[PATCH] dm snapshot: make read and write exception functions void

read_exception() and write_exception() only return an error if supplied with
an out-of-range index.  If this ever happens it's the result of a bug in the
calling code so we handle this with an assertion and remove the error handling
in the callers.

Signed-off-by: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 8 insertions, 24 deletions

diff --git a/drivers/md/dm-exception-store.c b/drivers/md/dm-exception-store.c
index 8b4cd02f75a8..002417da1224 100644
--- a/drivers/md/dm-exception-store.c
+++ b/drivers/md/dm-exception-store.c
@@ -296,42 +296,29 @@ static int write_header(struct pstore *ps)
  */
 static struct disk_exception *get_exception(struct pstore *ps, uint32_t index)
 {
-        if (index >= ps->exceptions_per_area)
-                return NULL;
+        BUG_ON(index >= ps->exceptions_per_area);
 
         return ((struct disk_exception *) ps->area) + index;
 }
 
-static int read_exception(struct pstore *ps,
-                          uint32_t index, struct disk_exception *result)
+static void read_exception(struct pstore *ps,
+                           uint32_t index, struct disk_exception *result)
 {
-        struct disk_exception *e;
-
-        e = get_exception(ps, index);
-        if (!e)
-                return -EINVAL;
+        struct disk_exception *e = get_exception(ps, index);
 
         /* copy it */
         result->old_chunk = le64_to_cpu(e->old_chunk);
         result->new_chunk = le64_to_cpu(e->new_chunk);
-
-        return 0;
 }
 
-static int write_exception(struct pstore *ps,
-                           uint32_t index, struct disk_exception *de)
+static void write_exception(struct pstore *ps,
+                            uint32_t index, struct disk_exception *de)
 {
-        struct disk_exception *e;
-
-        e = get_exception(ps, index);
-        if (!e)
-                return -EINVAL;
+        struct disk_exception *e = get_exception(ps, index);
 
         /* copy it */
         e->old_chunk = cpu_to_le64(de->old_chunk);
         e->new_chunk = cpu_to_le64(de->new_chunk);
-
-        return 0;
 }
 
 /*
@@ -349,10 +336,7 @@ static int insert_exceptions(struct pstore *ps, int *full)
         *full = 1;
 
         for (i = 0; i < ps->exceptions_per_area; i++) {
-                r = read_exception(ps, i, &de);
-
-                if (r)
-                        return r;
+                read_exception(ps, i, &de);
 
                 /*
                  * If the new_chunk is pointing at the start of