io_uring: encapsulate extraneous wait flags into a separate struct

Rather than need to pass in 2 or 3 separate arguments, add a struct
to encapsulate the timeout and sigset_t parts of waiting. In preparation
for adding another argument for waiting.
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring/io_uring.c

@@ -2384,13 +2384,18 @@ static inline int io_cqring_wait_schedule(struct io_ring_ctx *ctx,
 	return ret;
 }
 
+struct ext_arg {
+	size_t argsz;
+	struct __kernel_timespec __user *ts;
+	const sigset_t __user *sig;
+};
+
 /*
  * Wait until events become available, if we don't already have some. The
  * application must reap them itself, as they reside on the shared cq ring.
  */
 static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events, u32 flags,
-			  const sigset_t __user *sig, size_t sigsz,
-			  struct __kernel_timespec __user *uts)
+			  struct ext_arg *ext_arg)
 {
 	struct io_wait_queue iowq;
 	struct io_rings *rings = ctx->rings;
@@ -2415,10 +2420,10 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events, u32 flags,
 	iowq.cq_tail = READ_ONCE(ctx->rings->cq.head) + min_events;
 	iowq.timeout = KTIME_MAX;
 
-	if (uts) {
+	if (ext_arg->ts) {
 		struct timespec64 ts;
 
-		if (get_timespec64(&ts, uts))
+		if (get_timespec64(&ts, ext_arg->ts))
 			return -EFAULT;
 
 		iowq.timeout = timespec64_to_ktime(ts);
@@ -2426,14 +2431,14 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events, u32 flags,
 			iowq.timeout = ktime_add(iowq.timeout, io_get_time(ctx));
 	}
 
-	if (sig) {
+	if (ext_arg->sig) {
 #ifdef CONFIG_COMPAT
 		if (in_compat_syscall())
-			ret = set_compat_user_sigmask((const compat_sigset_t __user *)sig,
-						      sigsz);
+			ret = set_compat_user_sigmask((const compat_sigset_t __user *)ext_arg->sig,
+						      ext_arg->argsz);
 		else
 #endif
-			ret = set_user_sigmask(sig, sigsz);
+			ret = set_user_sigmask(ext_arg->sig, ext_arg->argsz);
 
 		if (ret)
 			return ret;
@@ -3112,9 +3117,8 @@ static int io_validate_ext_arg(unsigned flags, const void __user *argp, size_t a
 	return 0;
 }
 
-static int io_get_ext_arg(unsigned flags, const void __user *argp, size_t *argsz,
-			  struct __kernel_timespec __user **ts,
-			  const sigset_t __user **sig)
+static int io_get_ext_arg(unsigned flags, const void __user *argp,
+			  struct ext_arg *ext_arg)
 {
 	struct io_uring_getevents_arg arg;
 
@@ -3123,8 +3127,8 @@ static int io_get_ext_arg(unsigned flags, const void __user *argp, size_t *argsz
 	 * is just a pointer to the sigset_t.
 	 */
 	if (!(flags & IORING_ENTER_EXT_ARG)) {
-		*sig = (const sigset_t __user *) argp;
-		*ts = NULL;
+		ext_arg->sig = (const sigset_t __user *) argp;
+		ext_arg->ts = NULL;
 		return 0;
 	}
 
@@ -3132,15 +3136,15 @@ static int io_get_ext_arg(unsigned flags, const void __user *argp, size_t *argsz
 	 * EXT_ARG is set - ensure we agree on the size of it and copy in our
 	 * timespec and sigset_t pointers if good.
 	 */
-	if (*argsz != sizeof(arg))
+	if (ext_arg->argsz != sizeof(arg))
 		return -EINVAL;
 	if (copy_from_user(&arg, argp, sizeof(arg)))
 		return -EFAULT;
 	if (arg.pad)
 		return -EINVAL;
-	*sig = u64_to_user_ptr(arg.sigmask);
-	*argsz = arg.sigmask_sz;
-	*ts = u64_to_user_ptr(arg.ts);
+	ext_arg->sig = u64_to_user_ptr(arg.sigmask);
+	ext_arg->argsz = arg.sigmask_sz;
+	ext_arg->ts = u64_to_user_ptr(arg.ts);
 	return 0;
 }
 
@@ -3246,15 +3250,14 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,
 			}
 			mutex_unlock(&ctx->uring_lock);
 		} else {
-			const sigset_t __user *sig;
-			struct __kernel_timespec __user *ts;
+			struct ext_arg ext_arg = { .argsz = argsz };
 
-			ret2 = io_get_ext_arg(flags, argp, &argsz, &ts, &sig);
+			ret2 = io_get_ext_arg(flags, argp, &ext_arg);
 			if (likely(!ret2)) {
 				min_complete = min(min_complete,
 						   ctx->cq_entries);
 				ret2 = io_cqring_wait(ctx, min_complete, flags,
-						      sig, argsz, ts);
+						      &ext_arg);
 			}
 		}