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[209.85.220.65]) by mx.google.com with SMTPS id b17sor77093328pjz.4.2019.07.30.08.40.09 for (Google Transport Security); Tue, 30 Jul 2019 08:40:09 -0700 (PDT) Received-SPF: pass (google.com: domain of linux.bhar@gmail.com designates 209.85.220.65 as permitted sender) client-ip=209.85.220.65; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=JnpuD7Lh; spf=pass (google.com: domain of linux.bhar@gmail.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=linux.bhar@gmail.com; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=VL69OhOnAwL0XYVUd4iryHVhyGAPtRV3TIOYsddsZuM=; b=JnpuD7Lhn/qE7XJv7n7efhB9Y1FFuZ2F4tOy7xPNk3kBOJquUa5ZdXVE2CaWJEsrVh yMfhPN5d3zlY7lks50LSVx43a9lRWN3fEw+2mRlkOtiPyWUiI+jM084e7+I7io06LwW4 kK68uPBHyuRVpRWRsz+aFk7D++UOdv1Lu2AkC6wYhYUrHLpHRAcI7yLQGzf4fxZ1UvEf MqI3XIEqPLJYE3iB6QcnVLgMG3zmHV68RS5MYxD0/c3AeU0Dct6278t6LVZ1T4B0j1Ew DlcnLz7xXh4kbs/9etasPC7viCglq3IR4SDSVF2nF9sw0Uiur+vimuBZvOX2mrvMzSNT 29Gw== X-Google-Smtp-Source: APXvYqxzMdxms+bc78CL5gsMck7qwh7ISTe+alN65NyxUVXjwyMgBoEubKQB6gleAbfiP0OgFFPVqg== X-Received: by 2002:a17:90a:8a0b:: with SMTP id w11mr116924577pjn.125.1564501209516; Tue, 30 Jul 2019 08:40:09 -0700 (PDT) Received: from bharath12345-Inspiron-5559 ([103.110.42.33]) by smtp.gmail.com with ESMTPSA id 67sm36860864pfd.177.2019.07.30.08.40.08 (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 30 Jul 2019 08:40:09 -0700 (PDT) From: Bharath Vedartham To: sivanich@sgi.com, arnd@arndb.de Cc: ira.weiny@intel.com, jhubbard@nvidia.com, jglisse@redhat.com, gregkh@linuxfoundation.org, william.kucharski@oracle.com, hch@lst.de, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-kernel-mentees@lists.linuxfoundation.org, Bharath Vedartham Subject: [Linux-kernel-mentees][PATCH v4 1/1] sgi-gru: Remove *pte_lookup functions Date: Tue, 30 Jul 2019 21:09:30 +0530 Message-Id: <1564501170-6830-2-git-send-email-linux.bhar@gmail.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1564501170-6830-1-git-send-email-linux.bhar@gmail.com> References: <1564501170-6830-1-git-send-email-linux.bhar@gmail.com> MIME-Version: 1.0 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: X-Virus-Scanned: ClamAV using ClamSMTP The *pte_lookup functions can be removed and be easily replaced with get_user_pages_fast functions. In the case of atomic lookup, __get_user_pages_fast is used which does not fall back to slow get_user_pages. get_user_pages_fast on the other hand tries to use __get_user_pages_fast but fallbacks to slow get_user_pages if __get_user_pages_fast fails. Also unnecessary ifdefs to check for CONFIG_HUGETLB is removed as the check is redundant. Cc: Ira Weiny Cc: John Hubbard Cc: Jérôme Glisse Cc: Greg Kroah-Hartman Cc: Dimitri Sivanich Cc: Arnd Bergmann Cc: William Kucharski Cc: Christoph Hellwig Cc: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org Cc: linux-kernel-mentees@lists.linuxfoundation.org Reviewed-by: Ira Weiny Reviewed-by: John Hubbard Reviewed-by: William Kucharski Signed-off-by: Bharath Vedartham --- This is a fold of the 3 patches in the v2 patch series. The review tags were given to the individual patches. Changes since v3 - Used gup flags in get_user_pages_fast rather than boolean flags. --- drivers/misc/sgi-gru/grufault.c | 112 +++++++++------------------------------- 1 file changed, 24 insertions(+), 88 deletions(-) diff --git a/drivers/misc/sgi-gru/grufault.c b/drivers/misc/sgi-gru/grufault.c index 4b713a8..304e9c5 100644 --- a/drivers/misc/sgi-gru/grufault.c +++ b/drivers/misc/sgi-gru/grufault.c @@ -166,96 +166,20 @@ static void get_clear_fault_map(struct gru_state *gru, } /* - * Atomic (interrupt context) & non-atomic (user context) functions to - * convert a vaddr into a physical address. The size of the page - * is returned in pageshift. - * returns: - * 0 - successful - * < 0 - error code - * 1 - (atomic only) try again in non-atomic context - */ -static int non_atomic_pte_lookup(struct vm_area_struct *vma, - unsigned long vaddr, int write, - unsigned long *paddr, int *pageshift) -{ - struct page *page; - -#ifdef CONFIG_HUGETLB_PAGE - *pageshift = is_vm_hugetlb_page(vma) ? HPAGE_SHIFT : PAGE_SHIFT; -#else - *pageshift = PAGE_SHIFT; -#endif - if (get_user_pages(vaddr, 1, write ? FOLL_WRITE : 0, &page, NULL) <= 0) - return -EFAULT; - *paddr = page_to_phys(page); - put_page(page); - return 0; -} - -/* - * atomic_pte_lookup + * mmap_sem is already helod on entry to this function. This guarantees + * existence of the page tables. * - * Convert a user virtual address to a physical address * Only supports Intel large pages (2MB only) on x86_64. - * ZZZ - hugepage support is incomplete - * - * NOTE: mmap_sem is already held on entry to this function. This - * guarantees existence of the page tables. + * ZZZ - hugepage support is incomplete. */ -static int atomic_pte_lookup(struct vm_area_struct *vma, unsigned long vaddr, - int write, unsigned long *paddr, int *pageshift) -{ - pgd_t *pgdp; - p4d_t *p4dp; - pud_t *pudp; - pmd_t *pmdp; - pte_t pte; - - pgdp = pgd_offset(vma->vm_mm, vaddr); - if (unlikely(pgd_none(*pgdp))) - goto err; - - p4dp = p4d_offset(pgdp, vaddr); - if (unlikely(p4d_none(*p4dp))) - goto err; - - pudp = pud_offset(p4dp, vaddr); - if (unlikely(pud_none(*pudp))) - goto err; - - pmdp = pmd_offset(pudp, vaddr); - if (unlikely(pmd_none(*pmdp))) - goto err; -#ifdef CONFIG_X86_64 - if (unlikely(pmd_large(*pmdp))) - pte = *(pte_t *) pmdp; - else -#endif - pte = *pte_offset_kernel(pmdp, vaddr); - - if (unlikely(!pte_present(pte) || - (write && (!pte_write(pte) || !pte_dirty(pte))))) - return 1; - - *paddr = pte_pfn(pte) << PAGE_SHIFT; -#ifdef CONFIG_HUGETLB_PAGE - *pageshift = is_vm_hugetlb_page(vma) ? HPAGE_SHIFT : PAGE_SHIFT; -#else - *pageshift = PAGE_SHIFT; -#endif - return 0; - -err: - return 1; -} - static int gru_vtop(struct gru_thread_state *gts, unsigned long vaddr, int write, int atomic, unsigned long *gpa, int *pageshift) { struct mm_struct *mm = gts->ts_mm; struct vm_area_struct *vma; unsigned long paddr; - int ret, ps; + int ret; + struct page *page; vma = find_vma(mm, vaddr); if (!vma) @@ -263,21 +187,33 @@ static int gru_vtop(struct gru_thread_state *gts, unsigned long vaddr, /* * Atomic lookup is faster & usually works even if called in non-atomic - * context. + * context. get_user_pages_fast does atomic lookup before falling back to + * slow gup. */ rmb(); /* Must/check ms_range_active before loading PTEs */ - ret = atomic_pte_lookup(vma, vaddr, write, &paddr, &ps); - if (ret) { - if (atomic) + if (atomic) { + ret = __get_user_pages_fast(vaddr, 1, write, &page); + if (!ret) goto upm; - if (non_atomic_pte_lookup(vma, vaddr, write, &paddr, &ps)) + } else { + ret = get_user_pages_fast(vaddr, 1, write ? FOLL_WRITE : 0, &page); + if (!ret) goto inval; } + + paddr = page_to_phys(page); + put_user_page(page); + + if (unlikely(is_vm_hugetlb_page(vma))) + *pageshift = HPAGE_SHIFT; + else + *pageshift = PAGE_SHIFT; + if (is_gru_paddr(paddr)) goto inval; - paddr = paddr & ~((1UL << ps) - 1); + paddr = paddr & ~((1UL << *pageshift) - 1); *gpa = uv_soc_phys_ram_to_gpa(paddr); - *pageshift = ps; + return VTOP_SUCCESS; inval: