From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0342F7F7F7 for ; Fri, 26 Apr 2024 04:01:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714104063; cv=none; b=GrsobUoZWsLmrPMA6cYBMjnKsZqTidof6O7o8rcLPD0stUeeZQE2O2Ej9Uzl4UwxUtlDXf3ElTiZ6vkfJqYKH7NnzaPKxNmOr+wJSIjcgArGj+9ouPM5V6YFILAfJtqLoEDgY+8942gJJf9+PZWGCZhlZQU1dIFags9B/e1tKgY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714104063; c=relaxed/simple; bh=erZOg1t0uDxxaxe30HAYKYZ/zb1cC2vHU4MzRpmQL4U=; h=Date:To:From:Subject:Message-Id; b=iJQdECxdq4YzFUYyepB+aIj2vY5IP5BZBmvs1Ilsv+rFMs74C9qmCyer7Q9wnabImKwqWKfpwJaE43b+xDuRViqVZx6r/hzLqmCWgeiz8sixHcm5XGRL/NSxZgw6MmMXbut2IAyAgld3Zs2n/oRDw827b/yCMl5V0hpUnbbRtTU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=NUI1HRvJ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="NUI1HRvJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CD720C113CD; Fri, 26 Apr 2024 04:01:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1714104062; bh=erZOg1t0uDxxaxe30HAYKYZ/zb1cC2vHU4MzRpmQL4U=; h=Date:To:From:Subject:From; b=NUI1HRvJK7qeARp8OTaP6ObirIrTW/szlhB/HWzM115OeUSoyR5NGq+V9nv+swIGW 6PmPCVGS2FkSKhFjuoUY6ObnxB9fn/xJ24LfY7wjTBEnSA9+FI28IBQ0vRQzOS/GEU bdDSaramUUruQZRCEPw0tyrvRRPcI1m8MLi4QQPs= Date: Thu, 25 Apr 2024 21:01:02 -0700 To: mm-commits@vger.kernel.org,willy@infradead.org,vbabka@suse.cz,shy828301@gmail.com,ryan.roberts@arm.com,rppt@kernel.org,riel@surriel.com,muchun.song@linux.dev,mpe@ellerman.id.au,lstoakes@gmail.com,kirill@shutemov.name,jthoughton@google.com,jhubbard@nvidia.com,jgg@nvidia.com,hch@infradead.org,david@redhat.com,christophe.leroy@csgroup.eu,axelrasmussen@google.com,aneesh.kumar@kernel.org,andrew.jones@linux.dev,aarcange@redhat.com,peterx@redhat.com,akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-stable] mm-gup-cache-pudp-in-follow_pud_mask.patch removed from -mm tree Message-Id: <20240426040102.CD720C113CD@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: mm/gup: cache *pudp in follow_pud_mask() has been removed from the -mm tree. Its filename was mm-gup-cache-pudp-in-follow_pud_mask.patch This patch was dropped because it was merged into the mm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Peter Xu Subject: mm/gup: cache *pudp in follow_pud_mask() Date: Wed, 27 Mar 2024 11:23:28 -0400 Introduce "pud_t pud" in the function, so the code won't dereference *pudp multiple time. Not only because that looks less straightforward, but also because if the dereference really happened, it's not clear whether there can be race to see different *pudp values if it's being modified at the same time. Link: https://lkml.kernel.org/r/20240327152332.950956-10-peterx@redhat.com Signed-off-by: Peter Xu Acked-by: James Houghton Reviewed-by: Jason Gunthorpe Tested-by: Ryan Roberts Cc: Andrea Arcangeli Cc: Andrew Jones Cc: Aneesh Kumar K.V (IBM) Cc: Axel Rasmussen Cc: Christophe Leroy Cc: Christoph Hellwig Cc: David Hildenbrand Cc: John Hubbard Cc: Kirill A. Shutemov Cc: Lorenzo Stoakes Cc: Matthew Wilcox (Oracle) Cc: Michael Ellerman Cc: "Mike Rapoport (IBM)" Cc: Muchun Song Cc: Rik van Riel Cc: Vlastimil Babka Cc: Yang Shi Signed-off-by: Andrew Morton --- mm/gup.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) --- a/mm/gup.c~mm-gup-cache-pudp-in-follow_pud_mask +++ a/mm/gup.c @@ -753,26 +753,27 @@ static struct page *follow_pud_mask(stru unsigned int flags, struct follow_page_context *ctx) { - pud_t *pud; + pud_t *pudp, pud; spinlock_t *ptl; struct page *page; struct mm_struct *mm = vma->vm_mm; - pud = pud_offset(p4dp, address); - if (pud_none(*pud)) + pudp = pud_offset(p4dp, address); + pud = READ_ONCE(*pudp); + if (pud_none(pud)) return no_page_table(vma, flags, address); - if (pud_devmap(*pud)) { - ptl = pud_lock(mm, pud); - page = follow_devmap_pud(vma, address, pud, flags, &ctx->pgmap); + if (pud_devmap(pud)) { + ptl = pud_lock(mm, pudp); + page = follow_devmap_pud(vma, address, pudp, flags, &ctx->pgmap); spin_unlock(ptl); if (page) return page; return no_page_table(vma, flags, address); } - if (unlikely(pud_bad(*pud))) + if (unlikely(pud_bad(pud))) return no_page_table(vma, flags, address); - return follow_pmd_mask(vma, address, pud, flags, ctx); + return follow_pmd_mask(vma, address, pudp, flags, ctx); } static struct page *follow_p4d_mask(struct vm_area_struct *vma, _ Patches currently in -mm which might be from peterx@redhat.com are mm-userfaultfd-reset-ptes-when-close-for-wr-protected-ones.patch mm-hugetlb-assert-hugetlb_lock-in-__hugetlb_cgroup_commit_charge.patch mm-page_table_check-support-userfault-wr-protect-entries.patch