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From: Jia-Ju Bai <baijiaju1990@gmail.com>
To: tim@cyberelk.net
Cc: linux-kernel@vger.kernel.org, Jia-Ju Bai <baijiaju1990@gmail.com>
Subject: [PATCH] block: paride: on26: Replace mdelay with msleep in on26_test_port
Date: Fri, 26 Jan 2018 23:42:25 +0800	[thread overview]
Message-ID: <1516981345-8202-1-git-send-email-baijiaju1990@gmail.com> (raw)

After checking all possible call chains to on26_test_port() here,
my tool finds that this function is never called in atomic context,
namely never in an interrupt handler or holding a spinlock.
And on26_test_port() is only called by pi_probe_unit() that calls 
wait_event() through pi_claim(),
so it indicates that on26_test_port() can call functions that can sleep.
Thus mdelay can be replaced with msleep to avoid busy wait.

This is found by a static analysis tool named DCNS written by myself.

Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
---
 drivers/block/paride/on26.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/block/paride/on26.c b/drivers/block/paride/on26.c
index 95ba256..3240d6f 100644
--- a/drivers/block/paride/on26.c
+++ b/drivers/block/paride/on26.c
@@ -163,7 +163,7 @@ static int on26_test_port( PIA *pi)  /* hard reset */
                 on26_write_regr(pi,0,6,0xb0);
                 y = on26_read_regr(pi,0,7);
                 if (!((x&0x80)||(y&0x80))) break;
-                mdelay(100);
+                msleep(100);
             }
 
 	    if (i == RESET_WAIT) 
-- 
1.7.9.5

             reply	other threads:[~2018-01-26 15:37 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-26 15:42 Jia-Ju Bai [this message]
2018-01-26 17:31 ` Al Viro
2018-01-27  4:13   ` Jia-Ju Bai

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