2018-04-11 01:49:37

by Jia-Ju Bai

[permalink] [raw]
Subject: [PATCH 1/2] net: can: sja1000: Replace mdelay with usleep_range in peak_pci_probe

peak_pci_probe() is never called in atomic context.

peak_pci_probe() is set as ".probe" in struct pci_driver.

Despite never getting called from atomic context, peak_pci_probe()
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 <[email protected]>
---
drivers/net/can/sja1000/peak_pci.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/can/sja1000/peak_pci.c b/drivers/net/can/sja1000/peak_pci.c
index 131026f..48cf821 100644
--- a/drivers/net/can/sja1000/peak_pci.c
+++ b/drivers/net/can/sja1000/peak_pci.c
@@ -608,7 +608,7 @@ static int peak_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
writeb(0x00, cfg_base + PITA_GPIOICR);
/* Toggle reset */
writeb(0x05, cfg_base + PITA_MISC + 3);
- mdelay(5);
+ usleep_range(5000, 6000);
/* Leave parport mux mode */
writeb(0x04, cfg_base + PITA_MISC + 3);

--
1.9.1



2018-04-25 14:58:12

by Marc Kleine-Budde

[permalink] [raw]
Subject: Re: [PATCH 1/2] net: can: sja1000: Replace mdelay with usleep_range in peak_pci_probe

On 04/11/2018 03:42 AM, Jia-Ju Bai wrote:
> peak_pci_probe() is never called in atomic context.
>
> peak_pci_probe() is set as ".probe" in struct pci_driver.
>
> Despite never getting called from atomic context, peak_pci_probe()
> 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 <[email protected]>

Applied both to linux-can-next.

tnx,
Marc

--
Pengutronix e.K. | Marc Kleine-Budde |
Industrial Linux Solutions | Phone: +49-231-2826-924 |
Vertretung West/Dortmund | Fax: +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686 | http://www.pengutronix.de |


Attachments:
signature.asc (499.00 B)
OpenPGP digital signature