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From:   Jia-Ju Bai <baijiaju1990@gmail.com>
To:     isdn@linux-pingi.de, davem@davemloft.net, johannes.berg@intel.com,
        arvind.yadav.cs@gmail.com, stephen@networkplumber.org
Cc:     netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        Jia-Ju Bai <baijiaju1990@gmail.com>
Subject: [PATCH 1/2] isdn: hisax_fcpcipnp: Replace mdelay with usleep_range in fcpci_init
Date:   Wed, 11 Apr 2018 11:33:37 +0800
Message-Id: <1523417617-3249-1-git-send-email-baijiaju1990@gmail.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

fcpci_init() is never called in atomic context.

The call chain ending up at fcpci_init() is:
[1] fcpci_init() <- fcpcipnp_setup() <- fcpnp_probe()

fcpnp_probe() is set as ".probe" in struct pnp_driver.
This function is not called in atomic context.

Despite never getting called from atomic context, fcpci_init()
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/isdn/hisax/hisax_fcpcipnp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/isdn/hisax/hisax_fcpcipnp.c b/drivers/isdn/hisax/hisax_fcpcipnp.c
index e4f7573..4789c9d 100644
--- a/drivers/isdn/hisax/hisax_fcpcipnp.c
+++ b/drivers/isdn/hisax/hisax_fcpcipnp.c
@@ -706,7 +706,7 @@ static inline void fcpci_init(struct fritz_adapter *adapter)
 
 	outb(AVM_STATUS1_ENA_IOM | adapter->irq,
 	     adapter->io + AVM_STATUS1);
-	mdelay(10);
+	usleep_range(10000, 11000);
 }
 
 // ----------------------------------------------------------------------
-- 
1.9.1