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>

1 files changed, 6 insertions, 5 deletions

diff --git a/drivers/block/ps3disk.c b/drivers/block/ps3disk.c
index a809e3e9feb8..075662f2cf46 100644
--- a/drivers/block/ps3disk.c
+++ b/drivers/block/ps3disk.c
@@ -158,7 +158,7 @@ static int ps3disk_submit_request_sg(struct ps3_storage_device *dev,
 	if (res) {
 		dev_err(&dev->sbd.core, "%s:%u: %s failed %d\n", __func__,
 			__LINE__, op, res);
-		__blk_end_request_all(req, -EIO);
+		__blk_end_request_all(req, BLK_STS_IOERR);
 		return 0;
 	}
 
@@ -180,7 +180,7 @@ static int ps3disk_submit_flush_request(struct ps3_storage_device *dev,
 	if (res) {
 		dev_err(&dev->sbd.core, "%s:%u: sync cache failed 0x%llx\n",
 			__func__, __LINE__, res);
-		__blk_end_request_all(req, -EIO);
+		__blk_end_request_all(req, BLK_STS_IOERR);
 		return 0;
 	}
 
@@ -208,7 +208,7 @@ static void ps3disk_do_request(struct ps3_storage_device *dev,
 			break;
 		default:
 			blk_dump_rq_flags(req, DEVICE_NAME " bad request");
-			__blk_end_request_all(req, -EIO);
+			__blk_end_request_all(req, BLK_STS_IOERR);
 		}
 	}
 }
@@ -231,7 +231,8 @@ static irqreturn_t ps3disk_interrupt(int irq, void *data)
 	struct ps3_storage_device *dev = data;
 	struct ps3disk_private *priv;
 	struct request *req;
-	int res, read, error;
+	int res, read;
+	blk_status_t error;
 	u64 tag, status;
 	const char *op;
 
@@ -269,7 +270,7 @@ static irqreturn_t ps3disk_interrupt(int irq, void *data)
 	if (status) {
 		dev_dbg(&dev->sbd.core, "%s:%u: %s failed 0x%llx\n", __func__,
 			__LINE__, op, status);
-		error = -EIO;
+		error = BLK_STS_IOERR;
 	} else {
 		dev_dbg(&dev->sbd.core, "%s:%u: %s completed\n", __func__,
 			__LINE__, op);