[PATCH 00/26] cred: rework {override,revert}_creds()

[Christian Brauner <brauner@kernel.org>]

For the v6.13 cycle we switched overlayfs to a variant of
override_creds() that doesn't take an extra reference. To this end I
suggested introducing {override,revert}_creds_light() which overlayfs
could use.

This seems to work rather well. As Linus correctly points out that we
should look into unifying both and simply make {override,revert}_creds()
do what {override,revert}_creds_light() currently does. Caller's that
really need the extra reference count can take it manually.

This series does all that. Afaict, most callers can be directly
converted over and can avoid the extra reference count completely.

Lightly tested.

---
Christian Brauner (26):
      tree-wide: s/override_creds()/override_creds_light(get_new_cred())/g
      cred: return old creds from revert_creds_light()
      tree-wide: s/revert_creds()/put_cred(revert_creds_light())/g
      cred: remove old {override,revert}_creds() helpers
      tree-wide: s/override_creds_light()/override_creds()/g
      tree-wide: s/revert_creds_light()/revert_creds()/g
      firmware: avoid pointless reference count bump
      sev-dev: avoid pointless cred reference count bump
      target_core_configfs: avoid pointless cred reference count bump
      aio: avoid pointless cred reference count bump
      binfmt_misc: avoid pointless cred reference count bump
      coredump: avoid pointless cred reference count bump
      nfs/localio: avoid pointless cred reference count bumps
      nfs/nfs4idmap: avoid pointless reference count bump
      nfs/nfs4recover: avoid pointless cred reference count bump
      nfsfh: avoid pointless cred reference count bump
      open: avoid pointless cred reference count bump
      ovl: avoid pointless cred reference count bump
      cifs: avoid pointless cred reference count bump
      cifs: avoid pointless cred reference count bump
      smb: avoid pointless cred reference count bump
      io_uring: avoid pointless cred reference count bump
      acct: avoid pointless reference count bump
      cgroup: avoid pointless cred reference count bump
      trace: avoid pointless cred reference count bump
      dns_resolver: avoid pointless cred reference count bump

 drivers/base/firmware_loader/main.c   |  3 +--
 drivers/crypto/ccp/sev-dev.c          |  2 +-
 drivers/target/target_core_configfs.c |  3 +--
 fs/aio.c                              |  3 +--
 fs/backing-file.c                     | 20 +++++++-------
 fs/cachefiles/internal.h              |  4 +--
 fs/nfsd/auth.c                        |  4 +--
 fs/nfsd/filecache.c                   |  2 +-
 fs/nfsd/nfs4recover.c                 |  3 +--
 fs/nfsd/nfsfh.c                       |  1 -
 fs/open.c                             | 10 ++-----
 fs/overlayfs/copy_up.c                |  6 ++---
 fs/overlayfs/dir.c                    |  4 +--
 fs/overlayfs/util.c                   |  4 +--
 fs/smb/server/smb_common.c            |  4 +--
 include/linux/cred.h                  | 14 ++++------
 kernel/cred.c                         | 50 -----------------------------------
 kernel/trace/trace_events_user.c      |  3 +--
 18 files changed, 35 insertions(+), 105 deletions(-)
---
base-commit: 228a1157fb9fec47eb135b51c0202b574e079ebf
change-id: 20241124-work-cred-349b65450082