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>

3 files changed, 14 insertions, 14 deletions

diff --git a/drivers/block/paride/pcd.c b/drivers/block/paride/pcd.c
index b1267ef34d5a..cffe42d80ce9 100644
--- a/drivers/block/paride/pcd.c
+++ b/drivers/block/paride/pcd.c
@@ -783,7 +783,7 @@ static void pcd_request(void)
 			ps_set_intr(do_pcd_read, NULL, 0, nice);
 			return;
 		} else {
-			__blk_end_request_all(pcd_req, -EIO);
+			__blk_end_request_all(pcd_req, BLK_STS_IOERR);
 			pcd_req = NULL;
 		}
 	}
@@ -794,7 +794,7 @@ static void do_pcd_request(struct request_queue *q)
 	pcd_request();
 }
 
-static inline void next_request(int err)
+static inline void next_request(blk_status_t err)
 {
 	unsigned long saved_flags;
 
@@ -837,7 +837,7 @@ static void pcd_start(void)
 
 	if (pcd_command(pcd_current, rd_cmd, 2048, "read block")) {
 		pcd_bufblk = -1;
-		next_request(-EIO);
+		next_request(BLK_STS_IOERR);
 		return;
 	}
 
@@ -871,7 +871,7 @@ static void do_pcd_read_drq(void)
 			return;
 		}
 		pcd_bufblk = -1;
-		next_request(-EIO);
+		next_request(BLK_STS_IOERR);
 		return;
 	}
 
diff --git a/drivers/block/paride/pd.c b/drivers/block/paride/pd.c
index 7d2402f90978..c98983be4f9c 100644
--- a/drivers/block/paride/pd.c
+++ b/drivers/block/paride/pd.c
@@ -438,7 +438,7 @@ static void run_fsm(void)
 				phase = NULL;
 				spin_lock_irqsave(&pd_lock, saved_flags);
 				if (!__blk_end_request_cur(pd_req,
-						res == Ok ? 0 : -EIO)) {
+						res == Ok ? 0 : BLK_STS_IOERR)) {
 					if (!set_next_request())
 						stop = 1;
 				}
diff --git a/drivers/block/paride/pf.c b/drivers/block/paride/pf.c
index f24ca7315ddc..5f46da8d05cd 100644
--- a/drivers/block/paride/pf.c
+++ b/drivers/block/paride/pf.c
@@ -801,7 +801,7 @@ static int set_next_request(void)
 	return pf_req != NULL;
 }
 
-static void pf_end_request(int err)
+static void pf_end_request(blk_status_t err)
 {
 	if (pf_req && !__blk_end_request_cur(pf_req, err))
 		pf_req = NULL;
@@ -821,7 +821,7 @@ repeat:
 	pf_count = blk_rq_cur_sectors(pf_req);
 
 	if (pf_block + pf_count > get_capacity(pf_req->rq_disk)) {
-		pf_end_request(-EIO);
+		pf_end_request(BLK_STS_IOERR);
 		goto repeat;
 	}
 
@@ -836,7 +836,7 @@ repeat:
 		pi_do_claimed(pf_current->pi, do_pf_write);
 	else {
 		pf_busy = 0;
-		pf_end_request(-EIO);
+		pf_end_request(BLK_STS_IOERR);
 		goto repeat;
 	}
 }
@@ -868,7 +868,7 @@ static int pf_next_buf(void)
 	return 0;
 }
 
-static inline void next_request(int err)
+static inline void next_request(blk_status_t err)
 {
 	unsigned long saved_flags;
 
@@ -896,7 +896,7 @@ static void do_pf_read_start(void)
 			pi_do_claimed(pf_current->pi, do_pf_read_start);
 			return;
 		}
-		next_request(-EIO);
+		next_request(BLK_STS_IOERR);
 		return;
 	}
 	pf_mask = STAT_DRQ;
@@ -915,7 +915,7 @@ static void do_pf_read_drq(void)
 				pi_do_claimed(pf_current->pi, do_pf_read_start);
 				return;
 			}
-			next_request(-EIO);
+			next_request(BLK_STS_IOERR);
 			return;
 		}
 		pi_read_block(pf_current->pi, pf_buf, 512);
@@ -942,7 +942,7 @@ static void do_pf_write_start(void)
 			pi_do_claimed(pf_current->pi, do_pf_write_start);
 			return;
 		}
-		next_request(-EIO);
+		next_request(BLK_STS_IOERR);
 		return;
 	}
 
@@ -955,7 +955,7 @@ static void do_pf_write_start(void)
 				pi_do_claimed(pf_current->pi, do_pf_write_start);
 				return;
 			}
-			next_request(-EIO);
+			next_request(BLK_STS_IOERR);
 			return;
 		}
 		pi_write_block(pf_current->pi, pf_buf, 512);
@@ -975,7 +975,7 @@ static void do_pf_write_done(void)
 			pi_do_claimed(pf_current->pi, do_pf_write_start);
 			return;
 		}
-		next_request(-EIO);
+		next_request(BLK_STS_IOERR);
 		return;
 	}
 	pi_disconnect(pf_current->pi);