From 7e8a74b177f17d100916b6ad415450f7c9508691 Mon Sep 17 00:00:00 2001 From: Mike Snitzer Date: Tue, 26 Jun 2012 14:32:03 -0400 Subject: [PATCH] [SCSI] 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 Tested-by: Babu Moger Reviewed-by: Chandra Seetharaman Acked-by: Hannes Reinecke Signed-off-by: James Bottomley --- drivers/scsi/device_handler/scsi_dh.c | 38 +++++++++++++++++++++++++-- include/scsi/scsi_dh.h | 6 +++++ 2 files changed, 42 insertions(+), 2 deletions(-) diff --git a/drivers/scsi/device_handler/scsi_dh.c b/drivers/scsi/device_handler/scsi_dh.c index 48e46f5b77cc..33e422e75835 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 +529,38 @@ 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 + * @gfp - the GFP mask used in the kmalloc() call when allocating memory + * + * Returns name of attached handler, NULL if no handler is attached. + * Caller must take care to free the returned string. + */ +const char *scsi_dh_attached_handler_name(struct request_queue *q, gfp_t gfp) +{ + unsigned long flags; + struct scsi_device *sdev; + const char *handler_name = NULL; + + 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) + return NULL; + + if (sdev->scsi_dh_data) + handler_name = kstrdup(sdev->scsi_dh_data->scsi_dh->name, gfp); + + put_device(&sdev->sdev_gendev); + return handler_name; +} +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 e3f2db212ddc..620c723ee8ed 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 *, gfp_t); extern int scsi_dh_set_params(struct request_queue *, const char *); #else static inline int scsi_dh_activate(struct request_queue *req, @@ -80,6 +81,11 @@ static inline void scsi_dh_detach(struct request_queue *q) { return; } +static inline const char *scsi_dh_attached_handler_name(struct request_queue *q, + gfp_t gfp) +{ + return NULL; +} static inline int scsi_dh_set_params(struct request_queue *req, const char *params) { return -SCSI_DH_NOSYS;