Merge patch series "cred: rework {override,revert}_creds()"

Christian Brauner <brauner@kernel.org> says:

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. This series follow Linus advice and
unifies the separate helpers and simply makes {override,revert}_creds()
do what {override,revert}_creds_light() currently does. Caller's that
really need the extra reference count can take it manually.

* patches from https://lore.kernel.org/r/20241125-work-cred-v2-0-68b9d38bb5b2@kernel.org: (29 commits)
  cred: remove unused get_new_cred()
  nfsd: avoid pointless cred reference count bump
  cachefiles: avoid pointless cred reference count bump
  dns_resolver: avoid pointless cred reference count bump
  trace: avoid pointless cred reference count bump
  cgroup: avoid pointless cred reference count bump
  acct: avoid pointless reference count bump
  io_uring: avoid pointless cred reference count bump
  smb: avoid pointless cred reference count bump
  cifs: avoid pointless cred reference count bump
  cifs: avoid pointless cred reference count bump
  ovl: avoid pointless cred reference count bump
  open: avoid pointless cred reference count bump
  nfsfh: avoid pointless cred reference count bump
  nfs/nfs4recover: avoid pointless cred reference count bump
  nfs/nfs4idmap: avoid pointless reference count bump
  nfs/localio: avoid pointless cred reference count bumps
  coredump: avoid pointless cred reference count bump
  binfmt_misc: avoid pointless cred reference count bump
  aio: avoid pointless cred reference count bump
  ...

Link: https://lore.kernel.org/r/20241125-work-cred-v2-0-68b9d38bb5b2@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>

1 files changed, 10 insertions, 10 deletions

diff --git a/fs/backing-file.c b/fs/backing-file.c
index cbdad8b68474..763fbe9b72b2 100644
--- a/fs/backing-file.c
+++ b/fs/backing-file.c
@@ -176,7 +176,7 @@ ssize_t backing_file_read_iter(struct file *file, struct iov_iter *iter,
 	    !(file->f_mode & FMODE_CAN_ODIRECT))
 		return -EINVAL;
 
-	old_cred = override_creds_light(ctx->cred);
+	old_cred = override_creds(ctx->cred);
 	if (is_sync_kiocb(iocb)) {
 		rwf_t rwf = iocb_to_rw_flags(flags);
 
@@ -197,7 +197,7 @@ ssize_t backing_file_read_iter(struct file *file, struct iov_iter *iter,
 			backing_aio_cleanup(aio, ret);
 	}
 out:
-	revert_creds_light(old_cred);
+	revert_creds(old_cred);
 
 	if (ctx->accessed)
 		ctx->accessed(iocb->ki_filp);
@@ -233,7 +233,7 @@ ssize_t backing_file_write_iter(struct file *file, struct iov_iter *iter,
 	 */
 	flags &= ~IOCB_DIO_CALLER_COMP;
 
-	old_cred = override_creds_light(ctx->cred);
+	old_cred = override_creds(ctx->cred);
 	if (is_sync_kiocb(iocb)) {
 		rwf_t rwf = iocb_to_rw_flags(flags);
 
@@ -264,7 +264,7 @@ ssize_t backing_file_write_iter(struct file *file, struct iov_iter *iter,
 			backing_aio_cleanup(aio, ret);
 	}
 out:
-	revert_creds_light(old_cred);
+	revert_creds(old_cred);
 
 	return ret;
 }
@@ -281,9 +281,9 @@ ssize_t backing_file_splice_read(struct file *in, struct kiocb *iocb,
 	if (WARN_ON_ONCE(!(in->f_mode & FMODE_BACKING)))
 		return -EIO;
 
-	old_cred = override_creds_light(ctx->cred);
+	old_cred = override_creds(ctx->cred);
 	ret = vfs_splice_read(in, &iocb->ki_pos, pipe, len, flags);
-	revert_creds_light(old_cred);
+	revert_creds(old_cred);
 
 	if (ctx->accessed)
 		ctx->accessed(iocb->ki_filp);
@@ -310,11 +310,11 @@ ssize_t backing_file_splice_write(struct pipe_inode_info *pipe,
 	if (ret)
 		return ret;
 
-	old_cred = override_creds_light(ctx->cred);
+	old_cred = override_creds(ctx->cred);
 	file_start_write(out);
 	ret = out->f_op->splice_write(pipe, out, &iocb->ki_pos, len, flags);
 	file_end_write(out);
-	revert_creds_light(old_cred);
+	revert_creds(old_cred);
 
 	if (ctx->end_write)
 		ctx->end_write(iocb, ret);
@@ -338,9 +338,9 @@ int backing_file_mmap(struct file *file, struct vm_area_struct *vma,
 
 	vma_set_file(vma, file);
 
-	old_cred = override_creds_light(ctx->cred);
+	old_cred = override_creds(ctx->cred);
 	ret = call_mmap(vma->vm_file, vma);
-	revert_creds_light(old_cred);
+	revert_creds(old_cred);
 
 	if (ctx->accessed)
 		ctx->accessed(user_file);