io_uring: Factor out a function to parse restrictions

Preparation for subsequent work on inherited restrictions.

Signed-off-by: Josh Triplett <[email protected]>
Reviewed-by: Pavel Begunkov <[email protected]>
Link: https://lore.kernel.org/r/9bac2b4d1b9b9ab41c55ea3816021be847f354df.1736932318.git.josh@joshtriplett.org
Signed-off-by: Jens Axboe <[email protected]>

Author: joshtriplett

io_uring/register.c

@@ -104,21 +104,13 @@ static int io_register_personality(struct io_ring_ctx *ctx)
 	return id;
 }
 
-static __cold int io_register_restrictions(struct io_ring_ctx *ctx,
-					   void __user *arg, unsigned int nr_args)
+static __cold int io_parse_restrictions(void __user *arg, unsigned int nr_args,
+					struct io_restriction *restrictions)
 {
 	struct io_uring_restriction *res;
 	size_t size;
 	int i, ret;
 
-	/* Restrictions allowed only if rings started disabled */
-	if (!(ctx->flags & IORING_SETUP_R_DISABLED))
-		return -EBADFD;
-
-	/* We allow only a single restrictions registration */
-	if (ctx->restrictions.registered)
-		return -EBUSY;
-
 	if (!arg || nr_args > IORING_MAX_RESTRICTIONS)
 		return -EINVAL;
 
@@ -130,47 +122,57 @@ static __cold int io_register_restrictions(struct io_ring_ctx *ctx,
 	if (IS_ERR(res))
 		return PTR_ERR(res);
 
-	ret = 0;
+	ret = -EINVAL;
 
 	for (i = 0; i < nr_args; i++) {
 		switch (res[i].opcode) {
 		case IORING_RESTRICTION_REGISTER_OP:
-			if (res[i].register_op >= IORING_REGISTER_LAST) {
-				ret = -EINVAL;
-				goto out;
-			}
-
-			__set_bit(res[i].register_op,
-				  ctx->restrictions.register_op);
+			if (res[i].register_op >= IORING_REGISTER_LAST)
+				goto err;
+			__set_bit(res[i].register_op, restrictions->register_op);
 			break;
 		case IORING_RESTRICTION_SQE_OP:
-			if (res[i].sqe_op >= IORING_OP_LAST) {
-				ret = -EINVAL;
-				goto out;
-			}
-
-			__set_bit(res[i].sqe_op, ctx->restrictions.sqe_op);
+			if (res[i].sqe_op >= IORING_OP_LAST)
+				goto err;
+			__set_bit(res[i].sqe_op, restrictions->sqe_op);
 			break;
 		case IORING_RESTRICTION_SQE_FLAGS_ALLOWED:
-			ctx->restrictions.sqe_flags_allowed = res[i].sqe_flags;
+			restrictions->sqe_flags_allowed = res[i].sqe_flags;
 			break;
 		case IORING_RESTRICTION_SQE_FLAGS_REQUIRED:
-			ctx->restrictions.sqe_flags_required = res[i].sqe_flags;
+			restrictions->sqe_flags_required = res[i].sqe_flags;
 			break;
 		default:
-			ret = -EINVAL;
-			goto out;
+			goto err;
 		}
 	}
 
-out:
+	ret = 0;
+
+err:
+	kfree(res);
+	return ret;
+}
+
+static __cold int io_register_restrictions(struct io_ring_ctx *ctx,
+					   void __user *arg, unsigned int nr_args)
+{
+	int ret;
+
+	/* Restrictions allowed only if rings started disabled */
+	if (!(ctx->flags & IORING_SETUP_R_DISABLED))
+		return -EBADFD;
+
+	/* We allow only a single restrictions registration */
+	if (ctx->restrictions.registered)
+		return -EBUSY;
+
+	ret = io_parse_restrictions(arg, nr_args, &ctx->restrictions);
 	/* Reset all restrictions if an error happened */
 	if (ret != 0)
 		memset(&ctx->restrictions, 0, sizeof(ctx->restrictions));
 	else
 		ctx->restrictions.registered = true;
-
-	kfree(res);
 	return ret;
 }