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SubjectRe: [PATCH] pci: endpoint: Replace mdelay with usleep_range in pci_epf_test_write
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:
> [1] 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@gmail.com>
> ---
> drivers/pci/endpoint/functions/pci-epf-test.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)

Applied to pci/endpoint for v4.18, thanks.

Lorenzo

> 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);
>
> kfree(buf);
>
> --
> 1.9.1
>

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