[SCSI] modify change_queue_depth to take in reason why it is being called

This patch modifies scsi_host_template->change_queue_depth so that
it takes an argument indicating why it is being called. This will be
used so that if a LLD needs to do some extra processing when
handling queue fulls or later ramp ups, it can do so.

This is a simple port of the drivers setting a change_queue_depth
callback. In the patch I just have these LLDs adjust the queue depth
if the user was requesting it.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>

[Vasu.Dev: v2
	Also converted pmcraid_change_queue_depth and then verified
all modules compile  using "make allmodconfig" for any new build
warnings on X86_64.

	Updated original description after combing two original
patches from Mike to make this patch git bisectable.]
Signed-off-by: Vasu Dev <vasu.dev@intel.com>
[jejb: fixed up 53c700]
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

4 files changed, 12 insertions, 4 deletions

diff --git a/include/scsi/libfc.h b/include/scsi/libfc.h
index 1662d73d85a7..9617f9365e45 100644
--- a/include/scsi/libfc.h
+++ b/include/scsi/libfc.h
@@ -919,7 +919,7 @@ int fc_slave_alloc(struct scsi_device *sdev);
 /*
  * Adjust the queue depth.
  */
-int fc_change_queue_depth(struct scsi_device *sdev, int qdepth);
+int fc_change_queue_depth(struct scsi_device *sdev, int qdepth, int reason);
 
 /*
  * Change the tag type.
diff --git a/include/scsi/libiscsi.h b/include/scsi/libiscsi.h
index a72edd4eceec..2db2bc26b1e9 100644
--- a/include/scsi/libiscsi.h
+++ b/include/scsi/libiscsi.h
@@ -333,7 +333,8 @@ struct iscsi_host {
 /*
  * scsi host template
  */
-extern int iscsi_change_queue_depth(struct scsi_device *sdev, int depth);
+extern int iscsi_change_queue_depth(struct scsi_device *sdev, int depth,
+				    int reason);
 extern int iscsi_eh_abort(struct scsi_cmnd *sc);
 extern int iscsi_eh_target_reset(struct scsi_cmnd *sc);
 extern int iscsi_eh_device_reset(struct scsi_cmnd *sc);
diff --git a/include/scsi/libsas.h b/include/scsi/libsas.h
index e78d3b62d8ec..9eaa3f05f954 100644
--- a/include/scsi/libsas.h
+++ b/include/scsi/libsas.h
@@ -634,7 +634,8 @@ extern int sas_target_alloc(struct scsi_target *);
 extern int sas_slave_alloc(struct scsi_device *);
 extern int sas_slave_configure(struct scsi_device *);
 extern void sas_slave_destroy(struct scsi_device *);
-extern int sas_change_queue_depth(struct scsi_device *, int new_depth);
+extern int sas_change_queue_depth(struct scsi_device *, int new_depth,
+				  int reason);
 extern int sas_change_queue_type(struct scsi_device *, int qt);
 extern int sas_bios_param(struct scsi_device *,
 			  struct block_device *,
diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index 6e728b176904..603054d8f40c 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -43,6 +43,12 @@ struct blk_queue_tags;
 #define DISABLE_CLUSTERING 0
 #define ENABLE_CLUSTERING 1
 
+enum {
+	SCSI_QDEPTH_DEFAULT,	/* default requested change, e.g. from sysfs */
+	SCSI_QDEPTH_QFULL,	/* scsi-ml requested due to queue full */
+	SCSI_QDEPTH_RAMP_UP,	/* scsi-ml requested due to threshhold event */
+};
+
 struct scsi_host_template {
 	struct module *module;
 	const char *name;
@@ -294,7 +300,7 @@ struct scsi_host_template {
 	 *
 	 * Status: OPTIONAL
 	 */
-	int (* change_queue_depth)(struct scsi_device *, int);
+	int (* change_queue_depth)(struct scsi_device *, int, int);
 
 	/*
 	 * Fill in this function to allow the changing of tag types