[PATCH 2/2] block: add more debug data to print_req_err

[Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>]

This patch adds more debug data on the top of the existing
print_req_error() where we enhance the print message with the printing
request operations in string format and other request fields.

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
---
 block/blk-core.c | 57 +++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 54 insertions(+), 3 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index d1a227cfb72e..659e5ea6f6c9 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -167,6 +167,54 @@ int blk_status_to_errno(blk_status_t status)
 }
 EXPORT_SYMBOL_GPL(blk_status_to_errno);
 
+static inline const char *req_op_str(struct request *req)
+{
+       char *ret;
+
+       switch (req_op(req)) {
+       case REQ_OP_READ:
+               ret = "read";
+               break;
+       case REQ_OP_WRITE:
+               ret = "write";
+               break;
+       case REQ_OP_FLUSH:
+               ret = "flush";
+               break;
+       case REQ_OP_DISCARD:
+               ret = "discard";
+               break;
+       case REQ_OP_SECURE_ERASE:
+               ret = "secure_erase";
+               break;
+       case REQ_OP_ZONE_RESET:
+               ret = "zone_reset";
+               break;
+       case REQ_OP_WRITE_SAME:
+               ret = "write_same";
+               break;
+       case REQ_OP_WRITE_ZEROES:
+               ret = "write_zeroes";
+               break;
+       case REQ_OP_SCSI_IN:
+               ret = "scsi_in";
+               break;
+       case REQ_OP_SCSI_OUT:
+               ret = "scsi_out";
+               break;
+       case REQ_OP_DRV_IN:
+               ret = "drv_in";
+               break;
+       case REQ_OP_DRV_OUT:
+               ret = "drv_out";
+               break;
+       default:
+               ret = "unknown";
+       }
+
+       return ret;
+}
+
 static void print_req_error(struct request *req, blk_status_t status,
 		const char *caller)
 {
@@ -176,11 +224,14 @@ static void print_req_error(struct request *req, blk_status_t status,
 		return;
 
 	printk_ratelimited(KERN_ERR
-		"%s: %s error, dev %s, sector %llu op 0x%x flags 0x%x\n",
+		"%s: %s error, dev %s, sector %llu op 0x%x:(%s) flags 0x%x "
+		"phys_seg %u prio class %u\n",
 		caller, blk_errors[idx].name,
 		req->rq_disk ?  req->rq_disk->disk_name : "?",
-		blk_rq_pos(req), req_op(req),
-		req->cmd_flags & ~REQ_OP_MASK);
+		blk_rq_pos(req), req_op(req), req_op_str(req),
+		req->cmd_flags & ~REQ_OP_MASK,
+		req->nr_phys_segments,
+		IOPRIO_PRIO_CLASS(req->ioprio));
 }
 
 static void req_bio_endio(struct request *rq, struct bio *bio,
-- 
2.19.1