linux-kernel - [PATCH V3] staging: fieldbus: anybus-s: consolidate wait_for_completion

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Message-Id: <1556517940-13725-2-git-send-email-hofrat@osadl.org>
Date:   Mon, 29 Apr 2019 08:05:40 +0200
From:   Nicholas Mc Guire <hofrat@...dl.org>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     Sven Van Asbroeck <thesven73@...il.com>,
        devel@...verdev.osuosl.org, linux-kernel@...r.kernel.org,
        Nicholas Mc Guire <hofrat@...dl.org>
Subject: [PATCH V3] staging: fieldbus: anybus-s: consolidate wait_for_completion_timeout return handling

wait_for_completion_timeout() returns unsigned long (0 on timeout or
remaining jiffies) not int - so this type error allows for a
theoretically int overflow - though not in this case where TIMEOUT is
only HZ*2). To fix this type inconsistency the completion is wrapped
into the if() rather than introducing an additional unsigned long
variable. 

Along with fixing this type inconsistency the fall-through if is
consolidated to a single if-block.

Signed-off-by: Nicholas Mc Guire <hofrat@...dl.org>
---

Problem located with experimental API conformance checking cocci script

V3: As requested by Sven Van Asbroeck <thesven73@...il.com> cleanup
    the commit message to make it more clear what the impact of the
    proposed change is....lets see if this is any better.

V2: The original patch's logic was wrong as it was skipping the 
    fall-through if so using the fix proposed by Sven Van Asbroeck 
    <thesven73@...il.com> - This solution also eliminates the need
    to introduce an additional variable - Thanks !

Patch was compile-tested with. x86_64_defconfig + OF=y, FIELDBUS_DEV=m,
HMS_ANYBUSS_BUS=m
(with an unrelated sparse warnings (cast to restricted __be16))

Patch is against 5.1-rc6 (localversion-next is next-20190426)

 drivers/staging/fieldbus/anybuss/host.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/staging/fieldbus/anybuss/host.c b/drivers/staging/fieldbus/anybuss/host.c
index e34d424..6227daf 100644
--- a/drivers/staging/fieldbus/anybuss/host.c
+++ b/drivers/staging/fieldbus/anybuss/host.c
@@ -1325,11 +1325,11 @@ anybuss_host_common_probe(struct device *dev,
 	 *   interrupt came in: ready to go !
 	 */
 	reset_deassert(cd);
-	ret = wait_for_completion_timeout(&cd->card_boot, TIMEOUT);
-	if (ret == 0)
+	if (!wait_for_completion_timeout(&cd->card_boot, TIMEOUT)) {
 		ret = -ETIMEDOUT;
-	if (ret < 0)
 		goto err_reset;
+	}
+
 	/*
 	 * according to the anybus docs, we're allowed to read these
 	 * without handshaking / reserving the area
-- 
2.1.4