block: split scsi_request out of struct request

And require all drivers that want to support BLOCK_PC to allocate it
as the first thing of their private data.  To support this the legacy
IDE and BSG code is switched to set cmd_size on their queues to let
the block layer allocate the additional space.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

4 files changed, 39 insertions, 14 deletions

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 461b7cf6af1d..e4c5f284fe2d 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -128,8 +128,6 @@ typedef __u32 __bitwise req_flags_t;
 #define RQF_NOMERGE_FLAGS \
 	(RQF_STARTED | RQF_SOFTBARRIER | RQF_FLUSH_SEQ | RQF_SPECIAL_PAYLOAD)
 
-#define BLK_MAX_CDB	16
-
 /*
  * Try to put the fields that are referenced together in the same cacheline.
  *
@@ -227,17 +225,7 @@ struct request {
 
 	int errors;
 
-	/*
-	 * when request is used as a packet command carrier
-	 */
-	unsigned char __cmd[BLK_MAX_CDB];
-	unsigned char *cmd;
-	unsigned short cmd_len;
-
 	unsigned int extra_len;	/* length of alignment and padding */
-	unsigned int sense_len;
-	unsigned int resid_len;	/* residual count */
-	void *sense;
 
 	unsigned long deadline;
 	struct list_head timeout_list;
@@ -925,7 +913,6 @@ extern void blk_rq_init(struct request_queue *q, struct request *rq);
 extern void blk_put_request(struct request *);
 extern void __blk_put_request(struct request_queue *, struct request *);
 extern struct request *blk_get_request(struct request_queue *, int, gfp_t);
-extern void blk_rq_set_block_pc(struct request *);
 extern void blk_requeue_request(struct request_queue *, struct request *);
 extern int blk_lld_busy(struct request_queue *q);
 extern int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
diff --git a/include/linux/ide.h b/include/linux/ide.h
index a633898f36ac..086fbe172817 100644
--- a/include/linux/ide.h
+++ b/include/linux/ide.h
@@ -20,6 +20,7 @@
 #include <linux/mutex.h>
 /* for request_sense */
 #include <linux/cdrom.h>
+#include <scsi/scsi_cmnd.h>
 #include <asm/byteorder.h>
 #include <asm/io.h>
 
@@ -52,6 +53,11 @@ enum ata_cmd_type_bits {
 	((rq)->cmd_type == REQ_TYPE_ATA_PM_SUSPEND || \
 	 (rq)->cmd_type == REQ_TYPE_ATA_PM_RESUME)
 
+struct ide_request {
+	struct scsi_request sreq;
+	u8 sense[SCSI_SENSE_BUFFERSIZE];
+};
+
 /* Error codes returned in rq->errors to the higher part of the driver. */
 enum {
 	IDE_DRV_ERROR_GENERAL	= 101,
@@ -579,7 +585,7 @@ struct ide_drive_s {
 
 	/* current sense rq and buffer */
 	bool sense_rq_armed;
-	struct request sense_rq;
+	struct request *sense_rq;
 	struct request_sense sense_data;
 };
 
diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
index 9fc1aecfc813..f708f1acfc50 100644
--- a/include/scsi/scsi_cmnd.h
+++ b/include/scsi/scsi_cmnd.h
@@ -8,6 +8,7 @@
 #include <linux/timer.h>
 #include <linux/scatterlist.h>
 #include <scsi/scsi_device.h>
+#include <scsi/scsi_request.h>
 
 struct Scsi_Host;
 struct scsi_driver;
@@ -57,6 +58,7 @@ struct scsi_pointer {
 #define SCMD_TAGGED		(1 << 0)
 
 struct scsi_cmnd {
+	struct scsi_request req;
 	struct scsi_device *device;
 	struct list_head list;  /* scsi_cmnd participates in queue lists */
 	struct list_head eh_entry; /* entry for the host eh_cmd_q */
diff --git a/include/scsi/scsi_request.h b/include/scsi/scsi_request.h
new file mode 100644
index 000000000000..ba0aeb980f7e
--- /dev/null
+++ b/include/scsi/scsi_request.h
@@ -0,0 +1,30 @@
+#ifndef _SCSI_SCSI_REQUEST_H
+#define _SCSI_SCSI_REQUEST_H
+
+#include <linux/blk-mq.h>
+
+#define BLK_MAX_CDB	16
+
+struct scsi_request {
+	unsigned char	__cmd[BLK_MAX_CDB];
+	unsigned char	*cmd;
+	unsigned short	cmd_len;
+	unsigned int	sense_len;
+	unsigned int	resid_len;	/* residual count */
+	void		*sense;
+};
+
+static inline struct scsi_request *scsi_req(struct request *rq)
+{
+	return blk_mq_rq_to_pdu(rq);
+}
+
+static inline void scsi_req_free_cmd(struct scsi_request *req)
+{
+	if (req->cmd != req->__cmd)
+		kfree(req->cmd);
+}
+
+void scsi_req_init(struct request *);
+
+#endif /* _SCSI_SCSI_REQUEST_H */