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Sun, 1 Dec 2019 01:52:27 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D0A13208C3; Sun, 1 Dec 2019 01:52:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1575165146; bh=iQD54ihx+qYnzm6NaJOcT4d7GLAOB8UFHXUh5C1QGlw=; h=Date:From:To:Subject:From; b=QYdv3OzOia8626nHiFdgQNBUHjoIrD/96HATDVChnya3a52lTOt1W1AWEEVKnq5PY 5dB+q3nOPQTS6AWmKodIgOKG7FxWy5L1r/Bg+uU/y46r3HAKHMqZ2DcumApxHxa46O EsdqEhvUR3r/3u6JWzi9d5T4l1+lXJeW/ZqIt8uI= Date: Sat, 30 Nov 2019 17:52:24 -0800 From: akpm@linux-foundation.org To: akpm@linux-foundation.org, alex@ghiti.fr, aou@eecs.berkeley.edu, ard.biesheuvel@linaro.org, arnd@arndb.de, aryabinin@virtuozzo.com, benh@kernel.crashing.org, borntraeger@de.ibm.com, bp@alien8.de, catalin.marinas@arm.com, dave.hansen@linux.intel.com, dave.jiang@intel.com, davem@davemloft.net, dvyukov@google.com, glider@google.com, gor@linux.ibm.com, heiko.carstens@de.ibm.com, hpa@zytor.com, james.morse@arm.com, jhogan@kernel.org, kan.liang@linux.intel.com, linux-mm@kvack.org, linux@armlinux.org.uk, luto@kernel.org, mark.rutland@arm.com, mawilcox@microsoft.com, mingo@elte.hu, mm-commits@vger.kernel.org, mpe@ellerman.id.au, n-horiguchi@ah.jp.nec.com, palmer@sifive.com, paul.burton@mips.com, paul.walmsley@sifive.com, paulus@samba.org, peterz@infradead.org, ralf@linux-mips.org, shashim@codeaurora.org, steven.price@arm.com, tglx@linutronix.de, torvalds@linux-foundation.org, vgupta@synopsys.com, will@kernel.org, zong.li@sifive.com Subject: [patch 056/158] mm: pagewalk: add p4d_entry() and pgd_entry() Message-ID: <20191201015224.ZZwhTgzAI%akpm@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Steven Price Subject: mm: pagewalk: add p4d_entry() and pgd_entry() pgd_entry() and pud_entry() were removed by commit 0b1fbfe50006c410 ("mm/pagewalk: remove pgd_entry() and pud_entry()") because there were no users. We're about to add users so reintroduce them, along with p4d_entry() as we now have 5 levels of tables. Note that commit a00cc7d9dd93d66a ("mm, x86: add support for PUD-sized transparent hugepages") already re-added pud_entry() but with different semantics to the other callbacks. Since there have never been upstream users of this, revert the semantics back to match the other callbacks. This means pud_entry() is called for all entries, not just transparent huge pages. Link: http://lkml.kernel.org/r/20191028135910.33253-12-steven.price@arm.com Signed-off-by: Steven Price Tested-by: Zong Li Cc: Matthew Wilcox Cc: Dave Jiang Cc: Albert Ou Cc: Alexander Potapenko Cc: Alexandre Ghiti Cc: Andrey Ryabinin Cc: Andy Lutomirski Cc: Ard Biesheuvel Cc: Arnd Bergmann Cc: Benjamin Herrenschmidt Cc: Borislav Petkov Cc: Catalin Marinas Cc: Christian Borntraeger Cc: Dave Hansen Cc: David S. Miller Cc: Dmitry Vyukov Cc: Heiko Carstens Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: James Hogan Cc: James Morse Cc: "Liang, Kan" Cc: Mark Rutland Cc: Michael Ellerman Cc: Naoya Horiguchi Cc: Palmer Dabbelt Cc: Paul Burton Cc: Paul Mackerras Cc: Paul Walmsley Cc: Peter Zijlstra Cc: Ralf Baechle Cc: Russell King Cc: Shiraz Hashim Cc: Thomas Gleixner Cc: Vasily Gorbik Cc: Vineet Gupta Cc: Will Deacon Signed-off-by: Andrew Morton --- include/linux/pagewalk.h | 19 +++++++++++++------ mm/pagewalk.c | 27 ++++++++++++++++----------- 2 files changed, 29 insertions(+), 17 deletions(-) --- a/include/linux/pagewalk.h~mm-pagewalk-add-p4d_entry-and-pgd_entry +++ a/include/linux/pagewalk.h @@ -8,15 +8,15 @@ struct mm_walk; /** * mm_walk_ops - callbacks for walk_page_range - * @pud_entry: if set, called for each non-empty PUD (2nd-level) entry - * this handler should only handle pud_trans_huge() puds. - * the pmd_entry or pte_entry callbacks will be used for - * regular PUDs. - * @pmd_entry: if set, called for each non-empty PMD (3rd-level) entry + * @pgd_entry: if set, called for each non-empty PGD (top-level) entry + * @p4d_entry: if set, called for each non-empty P4D entry + * @pud_entry: if set, called for each non-empty PUD entry + * @pmd_entry: if set, called for each non-empty PMD entry * this handler is required to be able to handle * pmd_trans_huge() pmds. They may simply choose to * split_huge_page() instead of handling it explicitly. - * @pte_entry: if set, called for each non-empty PTE (4th-level) entry + * @pte_entry: if set, called for each non-empty PTE (lowest-level) + * entry * @pte_hole: if set, called for each hole at all levels * @hugetlb_entry: if set, called for each hugetlb entry * @test_walk: caller specific callback function to determine whether @@ -27,8 +27,15 @@ struct mm_walk; * @pre_vma: if set, called before starting walk on a non-null vma. * @post_vma: if set, called after a walk on a non-null vma, provided * that @pre_vma and the vma walk succeeded. + * + * p?d_entry callbacks are called even if those levels are folded on a + * particular architecture/configuration. */ struct mm_walk_ops { + int (*pgd_entry)(pgd_t *pgd, unsigned long addr, + unsigned long next, struct mm_walk *walk); + int (*p4d_entry)(p4d_t *p4d, unsigned long addr, + unsigned long next, struct mm_walk *walk); int (*pud_entry)(pud_t *pud, unsigned long addr, unsigned long next, struct mm_walk *walk); int (*pmd_entry)(pmd_t *pmd, unsigned long addr, --- a/mm/pagewalk.c~mm-pagewalk-add-p4d_entry-and-pgd_entry +++ a/mm/pagewalk.c @@ -94,15 +94,9 @@ static int walk_pud_range(p4d_t *p4d, un } if (ops->pud_entry) { - spinlock_t *ptl = pud_trans_huge_lock(pud, walk->vma); - - if (ptl) { - err = ops->pud_entry(pud, addr, next, walk); - spin_unlock(ptl); - if (err) - break; - continue; - } + err = ops->pud_entry(pud, addr, next, walk); + if (err) + break; } split_huge_pud(walk->vma, pud, addr); @@ -136,7 +130,12 @@ static int walk_p4d_range(pgd_t *pgd, un break; continue; } - if (ops->pmd_entry || ops->pte_entry) + if (ops->p4d_entry) { + err = ops->p4d_entry(p4d, addr, next, walk); + if (err) + break; + } + if (ops->pud_entry || ops->pmd_entry || ops->pte_entry) err = walk_pud_range(p4d, addr, next, walk); if (err) break; @@ -163,7 +162,13 @@ static int walk_pgd_range(unsigned long break; continue; } - if (ops->pmd_entry || ops->pte_entry) + if (ops->pgd_entry) { + err = ops->pgd_entry(pgd, addr, next, walk); + if (err) + break; + } + if (ops->p4d_entry || ops->pud_entry || ops->pmd_entry || + ops->pte_entry) err = walk_p4d_range(pgd, addr, next, walk); if (err) break;