Commit 47327fdd authored by Stephen Boyd's avatar Stephen Boyd Committed by Rob Clark
Browse files

drm/msm/dp: Shrink locking area of dp_aux_transfer() 



We don't need to hold the lock to inspect the message we're going to
transfer, and we don't need to clear the busy flag either. Take the lock
later and bail out earlier if conditions aren't met.

Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc: Abhinav Kumar <abhinavk@codeaurora.org>
Cc: Kuogee Hsieh <khsieh@codeaurora.org>
Cc: aravindh@codeaurora.org
Cc: Sean Paul <sean@poorly.run>
Signed-off-by: default avatarStephen Boyd <swboyd@chromium.org>
Reviewed-by: default avatarKuogee Hsieh <khsieh@codeaurora.org>
Link: https://lore.kernel.org/r/20210507212505.1224111-3-swboyd@chromium.org


Signed-off-by: default avatarRob Clark <robdclark@chromium.org>
parent 24c7861b

drivers/gpu/drm/msm/dp/dp_aux.c

+9 −10
Original line number Diff line number Diff line
@@ -329,30 +329,29 @@ static ssize_t dp_aux_transfer(struct drm_dp_aux *dp_aux, 
	ssize_t ret;

	int const aux_cmd_native_max = 16;

	int const aux_cmd_i2c_max = 128;

	struct dp_aux_private *aux = container_of(dp_aux,

		struct dp_aux_private, dp_aux);

	struct dp_aux_private *aux;



	mutex_lock(&aux->mutex);

	aux = container_of(dp_aux, struct dp_aux_private, dp_aux);



	aux->native = msg->request & (DP_AUX_NATIVE_WRITE & DP_AUX_NATIVE_READ);



	/* Ignore address only message */

	if ((msg->size == 0) || (msg->buffer == NULL)) {

	if (msg->size == 0 || !msg->buffer) {

		msg->reply = aux->native ?

			DP_AUX_NATIVE_REPLY_ACK : DP_AUX_I2C_REPLY_ACK;

		ret = msg->size;

		goto unlock_exit;

		return msg->size;

	}



	/* msg sanity check */

	if ((aux->native && (msg->size > aux_cmd_native_max)) ||

		(msg->size > aux_cmd_i2c_max)) {

	if ((aux->native && msg->size > aux_cmd_native_max) ||

	    msg->size > aux_cmd_i2c_max) {

		DRM_ERROR("%s: invalid msg: size(%zu), request(%x)\n",

			__func__, msg->size, msg->request);

		ret = -EINVAL;

		goto unlock_exit;

		return -EINVAL;

	}



	mutex_lock(&aux->mutex);



	dp_aux_update_offset_and_segment(aux, msg);

	dp_aux_transfer_helper(aux, msg, true);