block: split out request-only flags into a new namespace

A lot of the REQ_* flags are only used on struct requests, and only of
use to the block layer and a few drivers that dig into struct request
internals.

This patch adds a new req_flags_t rq_flags field to struct request for
them, and thus dramatically shrinks the number of common requests.  It
also removes the unfortunate situation where we have to fit the fields
from the same enum into 32 bits for struct bio and 64 bits for
struct request.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Shaun Tancheff <shaun.tancheff@seagate.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 2cca9cf..8c52622 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -163,26 +163,11 @@
 {
 	__scsi_queue_insert(cmd, reason, 1);
 }
-/**
- * scsi_execute - insert request and wait for the result
- * @sdev:	scsi device
- * @cmd:	scsi command
- * @data_direction: data direction
- * @buffer:	data buffer
- * @bufflen:	len of buffer
- * @sense:	optional sense buffer
- * @timeout:	request timeout in seconds
- * @retries:	number of times to retry request
- * @flags:	or into request flags;
- * @resid:	optional residual length
- *
- * returns the req->errors value which is the scsi_cmnd result
- * field.
- */
-int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
+
+static int __scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
 		 int data_direction, void *buffer, unsigned bufflen,
 		 unsigned char *sense, int timeout, int retries, u64 flags,
-		 int *resid)
+		 req_flags_t rq_flags, int *resid)
 {
 	struct request *req;
 	int write = (data_direction == DMA_TO_DEVICE);
@@ -203,7 +188,8 @@
 	req->sense_len = 0;
 	req->retries = retries;
 	req->timeout = timeout;
-	req->cmd_flags |= flags | REQ_QUIET | REQ_PREEMPT;
+	req->cmd_flags |= flags;
+	req->rq_flags |= rq_flags | RQF_QUIET | RQF_PREEMPT;
 
 	/*
 	 * head injection *required* here otherwise quiesce won't work
@@ -227,12 +213,37 @@
 
 	return ret;
 }
+
+/**
+ * scsi_execute - insert request and wait for the result
+ * @sdev:	scsi device
+ * @cmd:	scsi command
+ * @data_direction: data direction
+ * @buffer:	data buffer
+ * @bufflen:	len of buffer
+ * @sense:	optional sense buffer
+ * @timeout:	request timeout in seconds
+ * @retries:	number of times to retry request
+ * @flags:	or into request flags;
+ * @resid:	optional residual length
+ *
+ * returns the req->errors value which is the scsi_cmnd result
+ * field.
+ */
+int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
+		 int data_direction, void *buffer, unsigned bufflen,
+		 unsigned char *sense, int timeout, int retries, u64 flags,
+		 int *resid)
+{
+	return __scsi_execute(sdev, cmd, data_direction, buffer, bufflen, sense,
+			timeout, retries, flags, 0, resid);
+}
 EXPORT_SYMBOL(scsi_execute);
 
 int scsi_execute_req_flags(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, u64 flags)
+		     int *resid, u64 flags, req_flags_t rq_flags)
 {
 	char *sense = NULL;
 	int result;
@@ -242,8 +253,8 @@
 		if (!sense)
 			return DRIVER_ERROR << 24;
 	}
-	result = scsi_execute(sdev, cmd, data_direction, buffer, bufflen,
-			      sense, timeout, retries, flags, resid);
+	result = __scsi_execute(sdev, cmd, data_direction, buffer, bufflen,
+			      sense, timeout, retries, flags, rq_flags, resid);
 	if (sshdr)
 		scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, sshdr);
 
@@ -813,7 +824,7 @@
 		 */
 		if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d))
 			;
-		else if (!(req->cmd_flags & REQ_QUIET))
+		else if (!(req->rq_flags & RQF_QUIET))
 			scsi_print_sense(cmd);
 		result = 0;
 		/* BLOCK_PC may have set error */
@@ -943,7 +954,7 @@
 	switch (action) {
 	case ACTION_FAIL:
 		/* Give up and fail the remainder of the request */
-		if (!(req->cmd_flags & REQ_QUIET)) {
+		if (!(req->rq_flags & RQF_QUIET)) {
 			static DEFINE_RATELIMIT_STATE(_rs,
 					DEFAULT_RATELIMIT_INTERVAL,
 					DEFAULT_RATELIMIT_BURST);
@@ -972,7 +983,7 @@
 		 * A new command will be prepared and issued.
 		 */
 		if (q->mq_ops) {
-			cmd->request->cmd_flags &= ~REQ_DONTPREP;
+			cmd->request->rq_flags &= ~RQF_DONTPREP;
 			scsi_mq_uninit_cmd(cmd);
 			scsi_mq_requeue_cmd(cmd);
 		} else {
@@ -1234,7 +1245,7 @@
 			/*
 			 * If the devices is blocked we defer normal commands.
 			 */
-			if (!(req->cmd_flags & REQ_PREEMPT))
+			if (!(req->rq_flags & RQF_PREEMPT))
 				ret = BLKPREP_DEFER;
 			break;
 		default:
@@ -1243,7 +1254,7 @@
 			 * special commands.  In particular any user initiated
 			 * command is not allowed.
 			 */
-			if (!(req->cmd_flags & REQ_PREEMPT))
+			if (!(req->rq_flags & RQF_PREEMPT))
 				ret = BLKPREP_KILL;
 			break;
 		}
@@ -1279,7 +1290,7 @@
 			blk_delay_queue(q, SCSI_QUEUE_DELAY);
 		break;
 	default:
-		req->cmd_flags |= REQ_DONTPREP;
+		req->rq_flags |= RQF_DONTPREP;
 	}
 
 	return ret;
@@ -1736,7 +1747,7 @@
 		 * we add the dev to the starved list so it eventually gets
 		 * a run when a tag is freed.
 		 */
-		if (blk_queue_tagged(q) && !(req->cmd_flags & REQ_QUEUED)) {
+		if (blk_queue_tagged(q) && !(req->rq_flags & RQF_QUEUED)) {
 			spin_lock_irq(shost->host_lock);
 			if (list_empty(&sdev->starved_entry))
 				list_add_tail(&sdev->starved_entry,
@@ -1903,11 +1914,11 @@
 		goto out_dec_target_busy;
 
 
-	if (!(req->cmd_flags & REQ_DONTPREP)) {
+	if (!(req->rq_flags & RQF_DONTPREP)) {
 		ret = prep_to_mq(scsi_mq_prep_fn(req));
 		if (ret)
 			goto out_dec_host_busy;
-		req->cmd_flags |= REQ_DONTPREP;
+		req->rq_flags |= RQF_DONTPREP;
 	} else {
 		blk_mq_start_request(req);
 	}
@@ -1952,7 +1963,7 @@
 		 * we hit an error, as we will never see this command
 		 * again.
 		 */
-		if (req->cmd_flags & REQ_DONTPREP)
+		if (req->rq_flags & RQF_DONTPREP)
 			scsi_mq_uninit_cmd(cmd);
 		break;
 	default: