lib/igt_aux: Divert ioctls for signal injection

To simplify and speed up running interruptible tests, use a custom
ioctl() function that control the signaling and detect when we need no
more iterations to trigger an interruption.

We use a realtime timer to inject the signal after a certain delay,
increasing the delay on every loop to try and exercise different code
paths within the function. The first delay is very short such that we
hopefully enter the kernel with a pending signal.

Clients should use

struct igt_sigiter iter = {};
while (igt_sigiter_repeat(&iter, enable_interrupts=true))
	do_test()

to automatically repeat the test until we can inject no more signals
into the ioctls. This is condensed into a macro

igt_interruptible(enable_interrupts=true)
	do_test();

for convenience.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 8 insertions, 0 deletions

diff --git a/lib/igt_aux.h b/lib/igt_aux.h
index 427719ef..eabeefd2 100644
--- a/lib/igt_aux.h
+++ b/lib/igt_aux.h
@@ -40,6 +40,14 @@ extern int num_trash_bos;
 void igt_fork_signal_helper(void);
 void igt_stop_signal_helper(void);
 
+struct igt_sigiter {
+	unsigned pass;
+};
+
+bool igt_sigiter_continue(struct igt_sigiter *iter, bool interrupt);
+#define igt_interruptible(E) \
+	for (struct igt_sigiter iter__={}; igt_sigiter_continue(&iter__, (E)); )
+
 void igt_exchange_int(void *array, unsigned i, unsigned j);
 void igt_permute_array(void *array, unsigned size,
 			   void (*exchange_func)(void *array,