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[216.228.121.64]) by mx.google.com with ESMTPS id s66si60386042pfs.120.2019.08.09.17.09.55 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 09 Aug 2019 17:09:56 -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=bpL5Ee4v; 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 hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqemgate15.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Fri, 09 Aug 2019 17:10:06 -0700 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Fri, 09 Aug 2019 17:09:55 -0700 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Fri, 09 Aug 2019 17:09:55 -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; Sat, 10 Aug 2019 00:09:55 +0000 Subject: Re: [RFC PATCH v2 15/19] mm/gup: Introduce vaddr_pin_pages() To: , Andrew Morton CC: Jason Gunthorpe , Dan Williams , Matthew Wilcox , Jan Kara , Theodore Ts'o , Michal Hocko , Dave Chinner , , , , , , , References: <20190809225833.6657-1-ira.weiny@intel.com> <20190809225833.6657-16-ira.weiny@intel.com> X-Nvconfidentiality: public From: John Hubbard Message-ID: <6ed26a08-4371-9dc1-09eb-7b8a4689d93b@nvidia.com> Date: Fri, 9 Aug 2019 17:09:54 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20190809225833.6657-16-ira.weiny@intel.com> X-Originating-IP: [172.20.13.39] X-ClientProxiedBy: HQMAIL107.nvidia.com (172.20.187.13) 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=1565395806; bh=6gNuzZAjPm1drI86ijnE4uQ1M9Dnne0kRHnh1Jmmh9I=; 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=bpL5Ee4vSwNJx48EaIgEa1vW54C9BYxOuHJZXR2g0DimV8Jbzh9FRHk15PHeXZMt7 3/XIvkM/NZxoMCLKXrSswHltiMKCAoppMwLtn2BNcmUd0Lw2sUJvyJyIaxd/yXSjd3 LaYgfDzJsY3KevnitA9y+5kH//XcswK9sOikrJXKW9xfdNJxmtenjCD/AWehvcHIik y5CZMfyYhk4QKlqgr+QjwyqQWwWhf7J8xk1xm0vY75awN4I9ewl+//BoHKekZfNLOK ZxUnp+fBKdqhMrKGLYc8mXDRC+MO6XRKOuvv/2u6Q8pmbWfnTuoDHXlQnv60eq+LZw O5Ypby3VqT9Wg== 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 8/9/19 3:58 PM, ira.weiny@intel.com wrote: > From: Ira Weiny > > The addition of FOLL_LONGTERM has taken on additional meaning for CMA > pages. > > In addition subsystems such as RDMA require new information to be passed > to the GUP interface to track file owning information. As such a simple > FOLL_LONGTERM flag is no longer sufficient for these users to pin pages. > > Introduce a new GUP like call which takes the newly introduced vaddr_pin > information. Failure to pass the vaddr_pin object back to a vaddr_put* > call will result in a failure if pins were created on files during the > pin operation. > > Signed-off-by: Ira Weiny > > --- > Changes from list: > Change to vaddr_put_pages_dirty_lock > Change to vaddr_unpin_pages_dirty_lock > > include/linux/mm.h | 5 ++++ > mm/gup.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 64 insertions(+) > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index 657c947bda49..90c5802866df 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -1603,6 +1603,11 @@ int account_locked_vm(struct mm_struct *mm, unsigned long pages, bool inc); > int __account_locked_vm(struct mm_struct *mm, unsigned long pages, bool inc, > struct task_struct *task, bool bypass_rlim); > > +long vaddr_pin_pages(unsigned long addr, unsigned long nr_pages, > + unsigned int gup_flags, struct page **pages, > + struct vaddr_pin *vaddr_pin); > +void vaddr_unpin_pages_dirty_lock(struct page **pages, unsigned long nr_pages, > + struct vaddr_pin *vaddr_pin, bool make_dirty); Hi Ira, OK, the API seems fine to me, anyway. :) A bit more below... > bool mapping_inode_has_layout(struct vaddr_pin *vaddr_pin, struct page *page); > > /* Container for pinned pfns / pages */ > diff --git a/mm/gup.c b/mm/gup.c > index eeaa0ddd08a6..6d23f70d7847 100644 > --- a/mm/gup.c > +++ b/mm/gup.c > @@ -2536,3 +2536,62 @@ int get_user_pages_fast(unsigned long start, int nr_pages, > return ret; > } > EXPORT_SYMBOL_GPL(get_user_pages_fast); > + > +/** > + * vaddr_pin_pages pin pages by virtual address and return the pages to the > + * user. > + * > + * @addr, start address What's with the commas? I thought kernel-doc wants colons, like this, right? @addr: start address > + * @nr_pages, number of pages to pin > + * @gup_flags, flags to use for the pin > + * @pages, array of pages returned > + * @vaddr_pin, initalized meta information this pin is to be associated > + * with. > + * > + * NOTE regarding vaddr_pin: > + * > + * Some callers can share pins via file descriptors to other processes. > + * Callers such as this should use the f_owner field of vaddr_pin to indicate > + * the file the fd points to. All other callers should use the mm this pin is > + * being made against. Usually "current->mm". > + * > + * Expects mmap_sem to be read locked. > + */ > +long vaddr_pin_pages(unsigned long addr, unsigned long nr_pages, > + unsigned int gup_flags, struct page **pages, > + struct vaddr_pin *vaddr_pin) > +{ > + long ret; > + > + gup_flags |= FOLL_LONGTERM; Is now the right time to introduce and use FOLL_PIN? If not, then I can always add it on top of this later, as part of gup-tracking patches. But you did point out that FOLL_LONGTERM is taking on additional meaning, and so maybe it's better to split that meaning up right from the start. > + > + if (!vaddr_pin || (!vaddr_pin->mm && !vaddr_pin->f_owner)) > + return -EINVAL; > + > + ret = __gup_longterm_locked(current, > + vaddr_pin->mm, > + addr, nr_pages, > + pages, NULL, gup_flags, > + vaddr_pin); > + return ret; > +} > +EXPORT_SYMBOL(vaddr_pin_pages); > + > +/** > + * vaddr_unpin_pages_dirty_lock - counterpart to vaddr_pin_pages > + * > + * @pages, array of pages returned > + * @nr_pages, number of pages in pages > + * @vaddr_pin, same information passed to vaddr_pin_pages > + * @make_dirty: whether to mark the pages dirty > + * > + * The semantics are similar to put_user_pages_dirty_lock but a vaddr_pin used > + * in vaddr_pin_pages should be passed back into this call for propper Typo: proper > + * tracking. > + */ > +void vaddr_unpin_pages_dirty_lock(struct page **pages, unsigned long nr_pages, > + struct vaddr_pin *vaddr_pin, bool make_dirty) > +{ > + __put_user_pages_dirty_lock(vaddr_pin, pages, nr_pages, make_dirty); > +} > +EXPORT_SYMBOL(vaddr_unpin_pages_dirty_lock); > OK, whew, I'm glad to see the updated _dirty_lock() API used here. :) thanks, -- John Hubbard NVIDIA