From 36f241fff4720f205e36bda5900d4ef7b6662bd7 Mon Sep 17 00:00:00 2001 From: Bryan O'Donoghue Date: Fri, 11 Dec 2015 13:46:52 +0000 Subject: [PATCH] greybus: loopback: Wait for all async operations to complete on exit On gb_loopback_connection_exit() we should ensure every issued asynchronous operation completes before exiting connection_exit(). This patch introduces a waitqueue with a counter which represents the number of incomplete asynchronous operations. When the counter reaches zero connection_exit() will complete. At the point which we wait for outstanding operations to complete the connection-specific loopback thread will have ceased to issue new operations. Tested with both synchronous and asynchronous operations. Reviewed-by: Johan Hovold Suggested-by: Johan Hovold Signed-off-by: Bryan O'Donoghue Signed-off-by: Greg Kroah-Hartman --- drivers/staging/greybus/loopback.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/drivers/staging/greybus/loopback.c b/drivers/staging/greybus/loopback.c index eb6a013..4814f94 100644 --- a/drivers/staging/greybus/loopback.c +++ b/drivers/staging/greybus/loopback.c @@ -21,6 +21,7 @@ #include #include #include +#include #include @@ -73,6 +74,8 @@ struct gb_loopback { struct list_head entry; struct device *dev; wait_queue_head_t wq; + wait_queue_head_t wq_completion; + atomic_t outstanding_operations; /* Per connection stats */ struct gb_loopback_stats latency; @@ -433,6 +436,8 @@ static void __gb_loopback_async_operation_destroy(struct kref *kref) list_del(&op_async->entry); if (op_async->operation) gb_operation_put(op_async->operation); + atomic_dec(&op_async->gb->outstanding_operations); + wake_up(&op_async->gb->wq_completion); kfree(op_async); } @@ -472,6 +477,12 @@ static struct gb_loopback_async_operation * return found ? op_async : NULL; } +static void gb_loopback_async_wait_all(struct gb_loopback *gb) +{ + wait_event(gb->wq_completion, + !atomic_read(&gb->outstanding_operations)); +} + static void gb_loopback_async_operation_callback(struct gb_operation *operation) { struct gb_loopback_async_operation *op_async; @@ -597,6 +608,7 @@ static int gb_loopback_async_operation(struct gb_loopback *gb, int type, do_gettimeofday(&op_async->ts); op_async->pending = true; + atomic_inc(&gb->outstanding_operations); ret = gb_operation_request_send(operation, gb_loopback_async_operation_callback, GFP_KERNEL); @@ -1063,6 +1075,8 @@ static int gb_loopback_connection_init(struct gb_connection *connection) return -ENOMEM; init_waitqueue_head(&gb->wq); + init_waitqueue_head(&gb->wq_completion); + atomic_set(&gb->outstanding_operations, 0); gb_loopback_reset_stats(gb); /* Reported values to user-space for min/max timeouts */ @@ -1162,6 +1176,7 @@ static void gb_loopback_connection_exit(struct gb_connection *connection) kfifo_free(&gb->kfifo_ts); gb_connection_latency_tag_disable(connection); debugfs_remove(gb->file); + gb_loopback_async_wait_all(gb); spin_lock_irqsave(&gb_dev.lock, flags); gb_dev.count--; -- 2.7.4