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[85.228.174.190]) by smtp.gmail.com with ESMTPSA id f22sm7456128ljn.66.2020.06.29.06.06.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 29 Jun 2020 06:06:45 -0700 (PDT) Received: from johan by xi.terra with local (Exim 4.93.0.4) (envelope-from ) id 1jptUi-0007Vk-Lx; Mon, 29 Jun 2020 15:06:45 +0200 Date: Mon, 29 Jun 2020 15:06:44 +0200 From: Johan Hovold To: Lee Jones Subject: Re: [PATCH 4/5] mfd: sprd-sc27xx-spi: Fix divide by zero when allocating register offset/mask Message-ID: <20200629130644.GU3334@localhost> References: <20200629123215.1014747-1-lee.jones@linaro.org> <20200629123215.1014747-5-lee.jones@linaro.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200629123215.1014747-5-lee.jones@linaro.org> X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Baolin Wang , Orson Zhai , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Chunyan Zhang Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, Jun 29, 2020 at 01:32:14PM +0100, Lee Jones wrote: > Since ddata->irqs[] is already zeroed when allocated by devm_kcalloc() and > dividing 0 by anything is still 0, there is no need to re-assign > ddata->irqs[i].* values. Instead, it should be safe to begin at 1. > > This fixes the following W=1 warning: > > drivers/mfd/sprd-sc27xx-spi.c:255 sprd_pmic_probe() debug: sval_binop_unsigned: divide by zero > > Cc: Orson Zhai > Cc: Baolin Wang > Cc: Chunyan Zhang > Signed-off-by: Lee Jones > --- > drivers/mfd/sprd-sc27xx-spi.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/mfd/sprd-sc27xx-spi.c b/drivers/mfd/sprd-sc27xx-spi.c > index c305e941e435c..694a7d429ccff 100644 > --- a/drivers/mfd/sprd-sc27xx-spi.c > +++ b/drivers/mfd/sprd-sc27xx-spi.c > @@ -251,7 +251,7 @@ static int sprd_pmic_probe(struct spi_device *spi) > return -ENOMEM; > > ddata->irq_chip.irqs = ddata->irqs; > - for (i = 0; i < pdata->num_irqs; i++) { > + for (i = 1; i < pdata->num_irqs; i++) { > ddata->irqs[i].reg_offset = i / pdata->num_irqs; > ddata->irqs[i].mask = BIT(i % pdata->num_irqs); > } This doesn't look right either. First, the loop is never executed if num_irqs is zero. Second, the current code looks bogus too as reg_offset is always set to zero and mask to BIT(i)... Johan _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel