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[216.228.121.64]) by mx.google.com with ESMTPS id 14si5486349ybf.402.2019.06.04.12.38.03 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 04 Jun 2019 12:38:03 -0700 (PDT) Received-SPF: pass (google.com: domain of jhubbard@nvidia.com designates 216.228.121.64 as permitted sender) client-ip=216.228.121.64; Authentication-Results: mx.google.com; dkim=pass header.i=@nvidia.com header.s=n1 header.b=FXoMc9du; spf=pass (google.com: domain of jhubbard@nvidia.com designates 216.228.121.64 as permitted sender) smtp.mailfrom=jhubbard@nvidia.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=nvidia.com Received: from hqpgpgate102.nvidia.com (Not Verified[216.228.121.13]) by hqemgate15.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Tue, 04 Jun 2019 12:37:49 -0700 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate102.nvidia.com (PGP Universal service); Tue, 04 Jun 2019 12:38:02 -0700 X-PGP-Universal: processed; by hqpgpgate102.nvidia.com on Tue, 04 Jun 2019 12:38:02 -0700 Received: from [10.110.48.28] (172.20.13.39) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Tue, 4 Jun 2019 19:38:02 +0000 Subject: Re: [PATCHv2 1/2] mm/gup: fix omission of check on FOLL_LONGTERM in get_user_pages_fast() To: Ira Weiny , Christoph Hellwig CC: Pingfan Liu , , Andrew Morton , Mike Rapoport , Dan Williams , Matthew Wilcox , Aneesh Kumar K.V , Keith Busch , References: <1559543653-13185-1-git-send-email-kernelfans@gmail.com> <20190603164206.GB29719@infradead.org> <20190603235610.GB29018@iweiny-DESK2.sc.intel.com> <20190604070808.GA28858@infradead.org> <20190604165533.GA3980@iweiny-DESK2.sc.intel.com> X-Nvconfidentiality: public From: John Hubbard Message-ID: Date: Tue, 4 Jun 2019 12:38:01 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: <20190604165533.GA3980@iweiny-DESK2.sc.intel.com> X-Originating-IP: [172.20.13.39] X-ClientProxiedBy: HQMAIL106.nvidia.com (172.18.146.12) To HQMAIL107.nvidia.com (172.20.187.13) Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1559677069; bh=lIhxOsA9OCHLVcsFXFBTh63vXKqw/oUiHBUnBqTQTXA=; h=X-PGP-Universal:Subject:To:CC:References:X-Nvconfidentiality:From: Message-ID:Date:User-Agent:MIME-Version:In-Reply-To: X-Originating-IP:X-ClientProxiedBy:Content-Type:Content-Language: Content-Transfer-Encoding; b=FXoMc9dukyinG2w2j6LgNDON/dcWawP8WF6kN06Mt/GMuCzrpvC2YJ0uCN1OCeE5L QIch35Q5uHWL1NgN9iPZBZMdTyGNGebrWNWopsgBCaDHPfIkHlqULpi0kq/RearpDB b5Q1G/d4cTMi+a5wDrVzpaAWLH08HMk1+r5fMQajaKPJOIS28paAvNuUQc/MQprc0i TukcfTSZTltBtJxuXPG1lbt1VunG2qk4hyAnOZOB26xC6dZzuEc0VqBTgSF8A5CX10 77sY1bwc2HndVFLJkqNFl3PkJejPUNLMcFzjyyjvibqXB6ivb8mLJ3ju5ZULYqj+sN mWoPuSX3a2I3Q== 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 6/4/19 9:55 AM, Ira Weiny wrote: > On Tue, Jun 04, 2019 at 12:08:08AM -0700, Christoph Hellwig wrote: >> On Mon, Jun 03, 2019 at 04:56:10PM -0700, Ira Weiny wrote: >>> On Mon, Jun 03, 2019 at 09:42:06AM -0700, Christoph Hellwig wrote: >>>>> +#if defined(CONFIG_CMA) >>>> >>>> You can just use #ifdef here. >>>> >>>>> +static inline int reject_cma_pages(int nr_pinned, unsigned int gup_flags, >>>>> + struct page **pages) >>>> >>>> Please use two instead of one tab to indent the continuing line of >>>> a function declaration. >>>> >>>>> +{ >>>>> + if (unlikely(gup_flags & FOLL_LONGTERM)) { >>>> >>>> IMHO it would be a little nicer if we could move this into the caller. >>> >>> FWIW we already had this discussion and thought it better to put this here. >>> >>> https://lkml.org/lkml/2019/5/30/1565 >> >> I don't see any discussion like this. FYI, this is what I mean, >> code might be easier than words: > > Indeed that is more clear. My apologies. > > Ira > >> >> >> diff --git a/mm/gup.c b/mm/gup.c >> index ddde097cf9e4..62d770b18e2c 100644 >> --- a/mm/gup.c >> +++ b/mm/gup.c >> @@ -2197,6 +2197,27 @@ static int __gup_longterm_unlocked(unsigned long start, int nr_pages, >> return ret; >> } >> >> +#ifdef CONFIG_CMA >> +static int reject_cma_pages(struct page **pages, int nr_pinned) >> +{ >> + int i = 0; >> + >> + for (i = 0; i < nr_pinned; i++) >> + if (is_migrate_cma_page(pages[i])) { >> + put_user_pages(pages + i, nr_pinned - i); >> + return i; >> + } >> + } >> + >> + return nr_pinned; >> +} >> +#else >> +static inline int reject_cma_pages(struct page **pages, int nr_pinned) >> +{ >> + return nr_pinned; >> +} >> +#endif /* CONFIG_CMA */ >> + >> /** >> * get_user_pages_fast() - pin user pages in memory >> * @start: starting user address >> @@ -2237,6 +2258,9 @@ int get_user_pages_fast(unsigned long start, int nr_pages, >> ret = nr; >> } >> >> + if (nr && unlikely(gup_flags & FOLL_LONGTERM)) >> + nr = reject_cma_pages(pages, nr); >> + Yes, now I see what you meant, and agree that that is cleaner. thanks, -- John Hubbard NVIDIA >> if (nr < nr_pages) { >> /* Try to get the remaining pages with get_user_pages */ >> start += nr << PAGE_SHIFT; >>