dm raid1: dont use map_context

Don't use map_info any more in dm-raid1.

map_info was used for writes to hold the region number. For this purpose
we add a new field dm_bio_details to dm_raid1_bio_record.

map_info was used for reads to hold a pointer to dm_raid1_bio_record (if
the pointer was non-NULL, bio details were saved; if the pointer was
NULL, bio details were not saved). We use
dm_raid1_bio_record.details->bi_bdev for this purpose. If bi_bdev is
NULL, details were not saved, if bi_bdev is non-NULL, details were
saved.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

1 files changed, 13 insertions, 9 deletions

diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c
index a7d0d8a4bbdf..57685cf0afa8 100644
--- a/drivers/md/dm-raid1.c
+++ b/drivers/md/dm-raid1.c
@@ -140,7 +140,9 @@ static void dispatch_bios(void *context, struct bio_list *bio_list)
 
 struct dm_raid1_bio_record {
         struct mirror *m;
+        /* if details->bi_bdev == NULL, details were not saved */
         struct dm_bio_details details;
+        region_t write_region;
 };
 
 /*
@@ -1146,12 +1148,15 @@ static int mirror_map(struct dm_target *ti, struct bio *bio,
         int r, rw = bio_rw(bio);
         struct mirror *m;
         struct mirror_set *ms = ti->private;
-        struct dm_raid1_bio_record *bio_record;
         struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
+        struct dm_raid1_bio_record *bio_record =
+          dm_per_bio_data(bio, sizeof(struct dm_raid1_bio_record));
+
+        bio_record->details.bi_bdev = NULL;
 
         if (rw == WRITE) {
                 /* Save region for mirror_end_io() handler */
-                map_context->ll = dm_rh_bio_to_region(ms->rh, bio);
+                bio_record->write_region = dm_rh_bio_to_region(ms->rh, bio);
                 queue_bio(ms, bio, rw);
                 return DM_MAPIO_SUBMITTED;
         }
@@ -1179,9 +1184,7 @@ static int mirror_map(struct dm_target *ti, struct bio *bio,
         if (unlikely(!m))
                 return -EIO;
 
-        bio_record = dm_per_bio_data(bio, sizeof(struct dm_raid1_bio_record));
         dm_bio_record(&bio_record->details, bio);
-        map_context->ptr = bio_record;
         bio_record->m = m;
 
         map_bio(m, bio);
@@ -1196,14 +1199,15 @@ static int mirror_end_io(struct dm_target *ti, struct bio *bio,
         struct mirror_set *ms = (struct mirror_set *) ti->private;
         struct mirror *m = NULL;
         struct dm_bio_details *bd = NULL;
-        struct dm_raid1_bio_record *bio_record = map_context->ptr;
+        struct dm_raid1_bio_record *bio_record =
+          dm_per_bio_data(bio, sizeof(struct dm_raid1_bio_record));
 
         /*
          * We need to dec pending if this was a write.
          */
         if (rw == WRITE) {
                 if (!(bio->bi_rw & (REQ_FLUSH | REQ_DISCARD)))
-                        dm_rh_dec(ms->rh, map_context->ll);
+                        dm_rh_dec(ms->rh, bio_record->write_region);
                 return error;
         }
 
@@ -1214,7 +1218,7 @@ static int mirror_end_io(struct dm_target *ti, struct bio *bio,
                 goto out;
 
         if (unlikely(error)) {
-                if (!bio_record) {
+                if (!bio_record->details.bi_bdev) {
                         /*
                          * There wasn't enough memory to record necessary
                          * information for a retry or there was no other
@@ -1239,7 +1243,7 @@ static int mirror_end_io(struct dm_target *ti, struct bio *bio,
                         bd = &bio_record->details;
 
                         dm_bio_restore(bd, bio);
-                        map_context->ptr = NULL;
+                        bio_record->details.bi_bdev = NULL;
                         queue_bio(ms, bio, rw);
                         return DM_ENDIO_INCOMPLETE;
                 }
@@ -1247,7 +1251,7 @@ static int mirror_end_io(struct dm_target *ti, struct bio *bio,
         }
 
 out:
-        map_context->ptr = NULL;
+        bio_record->details.bi_bdev = NULL;
 
         return error;
 }