imsm: Remove possibility for get_imsm_dev to return NULL

Returning NULL from get_imsm_dev or __get_imsm_dev will cause segfault.
Guarantee that it never happens.

Signed-off-by: Mateusz Grzonka <mateusz.grzonka@intel.com>
Signed-off-by: Jes Sorensen <jsorensen@fb.com>

diff --git a/super-intel.c b/super-intel.c
index ba3bd41f793798e5173cc5ec6a5cda0bed3ccc88..3788feb9c2dafb92d983caf02e6b7a9dfc3b219a 100644 (file)
--- a/super-intel.c
+++ b/super-intel.c
@@ -851,6 +851,21 @@ static struct disk_info *get_disk_info(struct imsm_update_create_array *update)
        return inf;
 }
 
+/**
+ * __get_imsm_dev() - Get device with index from imsm_super.
+ * @mpb: &imsm_super pointer, not NULL.
+ * @index: Device index.
+ *
+ * Function works as non-NULL, aborting in such a case,
+ * when NULL would be returned.
+ *
+ * Device index should be in range 0 up to num_raid_devs.
+ * Function assumes the index was already verified.
+ * Index must be valid, otherwise abort() is called.
+ *
+ * Return: Pointer to corresponding imsm_dev.
+ *
+ */
 static struct imsm_dev *__get_imsm_dev(struct imsm_super *mpb, __u8 index)
 {
        int offset;
@@ -858,30 +873,47 @@ static struct imsm_dev *__get_imsm_dev(struct imsm_super *mpb, __u8 index)
        void *_mpb = mpb;
 
        if (index >= mpb->num_raid_devs)
-               return NULL;
+               goto error;
 
        /* devices start after all disks */
        offset = ((void *) &mpb->disk[mpb->num_disks]) - _mpb;
 
-       for (i = 0; i <= index; i++)
+       for (i = 0; i <= index; i++, offset += sizeof_imsm_dev(_mpb + offset, 0))
                if (i == index)
                        return _mpb + offset;
-               else
-                       offset += sizeof_imsm_dev(_mpb + offset, 0);
-
-       return NULL;
+error:
+       pr_err("cannot find imsm_dev with index %u in imsm_super\n", index);
+       abort();
 }
 
+/**
+ * get_imsm_dev() - Get device with index from intel_super.
+ * @super: &intel_super pointer, not NULL.
+ * @index: Device index.
+ *
+ * Function works as non-NULL, aborting in such a case,
+ * when NULL would be returned.
+ *
+ * Device index should be in range 0 up to num_raid_devs.
+ * Function assumes the index was already verified.
+ * Index must be valid, otherwise abort() is called.
+ *
+ * Return: Pointer to corresponding imsm_dev.
+ *
+ */
 static struct imsm_dev *get_imsm_dev(struct intel_super *super, __u8 index)
 {
        struct intel_dev *dv;
 
        if (index >= super->anchor->num_raid_devs)
-               return NULL;
+               goto error;
+
        for (dv = super->devlist; dv; dv = dv->next)
                if (dv->index == index)
                        return dv->dev;
-       return NULL;
+error:
+       pr_err("cannot find imsm_dev with index %u in intel_super\n", index);
+       abort();
 }
 
 static inline unsigned long long __le48_to_cpu(const struct bbm_log_block_addr
@@ -4364,8 +4396,7 @@ int check_mpb_migr_compatibility(struct intel_super *super)
        for (i = 0; i < super->anchor->num_raid_devs; i++) {
                struct imsm_dev *dev_iter = __get_imsm_dev(super->anchor, i);
 
-               if (dev_iter &&
-                   dev_iter->vol.migr_state == 1 &&
+               if (dev_iter->vol.migr_state == 1 &&
                    dev_iter->vol.migr_type == MIGR_GEN_MIGR) {
                        /* This device is migrating */
                        map0 = get_imsm_map(dev_iter, MAP_0);
@@ -4514,8 +4545,6 @@ static void clear_hi(struct intel_super *super)
        }
        for (i = 0; i < mpb->num_raid_devs; ++i) {
                struct imsm_dev *dev = get_imsm_dev(super, i);
-               if (!dev)
-                       return;
                for (n = 0; n < 2; ++n) {
                        struct imsm_map *map = get_imsm_map(dev, n);
                        if (!map)
@@ -5836,7 +5865,7 @@ static int add_to_super_imsm_volume(struct supertype *st, mdu_disk_info_t *dk,
                struct imsm_dev *_dev = __get_imsm_dev(mpb, 0);
 
                _disk = __get_imsm_disk(mpb, dl->index);
-               if (!_dev || !_disk) {
+               if (!_disk) {
                        pr_err("BUG mpb setup error\n");
                        return 1;
                }
@@ -6171,10 +6200,10 @@ static int write_super_imsm(struct supertype *st, int doclose)
        for (i = 0; i < mpb->num_raid_devs; i++) {
                struct imsm_dev *dev = __get_imsm_dev(mpb, i);
                struct imsm_dev *dev2 = get_imsm_dev(super, i);
-               if (dev && dev2) {
-                       imsm_copy_dev(dev, dev2);
-                       mpb_size += sizeof_imsm_dev(dev, 0);
-               }
+
+               imsm_copy_dev(dev, dev2);
+               mpb_size += sizeof_imsm_dev(dev, 0);
+
                if (is_gen_migration(dev2))
                        clear_migration_record = 0;
        }
@@ -9033,29 +9062,26 @@ static int imsm_rebuild_allowed(struct supertype *cont, int dev_idx, int failed)
        __u8 state;
 
        dev2 = get_imsm_dev(cont->sb, dev_idx);
-       if (dev2) {
-               state = imsm_check_degraded(cont->sb, dev2, failed, MAP_0);
-               if (state == IMSM_T_STATE_FAILED) {
-                       map = get_imsm_map(dev2, MAP_0);
-                       if (!map)
-                               return 1;
-                       for (slot = 0; slot < map->num_members; slot++) {
-                               /*
-                                * Check if failed disks are deleted from intel
-                                * disk list or are marked to be deleted
-                                */
-                               idx = get_imsm_disk_idx(dev2, slot, MAP_X);
-                               idisk = get_imsm_dl_disk(cont->sb, idx);
-                               /*
-                                * Do not rebuild the array if failed disks
-                                * from failed sub-array are not removed from
-                                * container.
-                                */
-                               if (idisk &&
-                                   is_failed(&idisk->disk) &&
-                                   (idisk->action != DISK_REMOVE))
-                                       return 0;
-                       }
+
+       state = imsm_check_degraded(cont->sb, dev2, failed, MAP_0);
+       if (state == IMSM_T_STATE_FAILED) {
+               map = get_imsm_map(dev2, MAP_0);
+               for (slot = 0; slot < map->num_members; slot++) {
+                       /*
+                        * Check if failed disks are deleted from intel
+                        * disk list or are marked to be deleted
+                        */
+                       idx = get_imsm_disk_idx(dev2, slot, MAP_X);
+                       idisk = get_imsm_dl_disk(cont->sb, idx);
+                       /*
+                        * Do not rebuild the array if failed disks
+                        * from failed sub-array are not removed from
+                        * container.
+                        */
+                       if (idisk &&
+                           is_failed(&idisk->disk) &&
+                           (idisk->action != DISK_REMOVE))
+                               return 0;
                }
        }
        return 1;
@@ -10089,7 +10115,6 @@ static void imsm_process_update(struct supertype *st,
                int victim = u->dev_idx;
                struct active_array *a;
                struct intel_dev **dp;
-               struct imsm_dev *dev;
 
                /* sanity check that we are not affecting the uuid of
                 * active arrays, or deleting an active array
@@ -10105,8 +10130,7 @@ static void imsm_process_update(struct supertype *st,
                 * is active in the container, so checking
                 * mpb->num_raid_devs is just extra paranoia
                 */
-               dev = get_imsm_dev(super, victim);
-               if (a || !dev || mpb->num_raid_devs == 1) {
+               if (a || mpb->num_raid_devs == 1 || victim >= super->anchor->num_raid_devs) {
                        dprintf("failed to delete subarray-%d\n", victim);
                        break;
                }
@@ -10140,7 +10164,7 @@ static void imsm_process_update(struct supertype *st,
                        if (a->info.container_member == target)
                                break;
                dev = get_imsm_dev(super, u->dev_idx);
-               if (a || !dev || !check_name(super, name, 1)) {
+               if (a || !check_name(super, name, 1)) {
                        dprintf("failed to rename subarray-%d\n", target);
                        break;
                }
@@ -10169,10 +10193,6 @@ static void imsm_process_update(struct supertype *st,
                struct imsm_update_rwh_policy *u = (void *)update->buf;
                int target = u->dev_idx;
                struct imsm_dev *dev = get_imsm_dev(super, target);
-               if (!dev) {
-                       dprintf("could not find subarray-%d\n", target);
-                       break;
-               }
 
                if (dev->rwh_policy != u->new_policy) {
                        dev->rwh_policy = u->new_policy;
@@ -11397,8 +11417,10 @@ static int imsm_create_metadata_update_for_migration(
 {
        struct intel_super *super = st->sb;
        int update_memory_size;
+       int current_chunk_size;
        struct imsm_update_reshape_migration *u;
-       struct imsm_dev *dev;
+       struct imsm_dev *dev = get_imsm_dev(super, super->current_vol);
+       struct imsm_map *map = get_imsm_map(dev, MAP_0);
        int previous_level = -1;
 
        dprintf("(enter) New Level = %i\n", geo->level);
@@ -11415,23 +11437,15 @@ static int imsm_create_metadata_update_for_migration(
        u->new_disks[0] = -1;
        u->new_chunksize = -1;
 
-       dev = get_imsm_dev(super, u->subdev);
-       if (dev) {
-               struct imsm_map *map;
+       current_chunk_size = __le16_to_cpu(map->blocks_per_strip) / 2;
 
-               map = get_imsm_map(dev, MAP_0);
-               if (map) {
-                       int current_chunk_size =
-                               __le16_to_cpu(map->blocks_per_strip) / 2;
-
-                       if (geo->chunksize != current_chunk_size) {
-                               u->new_chunksize = geo->chunksize / 1024;
-                               dprintf("imsm: chunk size change from %i to %i\n",
-                                       current_chunk_size, u->new_chunksize);
-                       }
-                       previous_level = map->raid_level;
-               }
+       if (geo->chunksize != current_chunk_size) {
+               u->new_chunksize = geo->chunksize / 1024;
+               dprintf("imsm: chunk size change from %i to %i\n",
+                       current_chunk_size, u->new_chunksize);
        }
+       previous_level = map->raid_level;
+
        if (geo->level == 5 && previous_level == 0) {
                struct mdinfo *spares = NULL;
 
@@ -12519,9 +12533,6 @@ static int validate_internal_bitmap_imsm(struct supertype *st)
        unsigned long long offset;
        struct dl *d;
 
-       if (!dev)
-               return -1;
-
        if (dev->rwh_policy != RWH_BITMAP)
                return 0;
 
@@ -12567,16 +12578,8 @@ static int add_internal_bitmap_imsm(struct supertype *st, int *chunkp,
                return -1;
 
        dev = get_imsm_dev(super, vol_idx);
-
-       if (!dev) {
-               dprintf("cannot find the device for volume index %d\n",
-                       vol_idx);
-               return -1;
-       }
        dev->rwh_policy = RWH_BITMAP;
-
        *chunkp = calculate_bitmap_chunksize(st, dev);
-
        return 0;
 }