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, 10 insertions, 10 deletions

diff --git a/drivers/block/sx8.c b/drivers/block/sx8.c
index c8e072caf56ff..08586dc14e853 100644
--- a/drivers/block/sx8.c
+++ b/drivers/block/sx8.c
@@ -745,7 +745,7 @@ static unsigned int carm_fill_get_fw_ver(struct carm_host *host,
 
 static inline void carm_end_request_queued(struct carm_host *host,
 					   struct carm_request *crq,
-					   int error)
+					   blk_status_t error)
 {
 	struct request *req = crq->rq;
 	int rc;
@@ -791,7 +791,7 @@ static inline void carm_round_robin(struct carm_host *host)
 }
 
 static inline void carm_end_rq(struct carm_host *host, struct carm_request *crq,
-			       int error)
+			       blk_status_t error)
 {
 	carm_end_request_queued(host, crq, error);
 	if (max_queue == 1)
@@ -869,14 +869,14 @@ queue_one_request:
 	sg = &crq->sg[0];
 	n_elem = blk_rq_map_sg(q, rq, sg);
 	if (n_elem <= 0) {
-		carm_end_rq(host, crq, -EIO);
+		carm_end_rq(host, crq, BLK_STS_IOERR);
 		return;		/* request with no s/g entries? */
 	}
 
 	/* map scatterlist to PCI bus addresses */
 	n_elem = pci_map_sg(host->pdev, sg, n_elem, pci_dir);
 	if (n_elem <= 0) {
-		carm_end_rq(host, crq, -EIO);
+		carm_end_rq(host, crq, BLK_STS_IOERR);
 		return;		/* request with no s/g entries? */
 	}
 	crq->n_elem = n_elem;
@@ -937,7 +937,7 @@ queue_one_request:
 
 static void carm_handle_array_info(struct carm_host *host,
 				   struct carm_request *crq, u8 *mem,
-				   int error)
+				   blk_status_t error)
 {
 	struct carm_port *port;
 	u8 *msg_data = mem + sizeof(struct carm_array_info);
@@ -997,7 +997,7 @@ out:
 
 static void carm_handle_scan_chan(struct carm_host *host,
 				  struct carm_request *crq, u8 *mem,
-				  int error)
+				  blk_status_t error)
 {
 	u8 *msg_data = mem + IOC_SCAN_CHAN_OFFSET;
 	unsigned int i, dev_count = 0;
@@ -1029,7 +1029,7 @@ out:
 }
 
 static void carm_handle_generic(struct carm_host *host,
-				struct carm_request *crq, int error,
+				struct carm_request *crq, blk_status_t error,
 				int cur_state, int next_state)
 {
 	DPRINTK("ENTER\n");
@@ -1045,7 +1045,7 @@ static void carm_handle_generic(struct carm_host *host,
 }
 
 static inline void carm_handle_rw(struct carm_host *host,
-				  struct carm_request *crq, int error)
+				  struct carm_request *crq, blk_status_t error)
 {
 	int pci_dir;
 
@@ -1067,7 +1067,7 @@ static inline void carm_handle_resp(struct carm_host *host,
 	u32 handle = le32_to_cpu(ret_handle_le);
 	unsigned int msg_idx;
 	struct carm_request *crq;
-	int error = (status == RMSG_OK) ? 0 : -EIO;
+	blk_status_t error = (status == RMSG_OK) ? 0 : BLK_STS_IOERR;
 	u8 *mem;
 
 	VPRINTK("ENTER, handle == 0x%x\n", handle);
@@ -1155,7 +1155,7 @@ static inline void carm_handle_resp(struct carm_host *host,
 err_out:
 	printk(KERN_WARNING DRV_NAME "(%s): BUG: unhandled message type %d/%d\n",
 	       pci_name(host->pdev), crq->msg_type, crq->msg_subtype);
-	carm_end_rq(host, crq, -EIO);
+	carm_end_rq(host, crq, BLK_STS_IOERR);
 }
 
 static inline void carm_handle_responses(struct carm_host *host)