LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Jia-Ju Bai <baijiaju1990@gmail.com>
To: kishon@ti.com, bhelgaas@google.com, nsekhar@ti.com,
	john@metanate.com, shawn.lin@rock-chips.com
Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
	Jia-Ju Bai <baijiaju1990@gmail.com>
Subject: [PATCH] pci: endpoint: Replace mdelay with usleep_range in pci_epf_test_write
Date: Tue, 10 Apr 2018 21:04:06 +0800	[thread overview]
Message-ID: <1523365446-31563-1-git-send-email-baijiaju1990@gmail.com> (raw)

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(-)

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

             reply	other threads:[~2018-04-10 13:04 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-10 13:04 Jia-Ju Bai [this message]
2018-05-04 16:29 ` Lorenzo Pieralisi
2018-05-05 10:03   ` Kishon Vijay Abraham I
2018-05-08 10:53 ` Lorenzo Pieralisi
2018-05-11 14:18 ` Lorenzo Pieralisi

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1523365446-31563-1-git-send-email-baijiaju1990@gmail.com \
    --to=baijiaju1990@gmail.com \
    --cc=bhelgaas@google.com \
    --cc=john@metanate.com \
    --cc=kishon@ti.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-pci@vger.kernel.org \
    --cc=nsekhar@ti.com \
    --cc=shawn.lin@rock-chips.com \
    --subject='Re: [PATCH] pci: endpoint: Replace mdelay with usleep_range in pci_epf_test_write' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).