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GET /api/patches/811774/?format=api
HTTP 200 OK
Allow: GET, PUT, PATCH, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "id": 811774,
    "url": "http://patchwork.ozlabs.org/api/patches/811774/?format=api",
    "web_url": "http://patchwork.ozlabs.org/project/linuxppc-dev/patch/1504894024-2750-2-git-send-email-ldufour@linux.vnet.ibm.com/",
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        "name": "Linux PPC development",
        "link_name": "linuxppc-dev",
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        "web_url": "https://github.com/linuxppc/wiki/wiki",
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        "webscm_url": "https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/",
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    "msgid": "<1504894024-2750-2-git-send-email-ldufour@linux.vnet.ibm.com>",
    "list_archive_url": "https://lore.kernel.org/linuxppc-dev/1504894024-2750-2-git-send-email-ldufour@linux.vnet.ibm.com/",
    "date": "2017-09-08T18:06:45",
    "name": "[v3,01/20] mm: Dont assume page-table invariance during faults",
    "commit_ref": null,
    "pull_url": null,
    "state": "not-applicable",
    "archived": false,
    "hash": "eb65d4396c0e5116177125787cbcb65cb19321e7",
    "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/1504894024-2750-2-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/811774/comments/",
    "check": "pending",
    "checks": "http://patchwork.ozlabs.org/api/patches/811774/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 01/20] mm: Dont assume page-table invariance during faults",
        "Date": "Fri,  8 Sep 2017 20:06:45 +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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        "Precedence": "list",
        "List-Id": "Linux on PowerPC Developers Mail List\n\t<linuxppc-dev.lists.ozlabs.org>",
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        "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": "From: Peter Zijlstra <peterz@infradead.org>\n\nOne of the side effects of speculating on faults (without holding\nmmap_sem) is that we can race with free_pgtables() and therefore we\ncannot assume the page-tables will stick around.\n\nRemove the reliance on the pte pointer.\n\nSigned-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>\n---\n mm/memory.c | 29 -----------------------------\n 1 file changed, 29 deletions(-)",
    "diff": "diff --git a/mm/memory.c b/mm/memory.c\nindex ec4e15494901..30bccfa00630 100644\n--- a/mm/memory.c\n+++ b/mm/memory.c\n@@ -2270,30 +2270,6 @@ int apply_to_page_range(struct mm_struct *mm, unsigned long addr,\n }\n EXPORT_SYMBOL_GPL(apply_to_page_range);\n \n-/*\n- * handle_pte_fault chooses page fault handler according to an entry which was\n- * read non-atomically.  Before making any commitment, on those architectures\n- * or configurations (e.g. i386 with PAE) which might give a mix of unmatched\n- * parts, do_swap_page must check under lock before unmapping the pte and\n- * proceeding (but do_wp_page is only called after already making such a check;\n- * and do_anonymous_page can safely check later on).\n- */\n-static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd,\n-\t\t\t\tpte_t *page_table, pte_t orig_pte)\n-{\n-\tint same = 1;\n-#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)\n-\tif (sizeof(pte_t) > sizeof(unsigned long)) {\n-\t\tspinlock_t *ptl = pte_lockptr(mm, pmd);\n-\t\tspin_lock(ptl);\n-\t\tsame = pte_same(*page_table, orig_pte);\n-\t\tspin_unlock(ptl);\n-\t}\n-#endif\n-\tpte_unmap(page_table);\n-\treturn same;\n-}\n-\n static inline void cow_user_page(struct page *dst, struct page *src, unsigned long va, struct vm_area_struct *vma)\n {\n \tdebug_dma_assert_idle(src);\n@@ -2854,11 +2830,6 @@ int do_swap_page(struct vm_fault *vmf)\n \n \tif (vma_readahead)\n \t\tpage = swap_readahead_detect(vmf, &swap_ra);\n-\tif (!pte_unmap_same(vma->vm_mm, vmf->pmd, vmf->pte, vmf->orig_pte)) {\n-\t\tif (page)\n-\t\t\tput_page(page);\n-\t\tgoto out;\n-\t}\n \n \tentry = pte_to_swp_entry(vmf->orig_pte);\n \tif (unlikely(non_swap_entry(entry))) {\n",
    "prefixes": [
        "v3",
        "01/20"
    ]
}