io_uring: simplify io_remove_personalities()

mainline inclusion
from mainline-v5.12-rc1
commit 0bead8cd
category: bugfix
bugzilla: 50492
CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=0bead8cd39b9c9c7c4e902018ccf129107ac50ef

---------------------------

The function io_remove_personalities() is very similar to
io_unregister_personality(),so implement io_remove_personalities()
calling io_unregister_personality().
Signed-off-by: NYejune Deng <yejune.deng@gmail.com>
Reviewed-by: NPavel Begunkov <asml.silence@gmail.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: Nyangerkun <yangerkun@huawei.com>
Reviewed-by: Nzhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

fs/io_uring.c

@@ -8482,9 +8482,8 @@ static int io_uring_fasync(int fd, struct file *file, int on)
 	return fasync_helper(fd, file, on, &ctx->cq_fasync);
 }
 
-static int io_remove_personalities(int id, void *p, void *data)
+static int io_unregister_personality(struct io_ring_ctx *ctx, unsigned id)
 {
-	struct io_ring_ctx *ctx = data;
 	struct io_identity *iod;
 
 	iod = idr_remove(&ctx->personality_idr, id);
@@ -8492,7 +8491,17 @@ static int io_remove_personalities(int id, void *p, void *data)
 		put_cred(iod->creds);
 		if (refcount_dec_and_test(&iod->count))
 			kfree(iod);
+		return 0;
 	}
+
+	return -EINVAL;
+}
+
+static int io_remove_personalities(int id, void *p, void *data)
+{
+	struct io_ring_ctx *ctx = data;
+
+	io_unregister_personality(ctx, id);
 	return 0;
 }
 
@@ -9583,21 +9592,6 @@ static int io_register_personality(struct io_ring_ctx *ctx)
 	return ret;
 }
 
-static int io_unregister_personality(struct io_ring_ctx *ctx, unsigned id)
-{
-	struct io_identity *iod;
-
-	iod = idr_remove(&ctx->personality_idr, id);
-	if (iod) {
-		put_cred(iod->creds);
-		if (refcount_dec_and_test(&iod->count))
-			kfree(iod);
-		return 0;
-	}
-
-	return -EINVAL;
-}
-
 static int io_register_restrictions(struct io_ring_ctx *ctx, void __user *arg,
 				    unsigned int nr_args)
 {