[RFC PATCH 2/4] convert dm to blkerr error values

[Mike Christie <michaelc@cs.wisc.edu>]

Convert dm and dm-targets (excpet dm-multipath) to
BLKERR values.

Some temporary crap I will fix is the dec_pending fucntions.
Becuase dec_pending() used to get -Exyz values from target map
functions I just added a switch statement to convert the Exyz
value to a BLKERR one. I need to spend more time looking at
some of them to make sure I do the right thing. I will convert
the target's map functions in the next round - unless you are
fine with that conversion code in dec_pending. I had to play
similar tricks for the other target's dec_pending/count functions.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -436,8 +436,8 @@ static void dec_pending(struct crypt_io 
 {
 	struct crypt_config *cc = (struct crypt_config *) io->target->private;
 
-	if (error < 0)
-		io->error = error;
+	if (error && io->error != BLK_SUCCESS)
+		io->error = BLKERR_IO;
 
 	if (!atomic_dec_and_test(&io->pending))
 		return;
@@ -726,7 +726,10 @@ static int crypt_endio(struct bio *bio, 
 	}
 
 	if (bio->bi_size)
-		return 1;
+		return -1;
+
+	if (error != BLK_SUCCESS)
+		io->error = error;
 
 	bio_put(bio);
 
@@ -804,7 +807,7 @@ static int crypt_map(struct dm_target *t
 	io->target = ti;
 	io->bio = bio;
 	io->first_clone = NULL;
-	io->error = 0;
+	io->error = BLK_SUCCESS;
 	atomic_set(&io->pending, 1); /* hold a reference */
 
 	if (bio_data_dir(bio) == WRITE)
diff --git a/drivers/md/dm-emc.c b/drivers/md/dm-emc.c
--- a/drivers/md/dm-emc.c
+++ b/drivers/md/dm-emc.c
@@ -48,7 +48,7 @@ static int emc_endio(struct bio *bio, un
 	 *
 	 * For now simple logic: either it works or it doesn't.
 	 */
-	if (error)
+	if (error != BLK_SUCCESS)
 		dm_pg_init_complete(path, MP_FAIL_PATH);
 	else
 		dm_pg_init_complete(path, 0);
diff --git a/drivers/md/dm-io.c b/drivers/md/dm-io.c
--- a/drivers/md/dm-io.c
+++ b/drivers/md/dm-io.c
@@ -115,7 +115,7 @@ static inline unsigned bio_get_region(st
  *---------------------------------------------------------------*/
 static void dec_count(struct io *io, unsigned int region, int error)
 {
-	if (error)
+	if (error != BLK_SUCCESS)
 		set_bit(region, &io->error);
 
 	if (atomic_dec_and_test(&io->count)) {
@@ -141,7 +141,7 @@ static int endio(struct bio *bio, unsign
 	if (bio->bi_size)
 		return 1;
 
-	if (error && bio_data_dir(bio) == READ)
+	if (error != BLK_SUCCESS && bio_data_dir(bio) == READ)
 		zero_fill_bio(bio);
 
 	dec_count(io, bio_get_region(bio), error);
@@ -308,7 +308,7 @@ static void dispatch_io(int rw, unsigned
 	 * Drop the extra refence that we were holding to avoid
 	 * the io being completed too early.
 	 */
-	dec_count(io, 0, 0);
+	dec_count(io, 0, BLK_SUCCESS);
 }
 
 static int sync_io(unsigned int num_regions, struct io_region *where,
diff --git a/drivers/md/dm-zero.c b/drivers/md/dm-zero.c
--- a/drivers/md/dm-zero.c
+++ b/drivers/md/dm-zero.c
@@ -41,7 +41,7 @@ static int zero_map(struct dm_target *ti
 		break;
 	}
 
-	bio_endio(bio, bio->bi_size, 0);
+	bio_endio(bio, bio->bi_size, BLK_SUCCESS);
 
 	/* accepted bio, don't make new request */
 	return 0;
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -294,8 +294,25 @@ struct dm_table *dm_get_table(struct map
  */
 static inline void dec_pending(struct dm_io *io, int error)
 {
-	if (error)
-		io->error = error;
+	/*
+	 * When called from the endio functions io->error will
+	 * have been set or we will be passed a BLKERR value.
+	 * If this is called from the mapping functions then will get
+	 * a old error value because we have not converted them yet
+	 */
+	if (error && io->error == BLK_SUCCESS) {
+		switch (error) {
+			case -EWOULDBLOCK:
+				io->error = BLKERR_WOULDBLOCK;
+				break;
+			case -EOPNOTSUPP:
+				io->error = BLKERR_NOTSUPP;
+				break;
+			default:
+				io->error = BLKERR_IO;
+				break;
+		}
+	}
 
 	if (atomic_dec_and_test(&io->io_count)) {
 		if (atomic_dec_and_test(&io->md->pending))
@@ -317,19 +334,22 @@ static int clone_endio(struct bio *bio, 
 	if (bio->bi_size)
 		return 1;
 
-	if (!bio_flagged(bio, BIO_UPTODATE) && !error)
-		error = -EIO;
+	if (!bio_flagged(bio, BIO_UPTODATE) && error == BLK_SUCCESS)
+		error = BLKERR_IO;
 
 	if (endio) {
 		r = endio(tio->ti, bio, error, &tio->info);
-		if (r < 0)
+		if (r >= 0)
 			error = r;
 
-		else if (r > 0)
+		else if (r < 0)
 			/* the target wants another shot at the io */
 			return 1;
 	}
 
+	if (error != BLK_SUCCESS)
+		io->error = error;
+
 	free_tio(io->md, tio);
 	dec_pending(io, error);
 	bio_put(bio);
@@ -539,7 +559,7 @@ static void __split_bio(struct mapped_de
 	ci.md = md;
 	ci.bio = bio;
 	ci.io = alloc_io(md);
-	ci.io->error = 0;
+	ci.io->error = BLK_SUCCESS;
 	atomic_set(&ci.io->io_count, 1);
 	ci.io->bio = bio;
 	ci.io->md = md;
@@ -552,7 +572,7 @@ static void __split_bio(struct mapped_de
 		__clone_and_map(&ci);
 
 	/* drop the extra reference count */
-	dec_pending(ci.io, 0);
+	dec_pending(ci.io, BLK_SUCCESS);
 	dm_table_put(ci.map);
 }
 /*-----------------------------------------------------------------