From: Song Liu [mailto:songliubraving@xxxxxx] Sent: Monday, August 25, 2014 10:26 AM To: Song Liu Cc: Dan Williams; Hannes Reinecke Subject: [PATCH 1/5] SES: close potential registration race From: Dan Williams <dan.j.williams@xxxxxxxxx> 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: Dan Williams <dan.j.williams@xxxxxxxxx> Signed-off-by: Song Liu <songliubraving@xxxxxx> Reviewed-by: Jens Axboe <axboe@xxxxxx> Cc: Hannes Reinecke <hare@xxxxxxx> --- drivers/misc/enclosure.c | 36 +++++++++++++++++++++++++----------- drivers/scsi/ses.c | 18 +++++++++++------- include/linux/enclosure.h | 5 +++-- 3 files changed, 39 insertions(+), 20 deletions(-) diff --git a/drivers/misc/enclosure.c b/drivers/misc/enclosure.c index 2cf2bbc..15faf61 100644 --- a/drivers/misc/enclosure.c +++ b/drivers/misc/enclosure.c @@ -249,27 +249,25 @@ static void enclosure_component_release(struct device *dev) 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, - unsigned int number, - enum enclosure_component_type type, - const char *name) +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; if (number >= edev->components) return ERR_PTR(-EINVAL); @@ -291,14 +289,30 @@ 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); diff --git a/drivers/scsi/ses.c b/drivers/scsi/ses.c index 80bfece..c2e8a98 100644 --- a/drivers/scsi/ses.c +++ b/drivers/scsi/ses.c @@ -423,16 +423,20 @@ static void ses_enclosure_data_process(struct enclosure_device *edev, type_ptr[0] == ENCLOSURE_COMPONENT_ARRAY_DEVICE) { if (create) - ecomp = enclosure_component_register(edev, - components++, - type_ptr[0], - name); + 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, - addl_desc_ptr); + 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; diff --git a/include/linux/enclosure.h b/include/linux/enclosure.h index 9a33c5f..a835d33 100644 --- a/include/linux/enclosure.h +++ b/include/linux/enclosure.h @@ -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, - enum enclosure_component_type, const char *); +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 *); -- 1.8.1 -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
