From 399c9bdbd6500254895bdbb574a4acbb860cda41 Mon Sep 17 00:00:00 2001 From: Huaisheng Ye <yehs1@lenovo.com> Date: Tue, 15 Sep 2020 16:56:08 +0800 Subject: [PATCH] dm thin metadata: Remove unused local variable when create thin and snap The local variable disk details is not used during the creating of thin & snap devices. Remove them from dm-thin-metadata, and add pointer validity check for pointer value in btree_lookup_raw. Skip memory copy when the caller doesn't need the value. Signed-off-by: Huaisheng Ye <yehs1@lenovo.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> --- drivers/md/dm-thin-metadata.c | 6 ++---- drivers/md/persistent-data/dm-btree.c | 3 ++- 2 files changed, 4 insertions(+), 5 deletions(-) diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c index b461836b6d26..6ebb2127f3e2 100644 --- a/drivers/md/dm-thin-metadata.c +++ b/drivers/md/dm-thin-metadata.c @@ -1051,12 +1051,11 @@ static int __create_thin(struct dm_pool_metadata *pmd, int r; dm_block_t dev_root; uint64_t key = dev; - struct disk_device_details details_le; struct dm_thin_device *td; __le64 value; r = dm_btree_lookup(&pmd->details_info, pmd->details_root, - &key, &details_le); + &key, NULL); if (!r) return -EEXIST; @@ -1129,12 +1128,11 @@ static int __create_snap(struct dm_pool_metadata *pmd, dm_block_t origin_root; uint64_t key = origin, dev_key = dev; struct dm_thin_device *td; - struct disk_device_details details_le; __le64 value; /* check this device is unused */ r = dm_btree_lookup(&pmd->details_info, pmd->details_root, - &dev_key, &details_le); + &dev_key, NULL); if (!r) return -EEXIST; diff --git a/drivers/md/persistent-data/dm-btree.c b/drivers/md/persistent-data/dm-btree.c index 8aae0624a297..ef6e78d45d5b 100644 --- a/drivers/md/persistent-data/dm-btree.c +++ b/drivers/md/persistent-data/dm-btree.c @@ -366,7 +366,8 @@ static int btree_lookup_raw(struct ro_spine *s, dm_block_t block, uint64_t key, } while (!(flags & LEAF_NODE)); *result_key = le64_to_cpu(ro_node(s)->keys[i]); - memcpy(v, value_ptr(ro_node(s), i), value_size); + if (v) + memcpy(v, value_ptr(ro_node(s), i), value_size); return 0; }