block: introduce new block status code type

Currently we use nornal Linux errno values in the block layer, and while
we accept any error a few have overloaded magic meanings.  This patch
instead introduces a new  blk_status_t value that holds block layer specific
status codes and explicitly explains their meaning.  Helpers to convert from
and to the previous special meanings are provided for now, but I suspect
we want to get rid of them in the long run - those drivers that have a
errno input (e.g. networking) usually get errnos that don't know about
the special block layer overloads, and similarly returning them to userspace
will usually return somethings that strictly speaking isn't correct
for file system operations, but that's left as an exercise for later.

For now the set of errors is a very limited set that closely corresponds
to the previous overloaded errno values, but there is some low hanging
fruite to improve it.

blk_status_t (ab)uses the sparse __bitwise annotations to allow for sparse
typechecking, so that we can easily catch places passing the wrong values.

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

2 files changed, 9 insertions, 9 deletions

diff --git a/drivers/block/mtip32xx/mtip32xx.c b/drivers/block/mtip32xx/mtip32xx.c
index 3a779a4f5653..ee6f66bb50c7 100644
--- a/drivers/block/mtip32xx/mtip32xx.c
+++ b/drivers/block/mtip32xx/mtip32xx.c
@@ -532,7 +532,7 @@ static int mtip_read_log_page(struct mtip_port *port, u8 page, u16 *buffer,
 static int mtip_get_smart_attr(struct mtip_port *port, unsigned int id,
 						struct smart_attr *attrib);
 
-static void mtip_complete_command(struct mtip_cmd *cmd, int status)
+static void mtip_complete_command(struct mtip_cmd *cmd, blk_status_t status)
 {
 	struct request *req = blk_mq_rq_from_pdu(cmd);
 
@@ -568,7 +568,7 @@ static void mtip_handle_tfe(struct driver_data *dd)
 	if (test_bit(MTIP_PF_IC_ACTIVE_BIT, &port->flags)) {
 		cmd = mtip_cmd_from_tag(dd, MTIP_TAG_INTERNAL);
 		dbg_printk(MTIP_DRV_NAME " TFE for the internal command\n");
-		mtip_complete_command(cmd, -EIO);
+		mtip_complete_command(cmd, BLK_STS_IOERR);
 		return;
 	}
 
@@ -667,7 +667,7 @@ static void mtip_handle_tfe(struct driver_data *dd)
 					tag,
 					fail_reason != NULL ?
 						fail_reason : "unknown");
-					mtip_complete_command(cmd, -ENODATA);
+					mtip_complete_command(cmd, BLK_STS_MEDIUM);
 					continue;
 				}
 			}
@@ -690,7 +690,7 @@ static void mtip_handle_tfe(struct driver_data *dd)
 			dev_warn(&port->dd->pdev->dev,
 				"retiring tag %d\n", tag);
 
-			mtip_complete_command(cmd, -EIO);
+			mtip_complete_command(cmd, BLK_STS_IOERR);
 		}
 	}
 	print_tags(dd, "reissued (TFE)", tagaccum, cmd_cnt);
@@ -2753,7 +2753,7 @@ static void mtip_abort_cmd(struct request *req, void *data,
 	dbg_printk(MTIP_DRV_NAME " Aborting request, tag = %d\n", req->tag);
 
 	clear_bit(req->tag, dd->port->cmds_to_issue);
-	cmd->status = -EIO;
+	cmd->status = BLK_STS_IOERR;
 	mtip_softirq_done_fn(req);
 }
 
@@ -3597,7 +3597,7 @@ static int mtip_submit_request(struct blk_mq_hw_ctx *hctx, struct request *rq)
 		int err;
 
 		err = mtip_send_trim(dd, blk_rq_pos(rq), blk_rq_sectors(rq));
-		blk_mq_end_request(rq, err);
+		blk_mq_end_request(rq, err ? BLK_STS_IOERR : BLK_STS_OK);
 		return 0;
 	}
 
@@ -3730,7 +3730,7 @@ static enum blk_eh_timer_return mtip_cmd_timeout(struct request *req,
 	if (reserved) {
 		struct mtip_cmd *cmd = blk_mq_rq_to_pdu(req);
 
-		cmd->status = -ETIME;
+		cmd->status = BLK_STS_TIMEOUT;
 		return BLK_EH_HANDLED;
 	}
 
@@ -3961,7 +3961,7 @@ static void mtip_no_dev_cleanup(struct request *rq, void *data, bool reserv)
 {
 	struct mtip_cmd *cmd = blk_mq_rq_to_pdu(rq);
 
-	cmd->status = -ENODEV;
+	cmd->status = BLK_STS_IOERR;
 	blk_mq_complete_request(rq);
 }
 
diff --git a/drivers/block/mtip32xx/mtip32xx.h b/drivers/block/mtip32xx/mtip32xx.h
index 37b8e3e0bb78..e8286af50e16 100644
--- a/drivers/block/mtip32xx/mtip32xx.h
+++ b/drivers/block/mtip32xx/mtip32xx.h
@@ -342,7 +342,7 @@ struct mtip_cmd {
 	int retries; /* The number of retries left for this command. */
 
 	int direction; /* Data transfer direction */
-	int status;
+	blk_status_t status;
 };
 
 /* Structure used to describe a port. */