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, 13 insertions, 13 deletions

diff --git a/drivers/block/swim3.c b/drivers/block/swim3.c
index ba4809c9bdba..c7953860ce91 100644
--- a/drivers/block/swim3.c
+++ b/drivers/block/swim3.c
@@ -257,7 +257,7 @@ static unsigned int floppy_check_events(struct gendisk *disk,
 					unsigned int clearing);
 static int floppy_revalidate(struct gendisk *disk);
 
-static bool swim3_end_request(struct floppy_state *fs, int err, unsigned int nr_bytes)
+static bool swim3_end_request(struct floppy_state *fs, blk_status_t err, unsigned int nr_bytes)
 {
 	struct request *req = fs->cur_req;
 	int rc;
@@ -334,7 +334,7 @@ static void start_request(struct floppy_state *fs)
 		if (fs->mdev->media_bay &&
 		    check_media_bay(fs->mdev->media_bay) != MB_FD) {
 			swim3_dbg("%s", "  media bay absent, dropping req\n");
-			swim3_end_request(fs, -ENODEV, 0);
+			swim3_end_request(fs, BLK_STS_IOERR, 0);
 			continue;
 		}
 
@@ -350,12 +350,12 @@ static void start_request(struct floppy_state *fs)
 		if (blk_rq_pos(req) >= fs->total_secs) {
 			swim3_dbg("  pos out of bounds (%ld, max is %ld)\n",
 				  (long)blk_rq_pos(req), (long)fs->total_secs);
-			swim3_end_request(fs, -EIO, 0);
+			swim3_end_request(fs, BLK_STS_IOERR, 0);
 			continue;
 		}
 		if (fs->ejected) {
 			swim3_dbg("%s", "  disk ejected\n");
-			swim3_end_request(fs, -EIO, 0);
+			swim3_end_request(fs, BLK_STS_IOERR, 0);
 			continue;
 		}
 
@@ -364,7 +364,7 @@ static void start_request(struct floppy_state *fs)
 				fs->write_prot = swim3_readbit(fs, WRITE_PROT);
 			if (fs->write_prot) {
 				swim3_dbg("%s", "  try to write, disk write protected\n");
-				swim3_end_request(fs, -EIO, 0);
+				swim3_end_request(fs, BLK_STS_IOERR, 0);
 				continue;
 			}
 		}
@@ -548,7 +548,7 @@ static void act(struct floppy_state *fs)
 				if (fs->retries > 5) {
 					swim3_err("Wrong cylinder in transfer, want: %d got %d\n",
 						  fs->req_cyl, fs->cur_cyl);
-					swim3_end_request(fs, -EIO, 0);
+					swim3_end_request(fs, BLK_STS_IOERR, 0);
 					fs->state = idle;
 					return;
 				}
@@ -584,7 +584,7 @@ static void scan_timeout(unsigned long data)
 	out_8(&sw->intr_enable, 0);
 	fs->cur_cyl = -1;
 	if (fs->retries > 5) {
-		swim3_end_request(fs, -EIO, 0);
+		swim3_end_request(fs, BLK_STS_IOERR, 0);
 		fs->state = idle;
 		start_request(fs);
 	} else {
@@ -608,7 +608,7 @@ static void seek_timeout(unsigned long data)
 	out_8(&sw->select, RELAX);
 	out_8(&sw->intr_enable, 0);
 	swim3_err("%s", "Seek timeout\n");
-	swim3_end_request(fs, -EIO, 0);
+	swim3_end_request(fs, BLK_STS_IOERR, 0);
 	fs->state = idle;
 	start_request(fs);
 	spin_unlock_irqrestore(&swim3_lock, flags);
@@ -637,7 +637,7 @@ static void settle_timeout(unsigned long data)
 		goto unlock;
 	}
 	swim3_err("%s", "Seek settle timeout\n");
-	swim3_end_request(fs, -EIO, 0);
+	swim3_end_request(fs, BLK_STS_IOERR, 0);
 	fs->state = idle;
 	start_request(fs);
  unlock:
@@ -666,7 +666,7 @@ static void xfer_timeout(unsigned long data)
 	swim3_err("Timeout %sing sector %ld\n",
 	       (rq_data_dir(fs->cur_req)==WRITE? "writ": "read"),
 	       (long)blk_rq_pos(fs->cur_req));
-	swim3_end_request(fs, -EIO, 0);
+	swim3_end_request(fs, BLK_STS_IOERR, 0);
 	fs->state = idle;
 	start_request(fs);
 	spin_unlock_irqrestore(&swim3_lock, flags);
@@ -703,7 +703,7 @@ static irqreturn_t swim3_interrupt(int irq, void *dev_id)
 				swim3_err("%s", "Seen sector but cyl=ff?\n");
 				fs->cur_cyl = -1;
 				if (fs->retries > 5) {
-					swim3_end_request(fs, -EIO, 0);
+					swim3_end_request(fs, BLK_STS_IOERR, 0);
 					fs->state = idle;
 					start_request(fs);
 				} else {
@@ -786,7 +786,7 @@ static irqreturn_t swim3_interrupt(int irq, void *dev_id)
 				swim3_err("Error %sing block %ld (err=%x)\n",
 				       rq_data_dir(req) == WRITE? "writ": "read",
 				       (long)blk_rq_pos(req), err);
-				swim3_end_request(fs, -EIO, 0);
+				swim3_end_request(fs, BLK_STS_IOERR, 0);
 				fs->state = idle;
 			}
 		} else {
@@ -795,7 +795,7 @@ static irqreturn_t swim3_interrupt(int irq, void *dev_id)
 				swim3_err("fd dma error: stat=%x resid=%d\n", stat, resid);
 				swim3_err("  state=%d, dir=%x, intr=%x, err=%x\n",
 					  fs->state, rq_data_dir(req), intr, err);
-				swim3_end_request(fs, -EIO, 0);
+				swim3_end_request(fs, BLK_STS_IOERR, 0);
 				fs->state = idle;
 				start_request(fs);
 				break;