From: Jia-Ju Bai <baijiaju1990@gmail.com>
To: wg@grandegger.com, mkl@pengutronix.de
Cc: linux-can@vger.kernel.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org, Jia-Ju Bai <baijiaju1990@gmail.com>
Subject: [PATCH 2/2] net: can: sja1000: Replace mdelay with usleep_range in pcan_add_channels
Date: Wed, 11 Apr 2018 09:43:26 +0800 [thread overview]
Message-ID: <1523411006-1905-1-git-send-email-baijiaju1990@gmail.com> (raw)
pcan_add_channels() is never called in atomic context.
pcan_add_channels() is only called by pcan_probe(), which is only set as
".probe" in struct pcmcia_driver.
Despite never getting called from atomic context, pcan_add_channels()
calls mdelay() to busily wait.
This is not necessary and can be replaced with usleep_range() to
avoid busy waiting.
This is found by a static analysis tool named DCNS written by myself.
And I also manually check it.
Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
---
drivers/net/can/sja1000/peak_pcmcia.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/can/sja1000/peak_pcmcia.c b/drivers/net/can/sja1000/peak_pcmcia.c
index dd56133..1a1fbf3 100644
--- a/drivers/net/can/sja1000/peak_pcmcia.c
+++ b/drivers/net/can/sja1000/peak_pcmcia.c
@@ -530,7 +530,7 @@ static int pcan_add_channels(struct pcan_pccard *card)
pcan_write_reg(card, PCC_CCR, ccr);
/* wait 2ms before unresetting channels */
- mdelay(2);
+ usleep_range(2000, 3000);
ccr &= ~PCC_CCR_RST_ALL;
pcan_write_reg(card, PCC_CCR, ccr);
--
1.9.1
reply other threads:[~2018-04-11 1:43 UTC|newest]
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