linux-kernel - [PATCH][next] hwrng: exynos: check for -ve error return from readl_poll

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Message-Id: <20180112163048.26960-1-colin.king@canonical.com>
Date:   Fri, 12 Jan 2018 16:30:48 +0000
From:   Colin King <colin.king@...onical.com>
To:     Łukasz Stelmach <l.stelmach@...sung.com>,
        Matt Mackall <mpm@...enic.com>,
        Herbert Xu <herbert@...dor.apana.org.au>,
        Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Kukjin Kim <kgene@...nel.org>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        linux-samsung-soc@...r.kernel.org, linux-crypto@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org
Cc:     kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH][next] hwrng: exynos: check for -ve error return from readl_poll_timeout

From: Colin Ian King <colin.king@...onical.com>

Currently, the return from readl_poll_timeout is being assigned to
a u32 and this is being checked for a -ve return which is always
false since a u32 cannot be less than zero.  Fix this by changing
val to an int so that error returns can be correctly detected.

Detected by CoverityScan, CID#1463776 ("Logically dead code")

Fixes: 6cd225cc5d8a ("hwrng: exynos - add Samsung Exynos True RNG driver")
Signed-off-by: Colin Ian King <colin.king@...onical.com>
---
 drivers/char/hw_random/exynos-trng.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/char/hw_random/exynos-trng.c b/drivers/char/hw_random/exynos-trng.c
index 34d6f51ecbee..f4643e3ec346 100644
--- a/drivers/char/hw_random/exynos-trng.c
+++ b/drivers/char/hw_random/exynos-trng.c
@@ -55,7 +55,7 @@ static int exynos_trng_do_read(struct hwrng *rng, void *data, size_t max,
 			       bool wait)
 {
 	struct exynos_trng_dev *trng;
-	u32 val;
+	int val;
 
 	max = min_t(size_t, max, (EXYNOS_TRNG_FIFO_LEN * 4));
 
-- 
2.15.1