Re: [PATCH] pci: endpoint: Replace mdelay with usleep_range in pci_epf_test_write
From: Lorenzo Pieralisi
Date: Fri May 11 2018 - 10:18:48 EST
On Tue, Apr 10, 2018 at 09:04:06PM +0800, Jia-Ju Bai wrote:
> pci_epf_test_write() is never called in atomic context.
> The call chain ending up at pci_epf_test_write() is:
>  pci_epf_test_write() <- pci_epf_test_cmd_handler()
> pci_epf_test_cmd_handler() is set as a parameter of INIT_DELAYED_WORK()
> in pci_epf_test_probe().
> This function is not called in atomic context.
> Despite never getting called from atomic context, pci_epf_test_write()
> 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@xxxxxxxxx>
> drivers/pci/endpoint/functions/pci-epf-test.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
Applied to pci/endpoint for v4.18, thanks.
> diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
> index f9308c2..2f0642e 100644
> --- a/drivers/pci/endpoint/functions/pci-epf-test.c
> +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
> @@ -237,7 +237,7 @@ static int pci_epf_test_write(struct pci_epf_test *epf_test)
> * wait 1ms inorder for the write to complete. Without this delay L3
> * error in observed in the host system.
> - mdelay(1);
> + usleep_range(1000, 2000);