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a="181522498" X-IronPort-AV: E=Sophos;i="5.82,319,1613462400"; d="scan'208";a="181522498" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 May 2021 01:32:49 -0700 IronPort-SDR: xKvBDVuvApWl8/zkNcSAeRGqfD+yyfzCpxzXwHSUPLa1jR8N7Z1KdvAgT1AtPxjtD8Fn4sht7p EBdWR4VfH2Ew== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.82,319,1613462400"; d="scan'208";a="442721576" Received: from shbuild999.sh.intel.com (HELO localhost) ([10.239.147.94]) by fmsmga008.fm.intel.com with ESMTP; 24 May 2021 01:32:44 -0700 Date: Mon, 24 May 2021 16:32:43 +0800 From: Feng Tang To: David Rientjes Cc: "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , Andrew Morton , Michal Hocko , Andrea Arcangeli , Mel Gorman , Mike Kravetz , Randy Dunlap , Vlastimil Babka , "Hansen, Dave" , "Widawsky, Ben" , Andi Kleen , "Williams, Dan J" , "Huang, Ying" Subject: Re: [RFC Patch v2 2/4] mm/mempolicy: unify the preprocessing for mbind and set_mempolicy Message-ID: <20210524083243.GA11142@shbuild999.sh.intel.com> References: <1621499404-67756-1-git-send-email-feng.tang@intel.com> <1621499404-67756-3-git-send-email-feng.tang@intel.com> <7a58082-eb68-744c-93b7-1a688b3b27a@google.com> <20210524055939.GB48704@shbuild999.sh.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210524055939.GB48704@shbuild999.sh.intel.com> User-Agent: Mutt/1.5.24 (2015-08-30) Authentication-Results: imf15.hostedemail.com; dkim=none; dmarc=fail reason="No valid SPF, No valid DKIM" header.from=intel.com (policy=none); spf=none (imf15.hostedemail.com: domain of feng.tang@intel.com has no SPF policy when checking 192.55.52.136) smtp.mailfrom=feng.tang@intel.com X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 1F5A0A0001C0 X-Stat-Signature: 7e7wu5tpg83fwq4apqkrdjona5uo1w8m X-HE-Tag: 1621845170-780512 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, May 24, 2021 at 01:59:39PM +0800, Tang, Feng wrote: > On Sun, May 23, 2021 at 10:16:11PM -0700, David Rientjes wrote: > > On Thu, 20 May 2021, Feng Tang wrote: > > > > > Currently the kernel_mbind() and kernel_set_mempolicy() do almost > > > the same operation for parameter sanity check and preprocessing. > > > > > > Add a macro to unify the code to reduce the redundancy, and make > > > it easier for changing the pre-processing code in future. > > > > > > Signed-off-by: Feng Tang > > > --- > > > mm/mempolicy.c | 46 +++++++++++++++++++--------------------------- > > > 1 file changed, 19 insertions(+), 27 deletions(-) > > > > > > diff --git a/mm/mempolicy.c b/mm/mempolicy.c > > > index 1964cca..0f5bf60 100644 > > > --- a/mm/mempolicy.c > > > +++ b/mm/mempolicy.c > > > @@ -1460,25 +1460,29 @@ static int copy_nodes_to_user(unsigned long __user *mask, unsigned long maxnode, > > > return copy_to_user(mask, nodes_addr(*nodes), copy) ? -EFAULT : 0; > > > } > > > > > > +#define MPOL_PRE_PROCESS() \ > > > > This should be extracted to helper function returning bool, not a macro. > > Yes, initially I did try it with an inline function, but as a function > it has quite several input parameters and several output parameters, > which made the code still big and ugly. > > But if community think it's the right direction to go, I can change it. Following is a patch to unify the preprocssing by using a helper function, please review, thanks - Feng --- diff --git a/mm/mempolicy.c b/mm/mempolicy.c index d79fa299b70c..8e4f47f925b6 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -1460,6 +1460,20 @@ static int copy_nodes_to_user(unsigned long __user *mask, unsigned long maxnode, return copy_to_user(mask, nodes_addr(*nodes), copy) ? -EFAULT : 0; } +static inline int mpol_pre_process(int *mode, const unsigned long __user *nmask, unsigned long maxnode, nodemask_t *nodes, unsigned short *flags) +{ + int ret; + + *flags = *mode & MPOL_MODE_FLAGS; + *mode &= ~MPOL_MODE_FLAGS; + if ((unsigned int)(*mode) >= MPOL_MAX) + return -EINVAL; + if ((*flags & MPOL_F_STATIC_NODES) && (*flags & MPOL_F_RELATIVE_NODES)) + return -EINVAL; + ret = get_nodes(nodes, nmask, maxnode); + return ret; +} + static long kernel_mbind(unsigned long start, unsigned long len, unsigned long mode, const unsigned long __user *nmask, unsigned long maxnode, unsigned int flags) @@ -1467,19 +1481,14 @@ static long kernel_mbind(unsigned long start, unsigned long len, nodemask_t nodes; int err; unsigned short mode_flags; + int lmode = mode; - start = untagged_addr(start); - mode_flags = mode & MPOL_MODE_FLAGS; - mode &= ~MPOL_MODE_FLAGS; - if (mode >= MPOL_MAX) - return -EINVAL; - if ((mode_flags & MPOL_F_STATIC_NODES) && - (mode_flags & MPOL_F_RELATIVE_NODES)) - return -EINVAL; - err = get_nodes(&nodes, nmask, maxnode); + err = mpol_pre_process(&lmode, nmask, maxnode, &nodes, &mode_flags); if (err) return err; - return do_mbind(start, len, mode, mode_flags, &nodes, flags); + + start = untagged_addr(start); + return do_mbind(start, len, lmode, mode_flags, &nodes, flags); } SYSCALL_DEFINE6(mbind, unsigned long, start, unsigned long, len, @@ -1495,18 +1504,14 @@ static long kernel_set_mempolicy(int mode, const unsigned long __user *nmask, { int err; nodemask_t nodes; - unsigned short flags; + unsigned short mode_flags; + int lmode = mode; - flags = mode & MPOL_MODE_FLAGS; - mode &= ~MPOL_MODE_FLAGS; - if ((unsigned int)mode >= MPOL_MAX) - return -EINVAL; - if ((flags & MPOL_F_STATIC_NODES) && (flags & MPOL_F_RELATIVE_NODES)) - return -EINVAL; - err = get_nodes(&nodes, nmask, maxnode); + err = mpol_pre_process(&lmode, nmask, maxnode, &nodes, &mode_flags); if (err) return err; - return do_set_mempolicy(mode, flags, &nodes); + + return do_set_mempolicy(lmode, mode_flags, &nodes); } SYSCALL_DEFINE3(set_mempolicy, int, mode, const unsigned long __user *, nmask,