erofs: use credential guards

Use credential guards for scoped credential override with automatic
restoration on scope exit.

Link: https://patch.msgid.link/20251103-work-creds-guards-simple-v1-9-a3e156839e7f@kernel.org
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>

diff --git a/fs/erofs/fileio.c b/fs/erofs/fileio.c
index b7b3432a9882e0e0e8912e6b126405eb12204547..d27938435b2f8c6b7c9667e0242357e8d9e0a637 100644 (file)
--- a/fs/erofs/fileio.c
+++ b/fs/erofs/fileio.c
@@ -47,7 +47,6 @@ static void erofs_fileio_ki_complete(struct kiocb *iocb, long ret)
 
 static void erofs_fileio_rq_submit(struct erofs_fileio_rq *rq)
 {
-       const struct cred *old_cred;
        struct iov_iter iter;
        int ret;
 
@@ -61,9 +60,8 @@ static void erofs_fileio_rq_submit(struct erofs_fileio_rq *rq)
                rq->iocb.ki_flags = IOCB_DIRECT;
        iov_iter_bvec(&iter, ITER_DEST, rq->bvecs, rq->bio.bi_vcnt,
                      rq->bio.bi_iter.bi_size);
-       old_cred = override_creds(rq->iocb.ki_filp->f_cred);
-       ret = vfs_iocb_iter_read(rq->iocb.ki_filp, &rq->iocb, &iter);
-       revert_creds(old_cred);
+       scoped_with_creds(rq->iocb.ki_filp->f_cred)
+               ret = vfs_iocb_iter_read(rq->iocb.ki_filp, &rq->iocb, &iter);
        if (ret != -EIOCBQUEUED)
                erofs_fileio_ki_complete(&rq->iocb, ret);
 }