From: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com> To: Michael Holzheu <holzheu@linux.vnet.ibm.com> Cc: HATAYAMA Daisuke <d.hatayama@gmail.com>, Heiko Carstens <heiko.carstens@de.ibm.com>, kexec@lists.infradead.org, Jan Willeke <willeke@de.ibm.com>, linux-kernel@vger.kernel.org, Martin Schwidefsky <schwidefsky@de.ibm.com>, Vivek Goyal <vgoyal@redhat.com> Subject: Re: [PATCH v5 3/5] vmcore: Introduce remap_oldmem_pfn_range() Date: Thu, 13 Jun 2013 10:32:48 +0900 [thread overview] Message-ID: <51B92140.9050407@jp.fujitsu.com> (raw) In-Reply-To: <20130612111303.3323f24f@holzheu> (2013/06/12 18:13), Michael Holzheu wrote: > On Tue, 11 Jun 2013 21:42:15 +0900 > HATAYAMA Daisuke <d.hatayama@gmail.com> wrote: > >> 2013/6/11 Michael Holzheu <holzheu@linux.vnet.ibm.com>: >>> On Mon, 10 Jun 2013 22:40:24 +0900 >>> HATAYAMA Daisuke <d.hatayama@gmail.com> wrote: >>> >>>> 2013/6/8 Michael Holzheu <holzheu@linux.vnet.ibm.com>: <cut> > static int mmap_vmcore_fault(struct vm_area_struct *vma, struct'vm_fault *vmf) > { > struct address_space *mapping = vma->vm_private_data; > pgoff_t index = vmf->pgoff; > struct page *page; > loff_t src; > char *buf; > > page = find_or_create_page(mapping, index, GFP_KERNEL); > if (!page) > return VM_FAULT_OOM; > if (!PageUptodate(page)) { > src = index << PAGE_CACHE_SHIFT; > buf = (void *) (page_to_pfn(page) << PAGE_SHIFT); > if (__read_vmcore(buf, PAGE_SIZE, &src, 0) < 0) { > unlock_page(page); > return VM_FAULT_SIGBUS; > } > SetPageUptodate(page); > } > unlock_page(page); > vmf->page = page; > return 0; > } > > Perhaps one open issue remains: > > Can we remove the page from the page cache if __read_vmcore() fails? > Yes, use page_cache_release() after unlocking the page like: if (__read_vmcore(buf, PAGE_SIZE, &src, 0) < 0) { unlock_page(page); + page_cache_release(page); return VM_FAULT_SIGBUS; } BTW, you now keep file->f_mapping in vma->vm_private_data, but the vma already has the file object in its vma->vm_file member. You can get the mapping by vma->vm_file->f_mapping without necessity of vma->vm_private_data. -- Thanks. HATAYAMA, Daisuke
WARNING: multiple messages have this Message-ID (diff)
From: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com> To: Michael Holzheu <holzheu@linux.vnet.ibm.com> Cc: kexec@lists.infradead.org, Heiko Carstens <heiko.carstens@de.ibm.com>, linux-kernel@vger.kernel.org, Jan Willeke <willeke@de.ibm.com>, HATAYAMA Daisuke <d.hatayama@gmail.com>, Martin Schwidefsky <schwidefsky@de.ibm.com>, Vivek Goyal <vgoyal@redhat.com> Subject: Re: [PATCH v5 3/5] vmcore: Introduce remap_oldmem_pfn_range() Date: Thu, 13 Jun 2013 10:32:48 +0900 [thread overview] Message-ID: <51B92140.9050407@jp.fujitsu.com> (raw) In-Reply-To: <20130612111303.3323f24f@holzheu> (2013/06/12 18:13), Michael Holzheu wrote: > On Tue, 11 Jun 2013 21:42:15 +0900 > HATAYAMA Daisuke <d.hatayama@gmail.com> wrote: > >> 2013/6/11 Michael Holzheu <holzheu@linux.vnet.ibm.com>: >>> On Mon, 10 Jun 2013 22:40:24 +0900 >>> HATAYAMA Daisuke <d.hatayama@gmail.com> wrote: >>> >>>> 2013/6/8 Michael Holzheu <holzheu@linux.vnet.ibm.com>: <cut> > static int mmap_vmcore_fault(struct vm_area_struct *vma, struct'vm_fault *vmf) > { > struct address_space *mapping = vma->vm_private_data; > pgoff_t index = vmf->pgoff; > struct page *page; > loff_t src; > char *buf; > > page = find_or_create_page(mapping, index, GFP_KERNEL); > if (!page) > return VM_FAULT_OOM; > if (!PageUptodate(page)) { > src = index << PAGE_CACHE_SHIFT; > buf = (void *) (page_to_pfn(page) << PAGE_SHIFT); > if (__read_vmcore(buf, PAGE_SIZE, &src, 0) < 0) { > unlock_page(page); > return VM_FAULT_SIGBUS; > } > SetPageUptodate(page); > } > unlock_page(page); > vmf->page = page; > return 0; > } > > Perhaps one open issue remains: > > Can we remove the page from the page cache if __read_vmcore() fails? > Yes, use page_cache_release() after unlocking the page like: if (__read_vmcore(buf, PAGE_SIZE, &src, 0) < 0) { unlock_page(page); + page_cache_release(page); return VM_FAULT_SIGBUS; } BTW, you now keep file->f_mapping in vma->vm_private_data, but the vma already has the file object in its vma->vm_file member. You can get the mapping by vma->vm_file->f_mapping without necessity of vma->vm_private_data. -- Thanks. HATAYAMA, Daisuke _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec
next prev parent reply other threads:[~2013-06-13 1:33 UTC|newest] Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top 2013-06-07 16:55 [PATCH v5 0/5] kdump: Allow ELF header creation in new kernel Michael Holzheu 2013-06-07 16:55 ` Michael Holzheu 2013-06-07 16:55 ` [PATCH v5 1/5] vmcore: Introduce ELF header in new memory feature Michael Holzheu 2013-06-07 16:55 ` Michael Holzheu 2013-06-10 13:35 ` HATAYAMA Daisuke 2013-06-10 13:35 ` HATAYAMA Daisuke 2013-06-10 13:53 ` Michael Holzheu 2013-06-10 13:53 ` Michael Holzheu 2013-06-14 18:54 ` Vivek Goyal 2013-06-14 18:54 ` Vivek Goyal 2013-06-21 14:17 ` Michael Holzheu 2013-06-21 14:17 ` Michael Holzheu 2013-06-27 19:32 ` Vivek Goyal 2013-06-27 19:32 ` Vivek Goyal 2013-06-27 20:10 ` Cliff Wickman 2013-06-27 20:10 ` Cliff Wickman 2013-06-27 20:23 ` Vivek Goyal 2013-06-27 20:23 ` Vivek Goyal 2013-06-28 8:15 ` Michael Holzheu 2013-06-28 8:15 ` Michael Holzheu 2013-07-01 17:37 ` Vivek Goyal 2013-07-01 17:37 ` Vivek Goyal 2013-07-01 18:29 ` Michael Holzheu 2013-07-01 18:29 ` Michael Holzheu 2013-06-07 16:55 ` [PATCH v5 2/5] s390/vmcore: Use " Michael Holzheu 2013-06-07 16:55 ` Michael Holzheu 2013-06-10 13:36 ` HATAYAMA Daisuke 2013-06-10 13:36 ` HATAYAMA Daisuke 2013-06-10 13:48 ` Michael Holzheu 2013-06-10 13:48 ` Michael Holzheu 2013-06-14 19:16 ` Vivek Goyal 2013-06-14 19:16 ` Vivek Goyal 2013-06-07 16:55 ` [PATCH v5 3/5] vmcore: Introduce remap_oldmem_pfn_range() Michael Holzheu 2013-06-07 16:55 ` Michael Holzheu [not found] ` <CAJGZr0+_W0dp2f9VtVAiUT2fqiwe91gHXd9zYzfMMzBZSZogww@mail.gmail.com> 2013-06-10 8:00 ` Michael Holzheu 2013-06-10 8:00 ` Michael Holzheu 2013-06-10 13:40 ` HATAYAMA Daisuke 2013-06-10 13:40 ` HATAYAMA Daisuke 2013-06-10 14:03 ` Michael Holzheu 2013-06-10 14:03 ` Michael Holzheu 2013-06-10 15:37 ` Michael Holzheu 2013-06-10 15:37 ` Michael Holzheu 2013-06-11 12:42 ` HATAYAMA Daisuke 2013-06-11 12:42 ` HATAYAMA Daisuke 2013-06-12 9:13 ` Michael Holzheu 2013-06-12 9:13 ` Michael Holzheu 2013-06-13 1:32 ` HATAYAMA Daisuke [this message] 2013-06-13 1:32 ` HATAYAMA Daisuke 2013-06-13 8:54 ` Michael Holzheu 2013-06-13 8:54 ` Michael Holzheu 2013-06-13 4:00 ` HATAYAMA Daisuke 2013-06-13 4:00 ` HATAYAMA Daisuke 2013-06-11 13:20 ` HATAYAMA Daisuke 2013-06-11 13:20 ` HATAYAMA Daisuke 2013-06-07 16:56 ` [PATCH v5 4/5] s390/vmcore: Implement remap_oldmem_pfn_range for s390 Michael Holzheu 2013-06-07 16:56 ` Michael Holzheu 2013-06-14 20:08 ` Vivek Goyal 2013-06-14 20:08 ` Vivek Goyal 2013-06-07 16:56 ` [PATCH v5 5/5] s390/vmcore: Use vmcore for zfcpdump Michael Holzheu 2013-06-07 16:56 ` Michael Holzheu 2013-06-11 23:47 ` HATAYAMA Daisuke 2013-06-11 23:47 ` HATAYAMA Daisuke 2013-06-12 9:14 ` Michael Holzheu 2013-06-12 9:14 ` Michael Holzheu 2013-06-14 18:54 ` [PATCH v5 0/5] kdump: Allow ELF header creation in new kernel Vivek Goyal 2013-06-14 18:54 ` Vivek Goyal 2013-06-21 13:39 ` Michael Holzheu 2013-06-21 13:39 ` Michael Holzheu
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