[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>

1 files changed, 7 insertions, 1 deletions

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