aacraid: SCSI blk tag support

The method to allocate and free FIB's in the present code utilizes
spinlocks. Multiple IO's have to wait on the spinlock to acquire or free
fibs creating a performance bottleneck.

An alternative solution would be to use block layer tags to keep track
of the fibs allocated and freed. To this end aac_fib_alloc_tag was
created to utilize the blk layer tags to plug into the Fib pool.These
functions are used exclusively in the IO path. 8 fibs are reserved for
the use of AIF management software and utilize the previous spinlock
based implementations.
Signed-off-by: Raghava Aditya Renukunta <RaghavaAditya.Renukunta@pmcs.com>
Reviewed-by: Shane Seymour <shane.seymour@hpe.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Tomas Henzl <thenzl@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/aacraid/aachba.c

@@ -323,7 +323,6 @@ static inline int aac_valid_context(struct scsi_cmnd *scsicmd,
 	if (unlikely(!scsicmd || !scsicmd->scsi_done)) {
 		dprintk((KERN_WARNING "aac_valid_context: scsi command corrupt\n"));
 		aac_fib_complete(fibptr);
-		aac_fib_free(fibptr);
 		return 0;
 	}
 	scsicmd->SCp.phase = AAC_OWNER_MIDLEVEL;
@@ -331,7 +330,6 @@ static inline int aac_valid_context(struct scsi_cmnd *scsicmd,
 	if (unlikely(!device || !scsi_device_online(device))) {
 		dprintk((KERN_WARNING "aac_valid_context: scsi device corrupt\n"));
 		aac_fib_complete(fibptr);
-		aac_fib_free(fibptr);
 		return 0;
 	}
 	return 1;
@@ -541,7 +539,6 @@ static void get_container_name_callback(void *context, struct fib * fibptr)
 	scsicmd->result = DID_OK << 16 | COMMAND_COMPLETE << 8 | SAM_STAT_GOOD;
 
 	aac_fib_complete(fibptr);
-	aac_fib_free(fibptr);
 	scsicmd->scsi_done(scsicmd);
 }
 
@@ -557,7 +554,8 @@ static int aac_get_container_name(struct scsi_cmnd * scsicmd)
 
 	dev = (struct aac_dev *)scsicmd->device->host->hostdata;
 
-	if (!(cmd_fibcontext = aac_fib_alloc(dev)))
+	cmd_fibcontext = aac_fib_alloc_tag(dev, scsicmd);
+	if (!cmd_fibcontext)
 		return -ENOMEM;
 
 	aac_fib_init(cmd_fibcontext);
@@ -586,7 +584,6 @@ static int aac_get_container_name(struct scsi_cmnd * scsicmd)
 
 	printk(KERN_WARNING "aac_get_container_name: aac_fib_send failed with status: %d.\n", status);
 	aac_fib_complete(cmd_fibcontext);
-	aac_fib_free(cmd_fibcontext);
 	return -1;
 }
 
@@ -1024,7 +1021,6 @@ static void get_container_serial_callback(void *context, struct fib * fibptr)
 	scsicmd->result = DID_OK << 16 | COMMAND_COMPLETE << 8 | SAM_STAT_GOOD;
 
 	aac_fib_complete(fibptr);
-	aac_fib_free(fibptr);
 	scsicmd->scsi_done(scsicmd);
 }
 
@@ -1040,7 +1036,8 @@ static int aac_get_container_serial(struct scsi_cmnd * scsicmd)
 
 	dev = (struct aac_dev *)scsicmd->device->host->hostdata;
 
-	if (!(cmd_fibcontext = aac_fib_alloc(dev)))
+	cmd_fibcontext = aac_fib_alloc_tag(dev, scsicmd);
+	if (!cmd_fibcontext)
 		return -ENOMEM;
 
 	aac_fib_init(cmd_fibcontext);
@@ -1068,7 +1065,6 @@ static int aac_get_container_serial(struct scsi_cmnd * scsicmd)
 
 	printk(KERN_WARNING "aac_get_container_serial: aac_fib_send failed with status: %d.\n", status);
 	aac_fib_complete(cmd_fibcontext);
-	aac_fib_free(cmd_fibcontext);
 	return -1;
 }
 
@@ -1869,7 +1865,6 @@ static void io_callback(void *context, struct fib * fibptr)
 		break;
 	}
 	aac_fib_complete(fibptr);
-	aac_fib_free(fibptr);
 
 	scsicmd->scsi_done(scsicmd);
 }
@@ -1954,7 +1949,8 @@ static int aac_read(struct scsi_cmnd * scsicmd)
 	/*
 	 *	Alocate and initialize a Fib
 	 */
-	if (!(cmd_fibcontext = aac_fib_alloc(dev))) {
+	cmd_fibcontext = aac_fib_alloc_tag(dev, scsicmd);
+	if (!cmd_fibcontext) {
 		printk(KERN_WARNING "aac_read: fib allocation failed\n");
 		return -1;
 	}
@@ -2051,7 +2047,8 @@ static int aac_write(struct scsi_cmnd * scsicmd)
 	/*
 	 *	Allocate and initialize a Fib then setup a BlockWrite command
 	 */
-	if (!(cmd_fibcontext = aac_fib_alloc(dev))) {
+	cmd_fibcontext = aac_fib_alloc_tag(dev, scsicmd);
+	if (!cmd_fibcontext) {
 		/* FIB temporarily unavailable,not catastrophic failure */
 
 		/* scsicmd->result = DID_ERROR << 16;
@@ -2285,7 +2282,7 @@ static int aac_start_stop(struct scsi_cmnd *scsicmd)
 	/*
 	 *	Allocate and initialize a Fib
 	 */
-	cmd_fibcontext = aac_fib_alloc(aac);
+	cmd_fibcontext = aac_fib_alloc_tag(aac, scsicmd);
 	if (!cmd_fibcontext)
 		return SCSI_MLQUEUE_HOST_BUSY;
 
@@ -3157,7 +3154,6 @@ static void aac_srb_callback(void *context, struct fib * fibptr)
 	scsicmd->result |= le32_to_cpu(srbreply->scsi_status);
 
 	aac_fib_complete(fibptr);
-	aac_fib_free(fibptr);
 	scsicmd->scsi_done(scsicmd);
 }
 
@@ -3187,9 +3183,10 @@ static int aac_send_srb_fib(struct scsi_cmnd* scsicmd)
 	/*
 	 *	Allocate and initialize a Fib then setup a BlockWrite command
 	 */
-	if (!(cmd_fibcontext = aac_fib_alloc(dev))) {
+	cmd_fibcontext = aac_fib_alloc_tag(dev, scsicmd);
+	if (!cmd_fibcontext)
 		return -1;
-	}
+
 	status = aac_adapter_scsi(cmd_fibcontext, scsicmd);
 
 	/*

drivers/scsi/aacraid/aacraid.h

@@ -2114,6 +2114,7 @@ int aac_acquire_irq(struct aac_dev *dev);
 void aac_free_irq(struct aac_dev *dev);
 const char *aac_driverinfo(struct Scsi_Host *);
 struct fib *aac_fib_alloc(struct aac_dev *dev);
+struct fib *aac_fib_alloc_tag(struct aac_dev *dev, struct scsi_cmnd *scmd);
 int aac_fib_setup(struct aac_dev *dev);
 void aac_fib_map_free(struct aac_dev *dev);
 void aac_fib_free(struct fib * context);

drivers/scsi/aacraid/commsup.c

@@ -137,6 +137,7 @@ int aac_fib_setup(struct aac_dev * dev)
 		i++, fibptr++)
 	{
 		fibptr->flags = 0;
+		fibptr->size = sizeof(struct fib);
 		fibptr->dev = dev;
 		fibptr->hw_fib_va = hw_fib;
 		fibptr->data = (void *) fibptr->hw_fib_va->data;
@@ -156,12 +157,37 @@ int aac_fib_setup(struct aac_dev * dev)
 	 */
 	dev->fibs[dev->scsi_host_ptr->can_queue + AAC_NUM_MGT_FIB - 1].next = NULL;
 	/*
-	 *	Enable this to debug out of queue space
+	*	Set 8 fibs aside for management tools
 	*/
-	dev->free_fib = &dev->fibs[0];
+	dev->free_fib = &dev->fibs[dev->scsi_host_ptr->can_queue];
 	return 0;
 }
 
+/**
+ *	aac_fib_alloc_tag-allocate a fib using tags
+ *	@dev: Adapter to allocate the fib for
+ *
+ *	Allocate a fib from the adapter fib pool using tags
+ *	from the blk layer.
+ */
+
+struct fib *aac_fib_alloc_tag(struct aac_dev *dev, struct scsi_cmnd *scmd)
+{
+	struct fib *fibptr;
+
+	fibptr = &dev->fibs[scmd->request->tag];
+	/*
+	 *	Null out fields that depend on being zero at the start of
+	 *	each I/O
+	 */
+	fibptr->hw_fib_va->header.XferState = 0;
+	fibptr->type = FSAFS_NTC_FIB_CONTEXT;
+	fibptr->callback_data = NULL;
+	fibptr->callback = NULL;
+
+	return fibptr;
+}
+
 /**
  *	aac_fib_alloc	-	allocate a fib
  *	@dev: Adapter to allocate the fib for

drivers/scsi/aacraid/dpcsup.c

@@ -394,7 +394,6 @@ unsigned int aac_intr_normal(struct aac_dev *dev, u32 index,
 				fib->callback(fib->callback_data, fib);
 			} else {
 				aac_fib_complete(fib);
-				aac_fib_free(fib);
 			}
 		} else {
 			unsigned long flagv;
@@ -416,7 +415,6 @@ unsigned int aac_intr_normal(struct aac_dev *dev, u32 index,
 				fib->done = 0;
 				spin_unlock_irqrestore(&fib->event_lock, flagv);
 				aac_fib_complete(fib);
-				aac_fib_free(fib);
 			}
 
 		}

drivers/scsi/aacraid/linit.c

@@ -454,6 +454,8 @@ static int aac_slave_configure(struct scsi_device *sdev)
 	} else
 		scsi_change_queue_depth(sdev, 1);
 
+		sdev->tagged_supported = 1;
+
 	return 0;
 }