cdev = &ecomp->cdev;

	err = device_register(cdev);

	if (err) {

		ecomp->number = -1;

		put_device(cdev);

		return ERR_PTR(err);

		return err;

	}



	return ecomp;

	return 0;

}

EXPORT_SYMBOL_GPL(enclosure_component_register);

drivers/scsi/ses.c

+14 −7
Original line number Diff line number Diff line
@@ -423,16 +423,23 @@ static void ses_enclosure_data_process(struct enclosure_device *edev, 
			    type_ptr[0] == ENCLOSURE_COMPONENT_ARRAY_DEVICE) {



				if (create)

					ecomp =	enclosure_component_register(edev,

					ecomp =	enclosure_component_alloc(

						edev,

						components++,

						type_ptr[0],

						name);

				else

					ecomp = &edev->component[components++];



				if (!IS_ERR(ecomp) && addl_desc_ptr)

					ses_process_descriptor(ecomp,

				if (!IS_ERR(ecomp)) {

					if (addl_desc_ptr)

						ses_process_descriptor(

							ecomp,

							addl_desc_ptr);

					if (create)

						enclosure_component_register(

							ecomp);

				}

			}

			if (desc_ptr)

				desc_ptr += len;

include/linux/enclosure.h

+3 −2
Original line number Diff line number Diff line
@@ -120,8 +120,9 @@ enclosure_register(struct device *, const char *, int, 
		   struct enclosure_component_callbacks *);

void enclosure_unregister(struct enclosure_device *);

struct enclosure_component *

enclosure_component_register(struct enclosure_device *, unsigned int,

enclosure_component_alloc(struct enclosure_device *, unsigned int,

			  enum enclosure_component_type, const char *);

int enclosure_component_register(struct enclosure_component *);

int enclosure_add_device(struct enclosure_device *enclosure, int component,

			 struct device *dev);

int enclosure_remove_device(struct enclosure_device *, struct device *);