scsi: core: Call scsi_done directly

Conditional statements are faster than indirect calls. Hence call
scsi_done() directly. Since this patch removes the last user of the
scsi_done member, also remove that data structure member.

Link: https://lore.kernel.org/r/20211007204618.2196847-11-bvanassche@acm.orgReviewed-by: Benjamin Block <bblock@linux.ibm.com>
Reviewed-by: Bean Huo <beanhuo@micron.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/hosts.c

@@ -667,7 +667,7 @@ static bool complete_all_cmds_iter(struct request *rq, void *data, bool rsvd)
 	scsi_dma_unmap(scmd);
 	scmd->result = 0;
 	set_host_byte(scmd, status);
-	scmd->scsi_done(scmd);
+	scsi_done(scmd);
 	return true;
 }
 

drivers/scsi/scsi_lib.c

@@ -1520,7 +1520,7 @@ static int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
 
 	return rtn;
  done:
-	cmd->scsi_done(cmd);
+	scsi_done(cmd);
 	return 0;
 }
 
@@ -1694,7 +1694,6 @@ static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
 	scsi_set_resid(cmd, 0);
 	memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
 	cmd->submitter = SUBMITTED_BY_BLOCK_LAYER;
-	cmd->scsi_done = scsi_done;
 
 	blk_mq_start_request(req);
 	reason = scsi_dispatch_cmd(cmd);

include/scsi/scsi_cmnd.h

@@ -123,10 +123,6 @@ struct scsi_cmnd {
 				 * command (auto-sense). Length must be
 				 * SCSI_SENSE_BUFFERSIZE bytes. */
 
-	/* Low-level done function - can be used by low-level driver to point
-	 *        to completion function.  Not used by mid/upper level code. */
-	void (*scsi_done) (struct scsi_cmnd *);
-
 	/*
 	 * The following fields can be written to by the host specific code. 
 	 * Everything else should be left alone. 

include/scsi/scsi_host.h

@@ -516,7 +516,7 @@ struct scsi_host_template {
 		unsigned long irq_flags;				\
 		int rc;							\
 		spin_lock_irqsave(shost->host_lock, irq_flags);		\
-		rc = func_name##_lck (cmd, cmd->scsi_done);			\
+		rc = func_name##_lck(cmd, scsi_done);			\
 		spin_unlock_irqrestore(shost->host_lock, irq_flags);	\
 		return rc;						\
 	}