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GET /api/patches/811796/?format=api
HTTP 200 OK
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{
    "id": 811796,
    "url": "http://patchwork.ozlabs.org/api/patches/811796/?format=api",
    "web_url": "http://patchwork.ozlabs.org/project/linuxppc-dev/patch/1504894024-2750-12-git-send-email-ldufour@linux.vnet.ibm.com/",
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        "url": "http://patchwork.ozlabs.org/api/projects/2/?format=api",
        "name": "Linux PPC development",
        "link_name": "linuxppc-dev",
        "list_id": "linuxppc-dev.lists.ozlabs.org",
        "list_email": "linuxppc-dev@lists.ozlabs.org",
        "web_url": "https://github.com/linuxppc/wiki/wiki",
        "scm_url": "https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git",
        "webscm_url": "https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/",
        "list_archive_url": "https://lore.kernel.org/linuxppc-dev/",
        "list_archive_url_format": "https://lore.kernel.org/linuxppc-dev/{}/",
        "commit_url_format": "https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/commit/?id={}"
    },
    "msgid": "<1504894024-2750-12-git-send-email-ldufour@linux.vnet.ibm.com>",
    "list_archive_url": "https://lore.kernel.org/linuxppc-dev/1504894024-2750-12-git-send-email-ldufour@linux.vnet.ibm.com/",
    "date": "2017-09-08T18:06:55",
    "name": "[v3,11/20] mm: Introduce __maybe_mkwrite()",
    "commit_ref": null,
    "pull_url": null,
    "state": "not-applicable",
    "archived": false,
    "hash": "fee351a4f4c7718d35d620c676bd37751feb5db2",
    "submitter": {
        "id": 40248,
        "url": "http://patchwork.ozlabs.org/api/people/40248/?format=api",
        "name": "Laurent Dufour",
        "email": "ldufour@linux.vnet.ibm.com"
    },
    "delegate": null,
    "mbox": "http://patchwork.ozlabs.org/project/linuxppc-dev/patch/1504894024-2750-12-git-send-email-ldufour@linux.vnet.ibm.com/mbox/",
    "series": [
        {
            "id": 2269,
            "url": "http://patchwork.ozlabs.org/api/series/2269/?format=api",
            "web_url": "http://patchwork.ozlabs.org/project/linuxppc-dev/list/?series=2269",
            "date": "2017-09-08T18:06:44",
            "name": "Speculative page faults",
            "version": 3,
            "mbox": "http://patchwork.ozlabs.org/series/2269/mbox/"
        }
    ],
    "comments": "http://patchwork.ozlabs.org/api/patches/811796/comments/",
    "check": "pending",
    "checks": "http://patchwork.ozlabs.org/api/patches/811796/checks/",
    "tags": {},
    "related": [],
    "headers": {
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        ],
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        "From": "Laurent Dufour <ldufour@linux.vnet.ibm.com>",
        "To": "paulmck@linux.vnet.ibm.com, peterz@infradead.org,\n\takpm@linux-foundation.org, kirill@shutemov.name, ak@linux.intel.com, \n\tmhocko@kernel.org, dave@stgolabs.net, jack@suse.cz,\n\tMatthew Wilcox <willy@infradead.org>, benh@kernel.crashing.org,\n\tmpe@ellerman.id.au, paulus@samba.org,\n\tThomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>, \n\thpa@zytor.com, Will Deacon <will.deacon@arm.com>,\n\tSergey Senozhatsky <sergey.senozhatsky@gmail.com>",
        "Subject": "[PATCH v3 11/20] mm: Introduce __maybe_mkwrite()",
        "Date": "Fri,  8 Sep 2017 20:06:55 +0200",
        "X-Mailer": "git-send-email 2.7.4",
        "In-Reply-To": "<1504894024-2750-1-git-send-email-ldufour@linux.vnet.ibm.com>",
        "References": "<1504894024-2750-1-git-send-email-ldufour@linux.vnet.ibm.com>",
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        "Message-Id": "<1504894024-2750-12-git-send-email-ldufour@linux.vnet.ibm.com>",
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        "X-BeenThere": "linuxppc-dev@lists.ozlabs.org",
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        "Precedence": "list",
        "List-Id": "Linux on PowerPC Developers Mail List\n\t<linuxppc-dev.lists.ozlabs.org>",
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        "List-Subscribe": "<https://lists.ozlabs.org/listinfo/linuxppc-dev>,\n\t<mailto:linuxppc-dev-request@lists.ozlabs.org?subject=subscribe>",
        "Cc": "linuxppc-dev@lists.ozlabs.org, x86@kernel.org,\n\tlinux-kernel@vger.kernel.org, npiggin@gmail.com, linux-mm@kvack.org,\n\tTim Chen <tim.c.chen@linux.intel.com>, \n\tharen@linux.vnet.ibm.com, khandual@linux.vnet.ibm.com",
        "Errors-To": "linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org",
        "Sender": "\"Linuxppc-dev\"\n\t<linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org>"
    },
    "content": "The current maybe_mkwrite() is getting passed the pointer to the vma\nstructure to fetch the vm_flags field.\n\nWhen dealing with the speculative page fault handler, it will be better to\nrely on the cached vm_flags value stored in the vm_fault structure.\n\nThis patch introduce a __maybe_mkwrite() service which can be called by\npassing the value of the vm_flags field.\n\nThere is no change functional changes expected for the other callers of\nmaybe_mkwrite().\n\nSigned-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>\n---\n include/linux/mm.h | 9 +++++++--\n mm/memory.c        | 6 +++---\n 2 files changed, 10 insertions(+), 5 deletions(-)",
    "diff": "diff --git a/include/linux/mm.h b/include/linux/mm.h\nindex 5fd90ac31317..bb0c87f1c725 100644\n--- a/include/linux/mm.h\n+++ b/include/linux/mm.h\n@@ -673,13 +673,18 @@ void free_compound_page(struct page *page);\n  * pte_mkwrite.  But get_user_pages can cause write faults for mappings\n  * that do not have writing enabled, when used by access_process_vm.\n  */\n-static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)\n+static inline pte_t __maybe_mkwrite(pte_t pte, unsigned long vma_flags)\n {\n-\tif (likely(vma->vm_flags & VM_WRITE))\n+\tif (likely(vma_flags & VM_WRITE))\n \t\tpte = pte_mkwrite(pte);\n \treturn pte;\n }\n \n+static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)\n+{\n+\treturn __maybe_mkwrite(pte, vma->vm_flags);\n+}\n+\n int alloc_set_pte(struct vm_fault *vmf, struct mem_cgroup *memcg,\n \t\tstruct page *page);\n int finish_fault(struct vm_fault *vmf);\ndiff --git a/mm/memory.c b/mm/memory.c\nindex 4583f354be94..c306f1f64c9e 100644\n--- a/mm/memory.c\n+++ b/mm/memory.c\n@@ -2408,7 +2408,7 @@ static inline void wp_page_reuse(struct vm_fault *vmf)\n \n \tflush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte));\n \tentry = pte_mkyoung(vmf->orig_pte);\n-\tentry = maybe_mkwrite(pte_mkdirty(entry), vma);\n+\tentry = __maybe_mkwrite(pte_mkdirty(entry), vmf->vma_flags);\n \tif (ptep_set_access_flags(vma, vmf->address, vmf->pte, entry, 1))\n \t\tupdate_mmu_cache(vma, vmf->address, vmf->pte);\n \tpte_unmap_unlock(vmf->pte, vmf->ptl);\n@@ -2498,8 +2498,8 @@ static int wp_page_copy(struct vm_fault *vmf)\n \t\t\tinc_mm_counter_fast(mm, MM_ANONPAGES);\n \t\t}\n \t\tflush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte));\n-\t\tentry = mk_pte(new_page, vma->vm_page_prot);\n-\t\tentry = maybe_mkwrite(pte_mkdirty(entry), vma);\n+\t\tentry = mk_pte(new_page, vmf->vma_page_prot);\n+\t\tentry = __maybe_mkwrite(pte_mkdirty(entry), vmf->vma_flags);\n \t\t/*\n \t\t * Clear the pte entry and flush it first, before updating the\n \t\t * pte with the new entry. This will avoid a race condition\n",
    "prefixes": [
        "v3",
        "11/20"
    ]
}