linux-kernel - [PATCH 2/2] platform/chrome: free ishtp buffer before sending event

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Message-Id: <20200408181638.184559-2-mathewk@chromium.org>
Date:   Wed,  8 Apr 2020 12:16:38 -0600
From:   Mathew King <mathewk@...omium.org>
To:     linux-kernel@...r.kernel.org
Cc:     Jett Rink <jettrink@...omium.org>,
        Benson Leung <bleung@...omium.org>,
        Enric Balletbo i Serra <enric.balletbo@...labora.com>,
        Guenter Roeck <groeck@...omium.org>,
        Mathew King <mathewk@...omium.org>
Subject: [PATCH 2/2] platform/chrome: free ishtp buffer before sending event

From: Jett Rink <jettrink@...omium.org>

Free the buffer as soon as we can to ensure we are using the least
amount of buffers as possible.

Signed-off-by: Jett Rink <jettrink@...omium.org>
Signed-off-by: Mathew King <mathewk@...omium.org>
---
 drivers/platform/chrome/cros_ec_ishtp.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/platform/chrome/cros_ec_ishtp.c b/drivers/platform/chrome/cros_ec_ishtp.c
index 6f90deb5cf55..7d27850b9235 100644
--- a/drivers/platform/chrome/cros_ec_ishtp.c
+++ b/drivers/platform/chrome/cros_ec_ishtp.c
@@ -303,6 +303,10 @@ static void process_recv(struct ishtp_cl *cros_ish_cl,
 		       rb_in_proc->buffer.data, data_len);
 
 error_wake_up:
+		/* Free the buffer since we copied data or didn't need it */
+		ishtp_cl_io_rb_recycle(rb_in_proc);
+		rb_in_proc = NULL;
+
 		/* Set flag before waking up the caller */
 		client_data->response.received = true;
 
@@ -312,12 +316,14 @@ static void process_recv(struct ishtp_cl *cros_ish_cl,
 		break;
 
 	case CROS_MKBP_EVENT:
+		/* Free the buffer. This is just an event without data */
+		ishtp_cl_io_rb_recycle(rb_in_proc);
+		rb_in_proc = NULL;
 		/*
 		 * Set timestamp from beginning of function since we actually
 		 * got an incoming MKBP event
 		 */
 		client_data->ec_dev->last_event_time = timestamp;
-		/* The event system doesn't send any data in buffer */
 		schedule_work(&client_data->work_ec_evt);
 
 		break;
@@ -327,8 +333,9 @@ static void process_recv(struct ishtp_cl *cros_ish_cl,
 	}
 
 end_error:
-	/* Free the buffer */
-	ishtp_cl_io_rb_recycle(rb_in_proc);
+	/* Free the buffer if we already haven't */
+	if (rb_in_proc)
+		ishtp_cl_io_rb_recycle(rb_in_proc);
 
 	up_read(&init_lock);
 }
-- 
2.26.0.292.g33ef6b2f38-goog