[SCSI] vmw_pvscsi: Add support for I/O requests coalescing.

This change allows pvscsi driver to coalesce I/O requests
before issuing them. The number of I/O's coalesced can be
dynamically configured based on the workload.

Signed-off-by: Rishi Mehta <rmehta@vmware.com>
Signed-off-by: Arvind Kumar <arvindkumar@vmware.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

1 files changed, 14 insertions, 3 deletions

diff --git a/drivers/scsi/vmw_pvscsi.h b/drivers/scsi/vmw_pvscsi.h
index a6437758384f..15a9ac68a50b 100644
--- a/drivers/scsi/vmw_pvscsi.h
+++ b/drivers/scsi/vmw_pvscsi.h
@@ -26,7 +26,7 @@
 
 #include <linux/types.h>
 
-#define PVSCSI_DRIVER_VERSION_STRING   "1.0.3.0-k"
+#define PVSCSI_DRIVER_VERSION_STRING   "1.0.4.0-k"
 
 #define PVSCSI_MAX_NUM_SG_ENTRIES_PER_SEGMENT 128
 
@@ -117,8 +117,9 @@ enum PVSCSICommands {
         PVSCSI_CMD_CONFIG            = 7,
         PVSCSI_CMD_SETUP_MSG_RING    = 8,
         PVSCSI_CMD_DEVICE_UNPLUG     = 9,
+        PVSCSI_CMD_SETUP_REQCALLTHRESHOLD     = 10,
 
-        PVSCSI_CMD_LAST              = 10  /* has to be last */
+        PVSCSI_CMD_LAST              = 11  /* has to be last */
 };
 
 /*
@@ -141,6 +142,14 @@ struct PVSCSICmdDescConfigCmd {
         u32 _pad;
 } __packed;
 
+/*
+ * Command descriptor for PVSCSI_CMD_SETUP_REQCALLTHRESHOLD --
+ */
+
+struct PVSCSICmdDescSetupReqCall {
+        u32 enable;
+} __packed;
+
 enum PVSCSIConfigPageType {
         PVSCSI_CONFIG_PAGE_CONTROLLER = 0x1958,
         PVSCSI_CONFIG_PAGE_PHY        = 0x1959,
@@ -261,7 +270,9 @@ struct PVSCSIRingsState {
         u32     cmpConsIdx;
         u32     cmpNumEntriesLog2;
 
-        u8      _pad[104];
+        u32     reqCallThreshold;
+
+        u8      _pad[100];
 
         u32     msgProdIdx;
         u32     msgConsIdx;