Mike, I have a question for you below. > -----Original Message----- > From: Mike Snitzer [mailto:snitzer@xxxxxxxxxx] > Sent: Tuesday, May 08, 2012 4:56 PM > To: dm-devel@xxxxxxxxxx > Cc: agk@xxxxxxxxxx; hare@xxxxxxx; Moger, Babu; sekharan@xxxxxxxxxx; > Mike Snitzer > Subject: [PATCH v2 2/5] scsi_dh: add scsi_dh_attached_handler_name > > Introduce scsi_dh_attached_handler_name() to retrieve the name of the > scsi_dh that is attached to the scsi_device associated with the provided > request queue. Returns NULL if a scsi_dh is not attached. > > Also, fix scsi_dh_{attach,detach} function header comments to document > @q rather than @sdev. > > Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx> > --- > drivers/scsi/device_handler/scsi_dh.c | 31 > +++++++++++++++++++++++++++++-- > include/scsi/scsi_dh.h | 5 +++++ > 2 files changed, 34 insertions(+), 2 deletions(-) > > diff --git a/drivers/scsi/device_handler/scsi_dh.c > b/drivers/scsi/device_handler/scsi_dh.c > index 48e46f5..7497c78 100644 > --- a/drivers/scsi/device_handler/scsi_dh.c > +++ b/drivers/scsi/device_handler/scsi_dh.c > @@ -468,7 +468,8 @@ EXPORT_SYMBOL_GPL(scsi_dh_handler_exist); > > /* > * scsi_dh_attach - Attach device handler > - * @sdev - sdev the handler should be attached to > + * @q - Request queue that is associated with the scsi_device > + * the handler should be attached to > * @name - name of the handler to attach > */ > int scsi_dh_attach(struct request_queue *q, const char *name) > @@ -498,7 +499,8 @@ EXPORT_SYMBOL_GPL(scsi_dh_attach); > > /* > * scsi_dh_detach - Detach device handler > - * @sdev - sdev the handler should be detached from > + * @q - Request queue that is associated with the scsi_device > + * the handler should be detached from > * > * This function will detach the device handler only > * if the sdev is not part of the internal list, ie > @@ -527,6 +529,31 @@ void scsi_dh_detach(struct request_queue *q) > } > EXPORT_SYMBOL_GPL(scsi_dh_detach); > > +/* > + * scsi_dh_attached_handler_name - Get attached device handler's name > + * @q - Request queue that is associated with the scsi_device > + * that may have a device handler attached > + * > + * Returns name of attached scsi_dh, NULL if no handler is attached. > + */ > +const char *scsi_dh_attached_handler_name(struct request_queue *q) > +{ > + unsigned long flags; > + struct scsi_device *sdev; > + > + spin_lock_irqsave(q->queue_lock, flags); > + sdev = q->queuedata; > + if (!sdev || !get_device(&sdev->sdev_gendev)) > + sdev = NULL; > + spin_unlock_irqrestore(q->queue_lock, flags); > + > + if (!sdev || !sdev->scsi_dh_data) > + return NULL; > + > + return sdev->scsi_dh_data->scsi_dh->name; > +} I only see get_device call. I don't see matching put_device call. Was that on purspose? > +EXPORT_SYMBOL_GPL(scsi_dh_attached_handler_name); > + > static struct notifier_block scsi_dh_nb = { > .notifier_call = scsi_dh_notifier > }; > diff --git a/include/scsi/scsi_dh.h b/include/scsi/scsi_dh.h > index e3f2db2..94f502b 100644 > --- a/include/scsi/scsi_dh.h > +++ b/include/scsi/scsi_dh.h > @@ -60,6 +60,7 @@ extern int scsi_dh_activate(struct request_queue *, > activate_complete, void *); > extern int scsi_dh_handler_exist(const char *); > extern int scsi_dh_attach(struct request_queue *, const char *); > extern void scsi_dh_detach(struct request_queue *); > +extern const char *scsi_dh_attached_handler_name(struct request_queue > *q); > extern int scsi_dh_set_params(struct request_queue *, const char *); > #else > static inline int scsi_dh_activate(struct request_queue *req, > @@ -80,6 +81,10 @@ static inline void scsi_dh_detach(struct request_queue > *q) > { > return; > } > +static inline const char *scsi_dh_attached_handler_name(struct > request_queue *q) > +{ > + return NULL; > +} > static inline int scsi_dh_set_params(struct request_queue *req, const char > *params) > { > return -SCSI_DH_NOSYS; > -- > 1.7.4.4 -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
