linux-kernel - [PATCH v3 2/3] staging: r8188eu: Use completions for signaling enqueueing

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Date:   Mon, 18 Oct 2021 18:20:05 +0200
From:   "Fabio M. De Francesco" <fmdefrancesco@...il.com>
To:     Larry Finger <Larry.Finger@...inger.net>,
        Phillip Potter <phil@...lpotter.co.uk>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Dan Carpenter <dan.carpenter@...cle.com>,
        Martin Kaiser <martin@...ser.cx>,
        linux-staging@...ts.linux.dev, linux-kernel@...r.kernel.org
Cc:     "Fabio M. De Francesco" <fmdefrancesco@...il.com>
Subject: [PATCH v3 2/3] staging: r8188eu: Use completions for signaling enqueueing

rtw_enqueue_cmd() uses a semaphore to notify rtw_cmd_thread() that it
has enqueued commands. rtw_cmd_thread() "down(s)" in interruptible mode
to wait to be notified.

Use completion variables because they are better suited for the purpose.

In rtw_cmd_thread(), wait in uninterruptible mode, even if the original
code uses down_interruptible(), because the interruption of
rtw_cmd_thread() is not allowed and unwanted.

Tested with "ASUSTek Computer, Inc. Realtek 8188EUS [USB-N10 Nano]".

Acked-by: Phillip Potter <phil@...lpotter.co.uk>
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@...il.com>
---
 drivers/staging/r8188eu/core/rtw_cmd.c    | 7 +++----
 drivers/staging/r8188eu/include/rtw_cmd.h | 2 +-
 drivers/staging/r8188eu/os_dep/os_intfs.c | 2 +-
 3 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/drivers/staging/r8188eu/core/rtw_cmd.c b/drivers/staging/r8188eu/core/rtw_cmd.c
index bdf0d0160070..3b07328704bb 100644
--- a/drivers/staging/r8188eu/core/rtw_cmd.c
+++ b/drivers/staging/r8188eu/core/rtw_cmd.c
@@ -21,7 +21,7 @@ static int _rtw_init_cmd_priv(struct cmd_priv *pcmdpriv)
 {
 	int res = _SUCCESS;
 
-	sema_init(&pcmdpriv->cmd_queue_sema, 0);
+	init_completion(&pcmdpriv->enqueue_cmd);
 	/* sema_init(&(pcmdpriv->cmd_done_sema), 0); */
 	init_completion(&pcmdpriv->start_cmd_thread);
 	init_completion(&pcmdpriv->stop_cmd_thread);
@@ -198,7 +198,7 @@ u32 rtw_enqueue_cmd(struct cmd_priv *pcmdpriv, struct cmd_obj *cmd_obj)
 	res = _rtw_enqueue_cmd(&pcmdpriv->cmd_queue, cmd_obj);
 
 	if (res == _SUCCESS)
-		up(&pcmdpriv->cmd_queue_sema);
+		complete(&pcmdpriv->enqueue_cmd);
 
 exit:
 
@@ -250,8 +250,7 @@ int rtw_cmd_thread(void *context)
 	complete(&pcmdpriv->start_cmd_thread);
 
 	while (1) {
-		if (_rtw_down_sema(&pcmdpriv->cmd_queue_sema) == _FAIL)
-			break;
+		wait_for_completion(&pcmdpriv->enqueue_cmd);
 
 		if (padapter->bDriverStopped ||
 		    padapter->bSurpriseRemoved) {
diff --git a/drivers/staging/r8188eu/include/rtw_cmd.h b/drivers/staging/r8188eu/include/rtw_cmd.h
index b6266e3e2c40..47c3c80cc24a 100644
--- a/drivers/staging/r8188eu/include/rtw_cmd.h
+++ b/drivers/staging/r8188eu/include/rtw_cmd.h
@@ -33,7 +33,7 @@ struct cmd_obj {
 };
 
 struct cmd_priv {
-	struct semaphore cmd_queue_sema;
+	struct completion enqueue_cmd;
 	struct completion start_cmd_thread;
 	struct completion stop_cmd_thread;
 	struct __queue cmd_queue;
diff --git a/drivers/staging/r8188eu/os_dep/os_intfs.c b/drivers/staging/r8188eu/os_dep/os_intfs.c
index 0bcea66f550b..96e9897085fe 100644
--- a/drivers/staging/r8188eu/os_dep/os_intfs.c
+++ b/drivers/staging/r8188eu/os_dep/os_intfs.c
@@ -394,7 +394,7 @@ u32 rtw_start_drv_threads(struct adapter *padapter)
 void rtw_stop_drv_threads(struct adapter *padapter)
 {
 	/* Below is to termindate rtw_cmd_thread & event_thread... */
-	up(&padapter->cmdpriv.cmd_queue_sema);
+	complete(&padapter->cmdpriv.enqueue_cmd);
 	if (padapter->cmdThread)
 		/* wait for rtw_cmd_thread() to stop running */
 		wait_for_completion(&padapter->cmdpriv.stop_cmd_thread);
-- 
2.33.0