From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Subject: Re: [PATCH v2 1/3] mm: make dev_pagemap_mapping_shift() externally visible References: <20181109203921.178363-1-brho@google.com> <20181114215155.259978-1-brho@google.com> <20181114215155.259978-2-brho@google.com> From: Paolo Bonzini Message-ID: Date: Mon, 26 Nov 2018 17:50:22 +0100 MIME-Version: 1.0 In-Reply-To: <20181114215155.259978-2-brho@google.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Barret Rhoden , Dan Williams , Dave Jiang , Ross Zwisler , Vishal Verma , =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Naoya Horiguchi Cc: linux-nvdimm@lists.01.org, linux-kernel@vger.kernel.org, "H. Peter Anvin" , x86@kernel.org, kvm@vger.kernel.org, yu.c.zhang@intel.com, yi.z.zhang@intel.com, linux-mm@kvack.org, David Hildenbrand , Andrew Morton List-ID: On 14/11/18 22:51, Barret Rhoden wrote: > KVM has a use case for determining the size of a dax mapping. The KVM > code has easy access to the address and the mm; hence the change in > parameters. > > Signed-off-by: Barret Rhoden > Reviewed-by: David Hildenbrand > --- > include/linux/mm.h | 3 +++ > mm/memory-failure.c | 38 +++----------------------------------- > mm/util.c | 34 ++++++++++++++++++++++++++++++++++ > 3 files changed, 40 insertions(+), 35 deletions(-) > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index 5411de93a363..51215d695753 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -935,6 +935,9 @@ static inline bool is_pci_p2pdma_page(const struct page *page) > } > #endif /* CONFIG_DEV_PAGEMAP_OPS */ > > +unsigned long dev_pagemap_mapping_shift(unsigned long address, > + struct mm_struct *mm); > + > static inline void get_page(struct page *page) > { > page = compound_head(page); > diff --git a/mm/memory-failure.c b/mm/memory-failure.c > index 0cd3de3550f0..c3f2c6a8607e 100644 > --- a/mm/memory-failure.c > +++ b/mm/memory-failure.c > @@ -265,40 +265,6 @@ void shake_page(struct page *p, int access) > } > EXPORT_SYMBOL_GPL(shake_page); > > -static unsigned long dev_pagemap_mapping_shift(struct page *page, > - struct vm_area_struct *vma) > -{ > - unsigned long address = vma_address(page, vma); > - pgd_t *pgd; > - p4d_t *p4d; > - pud_t *pud; > - pmd_t *pmd; > - pte_t *pte; > - > - pgd = pgd_offset(vma->vm_mm, address); > - if (!pgd_present(*pgd)) > - return 0; > - p4d = p4d_offset(pgd, address); > - if (!p4d_present(*p4d)) > - return 0; > - pud = pud_offset(p4d, address); > - if (!pud_present(*pud)) > - return 0; > - if (pud_devmap(*pud)) > - return PUD_SHIFT; > - pmd = pmd_offset(pud, address); > - if (!pmd_present(*pmd)) > - return 0; > - if (pmd_devmap(*pmd)) > - return PMD_SHIFT; > - pte = pte_offset_map(pmd, address); > - if (!pte_present(*pte)) > - return 0; > - if (pte_devmap(*pte)) > - return PAGE_SHIFT; > - return 0; > -} > - > /* > * Failure handling: if we can't find or can't kill a process there's > * not much we can do. We just print a message and ignore otherwise. > @@ -329,7 +295,9 @@ static void add_to_kill(struct task_struct *tsk, struct page *p, > tk->addr = page_address_in_vma(p, vma); > tk->addr_valid = 1; > if (is_zone_device_page(p)) > - tk->size_shift = dev_pagemap_mapping_shift(p, vma); > + tk->size_shift = > + dev_pagemap_mapping_shift(vma_address(page, vma), > + vma->vm_mm); > else > tk->size_shift = compound_order(compound_head(p)) + PAGE_SHIFT; > > diff --git a/mm/util.c b/mm/util.c > index 8bf08b5b5760..61bc9bab931d 100644 > --- a/mm/util.c > +++ b/mm/util.c > @@ -780,3 +780,37 @@ int get_cmdline(struct task_struct *task, char *buffer, int buflen) > out: > return res; > } > + > +unsigned long dev_pagemap_mapping_shift(unsigned long address, > + struct mm_struct *mm) > +{ > + pgd_t *pgd; > + p4d_t *p4d; > + pud_t *pud; > + pmd_t *pmd; > + pte_t *pte; > + > + pgd = pgd_offset(mm, address); > + if (!pgd_present(*pgd)) > + return 0; > + p4d = p4d_offset(pgd, address); > + if (!p4d_present(*p4d)) > + return 0; > + pud = pud_offset(p4d, address); > + if (!pud_present(*pud)) > + return 0; > + if (pud_devmap(*pud)) > + return PUD_SHIFT; > + pmd = pmd_offset(pud, address); > + if (!pmd_present(*pmd)) > + return 0; > + if (pmd_devmap(*pmd)) > + return PMD_SHIFT; > + pte = pte_offset_map(pmd, address); > + if (!pte_present(*pte)) > + return 0; > + if (pte_devmap(*pte)) > + return PAGE_SHIFT; > + return 0; > +} > +EXPORT_SYMBOL_GPL(dev_pagemap_mapping_shift); > Andrew, can you ack this patch? Thanks, Paolo