Unverified Commit b5179dbd authored by Jonathan Cavitt's avatar Jonathan Cavitt Committed by Rodrigo Vivi
Browse files

drm/xe/guc: READ/WRITE_ONCE g2h_fence->done 



Use READ_ONCE and WRITE_ONCE when operating on g2h_fence->done
to prevent the compiler from ignoring important modifications
to its value.

Fixes: dd08ebf6 ("drm/xe: Introduce a new DRM driver for Intel GPUs")
Suggested-by: default avatarMatthew Brost <matthew.brost@intel.com>
Signed-off-by: default avatarJonathan Cavitt <jonathan.cavitt@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: default avatarMatthew Brost <matthew.brost@intel.com>
Link: https://patch.msgid.link/20251222201957.63245-5-jonathan.cavitt@intel.com


Signed-off-by: default avatarRodrigo Vivi <rodrigo.vivi@intel.com>
parent c3a613a0

drivers/gpu/drm/xe/xe_guc_ct.c

+10 −4
Original line number Diff line number Diff line
@@ -206,7 +206,9 @@ static void g2h_fence_cancel(struct g2h_fence *g2h_fence) 
{

	g2h_fence->cancel = true;

	g2h_fence->fail = true;

	g2h_fence->done = true;



	/* WRITE_ONCE pairs with READ_ONCEs in guc_ct_send_recv. */

	WRITE_ONCE(g2h_fence->done, true);

}



static bool g2h_fence_needs_alloc(struct g2h_fence *g2h_fence)
@@ -1294,10 +1296,13 @@ static int guc_ct_send_recv(struct xe_guc_ct *ct, const u32 *action, u32 len, 
		return ret;

	}



	ret = wait_event_timeout(ct->g2h_fence_wq, g2h_fence.done, HZ);

	/* READ_ONCEs pairs with WRITE_ONCEs in parse_g2h_response

	 * and g2h_fence_cancel.

	 */

	ret = wait_event_timeout(ct->g2h_fence_wq, READ_ONCE(g2h_fence.done), HZ);

	if (!ret) {

		LNL_FLUSH_WORK(&ct->g2h_worker);

		if (g2h_fence.done) {

		if (READ_ONCE(g2h_fence.done)) {

			xe_gt_warn(gt, "G2H fence %u, action %04x, done\n",

				   g2h_fence.seqno, action[0]);

			ret = 1;
@@ -1498,7 +1503,8 @@ static int parse_g2h_response(struct xe_guc_ct *ct, u32 *msg, u32 len) 


	g2h_release_space(ct, GUC_CTB_HXG_MSG_MAX_LEN);



	g2h_fence->done = true;

	/* WRITE_ONCE pairs with READ_ONCEs in guc_ct_send_recv. */

	WRITE_ONCE(g2h_fence->done, true);

	smp_mb();



	wake_up_all(&ct->g2h_fence_wq);