Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752516AbbKIB6L (ORCPT ); Sun, 8 Nov 2015 20:58:11 -0500 Received: from smtp.codeaurora.org ([198.145.29.96]:34476 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752369AbbKIB6G (ORCPT ); Sun, 8 Nov 2015 20:58:06 -0500 From: Sinan Kaya To: linux-scsi@vger.kernel.org, timur@codeaurora.org, cov@codeaurora.org, jcm@redhat.com Cc: agross@codeaurora.org, linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Sinan Kaya , Doug Gilbert , "James E.J. Bottomley" , linux-kernel@vger.kernel.org Subject: [PATCH V2 2/3] scsi: fix compiler warning for sg Date: Sun, 8 Nov 2015 20:57:45 -0500 Message-Id: <1447034266-28003-3-git-send-email-okaya@codeaurora.org> X-Mailer: git-send-email 1.8.2.1 In-Reply-To: <1447034266-28003-1-git-send-email-okaya@codeaurora.org> References: <1447034266-28003-1-git-send-email-okaya@codeaurora.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2489 Lines: 67 The MULDIV macro has been designed for small numbers. Compiler emits an overflow warning on 64 bit systems. This patch uses 64 bit numbers in order to suppress warning. Signed-off-by: Sinan Kaya --- drivers/scsi/sg.c | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-) diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c index 9d7b7db..112d8974 100644 --- a/drivers/scsi/sg.c +++ b/drivers/scsi/sg.c @@ -51,6 +51,7 @@ static int sg_version_num = 30536; /* 2 digits for each component */ #include #include #include +#include #include "scsi.h" #include @@ -85,12 +86,17 @@ static void sg_proc_cleanup(void); * Replacing muldiv(x) by muldiv(x)=((x % d) * m) / d + int(x / d) * m * calculates the same, but prevents the overflow when both m and d * are "small" numbers (like HZ and USER_HZ). - * Of course an overflow is inavoidable if the result of muldiv doesn't fit - * in 32 bits. */ -#define MULDIV(X,MUL,DIV) ((((X % DIV) * MUL) / DIV) + ((X / DIV) * MUL)) +static inline u64 mult_frac64(u64 x, u32 numer, u32 denom) +{ + u64 r1 = do_div(x, denom); + u64 r2 = r1 * numer; + + do_div(r2, denom); + return (x * numer) + r2; +} -#define SG_DEFAULT_TIMEOUT MULDIV(SG_DEFAULT_TIMEOUT_USER, HZ, USER_HZ) +#define SG_DEFAULT_TIMEOUT mult_frac64(SG_DEFAULT_TIMEOUT_USER, HZ, USER_HZ) int sg_big_buff = SG_DEF_RESERVED_SIZE; /* N.B. This variable is readable and writeable via @@ -877,10 +883,10 @@ sg_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg) return result; if (val < 0) return -EIO; - if (val >= MULDIV (INT_MAX, USER_HZ, HZ)) - val = MULDIV (INT_MAX, USER_HZ, HZ); + if (val >= mult_frac64(INT_MAX, USER_HZ, HZ)) + val = mult_frac64(INT_MAX, USER_HZ, HZ); sfp->timeout_user = val; - sfp->timeout = MULDIV (val, HZ, USER_HZ); + sfp->timeout = mult_frac64(val, HZ, USER_HZ); return 0; case SG_GET_TIMEOUT: /* N.B. User receives timeout as return value */ -- Qualcomm Technologies, Inc. on behalf of Qualcomm Innovation Center, Inc. Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/