011f2c26f1
As usual these patches were extracted and rebased from the raspberry pi repo: https://github.com/raspberrypi/linux/tree/rpi-4.4.y Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
63 lines
2.2 KiB
Diff
63 lines
2.2 KiB
Diff
From 249ccc9a345b7641aaf276867a375cd50f41627d Mon Sep 17 00:00:00 2001
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From: Phil Elwell <phil@raspberrypi.org>
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Date: Thu, 21 Apr 2016 13:49:32 +0100
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Subject: [PATCH] vchiq_arm: Add completion records under the mutex
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An issue was observed when flushing openmax components
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which generate a large number of messages returning
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buffers to host.
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We occasionally found a duplicate message from 16
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messages prior, resulting in a buffer returned twice.
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While only one thread adds completions, without the
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mutex you don't get the protection of the automatic
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memory barrier you get with synchronisation objects.
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Signed-off-by: Phil Elwell <phil@raspberrypi.org>
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---
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drivers/misc/vc04_services/interface/vchiq_arm/vchiq_arm.c | 13 ++++++++++++-
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1 file changed, 12 insertions(+), 1 deletion(-)
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--- a/drivers/misc/vc04_services/interface/vchiq_arm/vchiq_arm.c
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+++ b/drivers/misc/vc04_services/interface/vchiq_arm/vchiq_arm.c
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@@ -210,6 +210,8 @@ add_completion(VCHIQ_INSTANCE_T instance
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VCHIQ_COMPLETION_DATA_T *completion;
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DEBUG_INITIALISE(g_state.local)
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+ mutex_lock(&instance->completion_mutex);
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+
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while (instance->completion_insert ==
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(instance->completion_remove + MAX_COMPLETIONS)) {
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/* Out of space - wait for the client */
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@@ -217,11 +219,17 @@ add_completion(VCHIQ_INSTANCE_T instance
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vchiq_log_trace(vchiq_arm_log_level,
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"add_completion - completion queue full");
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DEBUG_COUNT(COMPLETION_QUEUE_FULL_COUNT);
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+
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+ mutex_unlock(&instance->completion_mutex);
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if (down_interruptible(&instance->remove_event) != 0) {
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vchiq_log_info(vchiq_arm_log_level,
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"service_callback interrupted");
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return VCHIQ_RETRY;
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- } else if (instance->closing) {
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+ }
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+
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+ mutex_lock(&instance->completion_mutex);
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+ if (instance->closing) {
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+ mutex_unlock(&instance->completion_mutex);
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vchiq_log_info(vchiq_arm_log_level,
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"service_callback closing");
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return VCHIQ_SUCCESS;
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@@ -254,8 +262,11 @@ add_completion(VCHIQ_INSTANCE_T instance
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if (reason == VCHIQ_MESSAGE_AVAILABLE)
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user_service->message_available_pos =
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instance->completion_insert;
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+
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instance->completion_insert++;
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+ mutex_unlock(&instance->completion_mutex);
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+
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up(&instance->insert_event);
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return VCHIQ_SUCCESS;
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