[PATCH v2 01/15] scsi: Add struct for args to execution functions

[Mike Christie <michael.christie@oracle.com>]

This begins to move the SCSI execution functions to use a struct for
passing in optional args. This patch adds the new struct, temporarily
converts scsi_execute and scsi_execute_req and add two helpers:
1. scsi_execute_args which takes the scsi_exec_args struct.
2. scsi_execute_cmd does not support the scsi_exec_args struct.

The next patches will convert scsi_execute and scsi_execute_req users to
the new helpers then remove scsi_execute and scsi_execute_req.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
---
 drivers/scsi/scsi_lib.c    | 40 ++++++++--------------
 include/scsi/scsi_device.h | 70 ++++++++++++++++++++++++++++++--------
 2 files changed, 71 insertions(+), 39 deletions(-)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index a29d87e57430..f76acb468abb 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -185,39 +185,29 @@ void scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
 	__scsi_queue_insert(cmd, reason, true);
 }
 
-
 /**
  * __scsi_execute - insert request and wait for the result
- * @sdev:	scsi device
+ * @sdev:	scsi_device
  * @cmd:	scsi command
- * @data_direction: data direction
+ * @opf:	block layer request cmd_flags
  * @buffer:	data buffer
  * @bufflen:	len of buffer
- * @sense:	optional sense buffer
- * @sshdr:	optional decoded sense header
  * @timeout:	request timeout in HZ
  * @retries:	number of times to retry request
- * @flags:	flags for ->cmd_flags
- * @rq_flags:	flags for ->rq_flags
- * @resid:	optional residual length
+ * @args:	Optional args. See struct definition for field descriptions
  *
  * Returns the scsi_cmnd result field if a command was executed, or a negative
  * Linux error code if we didn't get that far.
  */
 int __scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
-		 int data_direction, void *buffer, unsigned bufflen,
-		 unsigned char *sense, struct scsi_sense_hdr *sshdr,
-		 int timeout, int retries, blk_opf_t flags,
-		 req_flags_t rq_flags, int *resid)
+		   blk_opf_t opf, void *buffer, unsigned int bufflen,
+		   int timeout, int retries, const struct scsi_exec_args args)
 {
 	struct request *req;
 	struct scsi_cmnd *scmd;
 	int ret;
 
-	req = scsi_alloc_request(sdev->request_queue,
-			data_direction == DMA_TO_DEVICE ?
-			REQ_OP_DRV_OUT : REQ_OP_DRV_IN,
-			rq_flags & RQF_PM ? BLK_MQ_REQ_PM : 0);
+	req = scsi_alloc_request(sdev->request_queue, opf, args.req_flags);
 	if (IS_ERR(req))
 		return PTR_ERR(req);
 
@@ -232,8 +222,7 @@ int __scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
 	memcpy(scmd->cmnd, cmd, scmd->cmd_len);
 	scmd->allowed = retries;
 	req->timeout = timeout;
-	req->cmd_flags |= flags;
-	req->rq_flags |= rq_flags | RQF_QUIET;
+	req->rq_flags |= RQF_QUIET;
 
 	/*
 	 * head injection *required* here otherwise quiesce won't work
@@ -249,13 +238,14 @@ int __scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
 	if (unlikely(scmd->resid_len > 0 && scmd->resid_len <= bufflen))
 		memset(buffer + bufflen - scmd->resid_len, 0, scmd->resid_len);
 
-	if (resid)
-		*resid = scmd->resid_len;
-	if (sense && scmd->sense_len)
-		memcpy(sense, scmd->sense_buffer, SCSI_SENSE_BUFFERSIZE);
-	if (sshdr)
-		scsi_normalize_sense(scmd->sense_buffer, scmd->sense_len,
-				     sshdr);
+	if (args.resid)
+		*args.resid = scmd->resid_len;
+	if (args.sense && scmd->sense_len)
+		memcpy(args.sense, scmd->sense_buffer, SCSI_SENSE_BUFFERSIZE);
+	if (args.sshdr)
+		scsi_normalize_sense(scmd->sense_buffer,
+				     scmd->sense_len, args.sshdr);
+
 	ret = scmd->result;
  out:
 	blk_mq_free_request(req);
diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index 3642b8e3928b..eb960aa73b3b 100644
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -455,28 +455,70 @@ extern const char *scsi_device_state_name(enum scsi_device_state);
 extern int scsi_is_sdev_device(const struct device *);
 extern int scsi_is_target_device(const struct device *);
 extern void scsi_sanitize_inquiry_string(unsigned char *s, int len);
-extern int __scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
-			int data_direction, void *buffer, unsigned bufflen,
-			unsigned char *sense, struct scsi_sense_hdr *sshdr,
-			int timeout, int retries, blk_opf_t flags,
-			req_flags_t rq_flags, int *resid);
+
+/* Optional arguments to __scsi_execute */
+struct scsi_exec_args {
+	unsigned char *sense;		/* sense buffer */
+	unsigned int sense_len;		/* sense buffer len */
+	struct scsi_sense_hdr *sshdr;	/* decoded sense header */
+	blk_mq_req_flags_t req_flags;	/* BLK_MQ_REQ flags */
+	int *resid;			/* residual length */
+};
+
+int __scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
+		   blk_opf_t opf, void *buffer, unsigned int bufflen,
+		   int timeout, int retries, const struct scsi_exec_args args);
+
+#define scsi_execute_args(sdev, cmd, opf, buffer, bufflen, timeout,	\
+			  retries, args)				\
+({									\
+	BUILD_BUG_ON(args.sense &&					\
+		     args.sense_len != SCSI_SENSE_BUFFERSIZE);		\
+	__scsi_execute(sdev, cmd, opf, buffer, bufflen, timeout,	\
+		       retries, args);					\
+})
+
+#define scsi_execute_cmd(sdev, cmd, opf, buffer, bufflen, timeout,	\
+			 retries)					\
+({									\
+	struct scsi_exec_args exec_args = {};				\
+									\
+	__scsi_execute(sdev, cmd, opf, buffer, bufflen, timeout,	\
+		       retries, exec_args);				\
+})
+
 /* Make sure any sense buffer is the correct size. */
-#define scsi_execute(sdev, cmd, data_direction, buffer, bufflen, sense,	\
-		     sshdr, timeout, retries, flags, rq_flags, resid)	\
+#define scsi_execute(_sdev, _cmd, _data_dir, _buffer, _bufflen, _sense,	\
+		     _sshdr, _timeout, _retries, _flags, _rq_flags,	\
+		     _resid)						\
 ({									\
-	BUILD_BUG_ON((sense) != NULL &&					\
-		     sizeof(sense) != SCSI_SENSE_BUFFERSIZE);		\
-	__scsi_execute(sdev, cmd, data_direction, buffer, bufflen,	\
-		       sense, sshdr, timeout, retries, flags, rq_flags,	\
-		       resid);						\
+	BUILD_BUG_ON((_sense) != NULL &&				\
+		     sizeof(_sense) != SCSI_SENSE_BUFFERSIZE);		\
+	__scsi_execute(_sdev, _cmd, (_data_dir == DMA_TO_DEVICE ?	\
+		       REQ_OP_DRV_OUT : REQ_OP_DRV_IN) | _flags,	\
+		       _buffer, _bufflen, _timeout, _retries,	\
+		       (struct scsi_exec_args) {			\
+				.sense = _sense,			\
+				.sshdr = _sshdr,			\
+				.req_flags = _rq_flags & RQF_PM  ?	\
+						BLK_MQ_REQ_PM : 0,	\
+				.resid = _resid,			\
+		       });						\
 })
+
 static inline int scsi_execute_req(struct scsi_device *sdev,
 	const unsigned char *cmd, int data_direction, void *buffer,
 	unsigned bufflen, struct scsi_sense_hdr *sshdr, int timeout,
 	int retries, int *resid)
 {
-	return scsi_execute(sdev, cmd, data_direction, buffer,
-		bufflen, NULL, sshdr, timeout, retries,  0, 0, resid);
+	return __scsi_execute(sdev, cmd,
+			      data_direction == DMA_TO_DEVICE ?
+			      REQ_OP_DRV_OUT : REQ_OP_DRV_IN, buffer,
+			      bufflen, timeout, retries,
+			      (struct scsi_exec_args) {
+					.sshdr = sshdr,
+					.resid = resid,
+			      });
 }
 extern void sdev_disable_disk_events(struct scsi_device *sdev);
 extern void sdev_enable_disk_events(struct scsi_device *sdev);
-- 
2.25.1