bcachefs: push rcu lock down into bch2_target_to_mask()

We have one caller that cycles the rcu lock solely for this call
(via target_rw_devs()), and we'd like to add another. Simplify
things by pushing the rcu lock down into bch2_target_to_mask(),
similar to how bch2_dev_in_target() works.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

diff --git a/fs/bcachefs/alloc_foreground.c b/fs/bcachefs/alloc_foreground.c
index ec77601ebd0cb704683514ac42b0339ae0fc1eb2..a7e6852271d2b76bb46502346525786857ec43d6 100644 (file)
--- a/fs/bcachefs/alloc_foreground.c
+++ b/fs/bcachefs/alloc_foreground.c
@@ -934,9 +934,7 @@ static int __open_bucket_add_buckets(struct btree_trans *trans,
        unsigned i;
        int ret;
 
-       rcu_read_lock();
        devs = target_rw_devs(c, wp->data_type, target);
-       rcu_read_unlock();
 
        /* Don't allocate from devices we already have pointers to: */
        for (i = 0; i < devs_have->nr; i++)

diff --git a/fs/bcachefs/disk_groups.c b/fs/bcachefs/disk_groups.c
index aa3a4e5a8b2ecea8c9845e6565df9d429a34a311..52b6400779704abad9f9f66ace56cecb9355a8ed 100644 (file)
--- a/fs/bcachefs/disk_groups.c
+++ b/fs/bcachefs/disk_groups.c
@@ -208,26 +208,36 @@ int bch2_sb_disk_groups_to_cpu(struct bch_fs *c)
 const struct bch_devs_mask *bch2_target_to_mask(struct bch_fs *c, unsigned target)
 {
        struct target t = target_decode(target);
+       struct bch_devs_mask *devs;
+
+       rcu_read_lock();
 
        switch (t.type) {
        case TARGET_NULL:
-               return NULL;
+               devs = NULL;
+               break;
        case TARGET_DEV: {
                struct bch_dev *ca = t.dev < c->sb.nr_devices
                        ? rcu_dereference(c->devs[t.dev])
                        : NULL;
-               return ca ? &ca->self : NULL;
+               devs = ca ? &ca->self : NULL;
+               break;
        }
        case TARGET_GROUP: {
                struct bch_disk_groups_cpu *g = rcu_dereference(c->disk_groups);
 
-               return g && t.group < g->nr && !g->entries[t.group].deleted
+               devs = g && t.group < g->nr && !g->entries[t.group].deleted
                        ? &g->entries[t.group].devs
                        : NULL;
+               break;
        }
        default:
                BUG();
        }
+
+       rcu_read_unlock();
+
+       return devs;
 }
 
 bool bch2_dev_in_target(struct bch_fs *c, unsigned dev, unsigned target)