linux-kernel - [PATCH v2 1/2] mwifiex: initiate card-specific work atomically

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Date:   Mon,  1 May 2017 11:45:48 -0700
From:   Brian Norris <briannorris@...omium.org>
To:     Ganapathi Bhat <gbhat@...vell.com>,
        Nishant Sarmukadam <nishants@...vell.com>
Cc:     <linux-kernel@...r.kernel.org>,
        Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Kalle Valo <kvalo@...eaurora.org>,
        linux-wireless@...r.kernel.org,
        Brian Norris <briannorris@...omium.org>
Subject: [PATCH v2 1/2] mwifiex: initiate card-specific work atomically

The non-atomic test + set is a little awkward here, and it technically
means we might double-schedule work unnecessarily. AFAICT, this is not
really a problem, since the extra "work" will be a no-op (the flag(s)
will be cleared by then), but it's still an anti-pattern.

Rewrite this to use the atomic test_and_set_bit() helper instead.

Signed-off-by: Brian Norris <briannorris@...omium.org>
---
new in v2
---
 drivers/net/wireless/marvell/mwifiex/pcie.c | 13 +++++++++----
 drivers/net/wireless/marvell/mwifiex/sdio.c | 16 +++++-----------
 2 files changed, 14 insertions(+), 15 deletions(-)

diff --git a/drivers/net/wireless/marvell/mwifiex/pcie.c b/drivers/net/wireless/marvell/mwifiex/pcie.c
index ac62bce50e96..8e7d6f41a952 100644
--- a/drivers/net/wireless/marvell/mwifiex/pcie.c
+++ b/drivers/net/wireless/marvell/mwifiex/pcie.c
@@ -2837,12 +2837,17 @@ static void mwifiex_pcie_device_dump(struct mwifiex_adapter *adapter)
 {
 	struct pcie_service_card *card = adapter->card;
 
-	if (test_bit(MWIFIEX_IFACE_WORK_DEVICE_DUMP, &card->work_flags))
-		return;
+	if (!test_and_set_bit(MWIFIEX_IFACE_WORK_DEVICE_DUMP,
+			      &card->work_flags))
+		schedule_work(&card->work);
+}
 
-	set_bit(MWIFIEX_IFACE_WORK_DEVICE_DUMP, &card->work_flags);
+static void mwifiex_pcie_card_reset(struct mwifiex_adapter *adapter)
+{
+	struct pcie_service_card *card = adapter->card;
 
-	schedule_work(&card->work);
+	if (!test_and_set_bit(MWIFIEX_IFACE_WORK_CARD_RESET, &card->work_flags))
+		schedule_work(&card->work);
 }
 
 static void mwifiex_pcie_free_buffers(struct mwifiex_adapter *adapter)
diff --git a/drivers/net/wireless/marvell/mwifiex/sdio.c b/drivers/net/wireless/marvell/mwifiex/sdio.c
index 0af1c6733c92..d38d31bb9b79 100644
--- a/drivers/net/wireless/marvell/mwifiex/sdio.c
+++ b/drivers/net/wireless/marvell/mwifiex/sdio.c
@@ -2533,12 +2533,8 @@ static void mwifiex_sdio_card_reset(struct mwifiex_adapter *adapter)
 {
 	struct sdio_mmc_card *card = adapter->card;
 
-	if (test_bit(MWIFIEX_IFACE_WORK_CARD_RESET, &card->work_flags))
-		return;
-
-	set_bit(MWIFIEX_IFACE_WORK_CARD_RESET, &card->work_flags);
-
-	schedule_work(&card->work);
+	if (!test_and_set_bit(MWIFIEX_IFACE_WORK_CARD_RESET, &card->work_flags))
+		schedule_work(&card->work);
 }
 
 /* This function dumps FW information */
@@ -2546,11 +2542,9 @@ static void mwifiex_sdio_device_dump(struct mwifiex_adapter *adapter)
 {
 	struct sdio_mmc_card *card = adapter->card;
 
-	if (test_bit(MWIFIEX_IFACE_WORK_DEVICE_DUMP, &card->work_flags))
-		return;
-
-	set_bit(MWIFIEX_IFACE_WORK_DEVICE_DUMP, &card->work_flags);
-	schedule_work(&card->work);
+	if (!test_and_set_bit(MWIFIEX_IFACE_WORK_DEVICE_DUMP,
+			      &card->work_flags))
+		schedule_work(&card->work);
 }
 
 /* Function to dump SDIO function registers and SDIO scratch registers in case
-- 
2.13.0.rc0.306.g87b477812d-goog