[lkml]   [2018]   [Apr]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
Patch in this message
Subject[PATCH] pci: endpoint: Replace mdelay with usleep_range in pci_epf_test_write
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 <>
drivers/pci/endpoint/functions/pci-epf-test.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

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);


 \ /
  Last update: 2018-04-10 15:05    [W:0.098 / U:4.732 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site