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[172.10.233.147]) by smtp.gmail.com with ESMTPSA id w6-20020a0ded06000000b0056d2a19ad91sm2857020ywe.103.2023.06.15.16.02.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 15 Jun 2023 16:02:54 -0700 (PDT) Date: Thu, 15 Jun 2023 16:02:43 -0700 (PDT) From: Hugh Dickins X-X-Sender: hugh@ripple.attlocal.net To: Andrew Morton cc: Nathan Chancellor , Hugh Dickins , Mike Kravetz , Mike Rapoport , "Kirill A. Shutemov" , Matthew Wilcox , David Hildenbrand , Suren Baghdasaryan , Qi Zheng , Peter Zijlstra , Russell King , Catalin Marinas , Will Deacon , Geert Uytterhoeven , Greg Ungerer , Michal Simek , Thomas Bogendoerfer , Helge Deller , John David Anglin , "Aneesh Kumar K.V" , Michael Ellerman , Alexandre Ghiti , Palmer Dabbelt , Heiko Carstens , Christian Borntraeger , Claudio Imbrenda , Alexander Gordeev , John Paul Adrian Glaubitz , "David S. Miller" , Chris Zankel , Max Filippov , Yu Zhao , x86@kernel.org, linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH v2 07/23 replacement] mips: add pte_unmap() to balance pte_offset_map() In-Reply-To: <76b41825-30fa-b9e8-d043-2affcba24317@google.com> Message-ID: References: <178970b0-1539-8aac-76fd-972c6c46ec17@google.com> <20230614231758.GA1503611@dev-arch.thelio-3990X> <344a4da-3890-45fd-607e-b5f85ca6ad48@google.com> <20230615155059.GB3665766@dev-arch.thelio-3990X> <76b41825-30fa-b9e8-d043-2affcba24317@google.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-parisc@vger.kernel.org To keep balance in future, __update_tlb() remember to pte_unmap() after pte_offset_map(). This is an odd case, since the caller has already done pte_offset_map_lock(), then mips forgets the address and recalculates it; but my two naive attempts to clean that up did more harm than good. Tested-by: Nathan Chancellor Signed-off-by: Hugh Dickins --- Andrew, please replace my mips patch, and its build warning fix patch, in mm-unstable by this less ambitious but working replacement - thanks. arch/mips/mm/tlb-r4k.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/arch/mips/mm/tlb-r4k.c b/arch/mips/mm/tlb-r4k.c index 1b939abbe4ca..93c2d695588a 100644 --- a/arch/mips/mm/tlb-r4k.c +++ b/arch/mips/mm/tlb-r4k.c @@ -297,7 +297,7 @@ void __update_tlb(struct vm_area_struct * vma, unsigned long address, pte_t pte) p4d_t *p4dp; pud_t *pudp; pmd_t *pmdp; - pte_t *ptep; + pte_t *ptep, *ptemap = NULL; int idx, pid; /* @@ -344,7 +344,12 @@ void __update_tlb(struct vm_area_struct * vma, unsigned long address, pte_t pte) } else #endif { - ptep = pte_offset_map(pmdp, address); + ptemap = ptep = pte_offset_map(pmdp, address); + /* + * update_mmu_cache() is called between pte_offset_map_lock() + * and pte_unmap_unlock(), so we can assume that ptep is not + * NULL here: and what should be done below if it were NULL? + */ #if defined(CONFIG_PHYS_ADDR_T_64BIT) && defined(CONFIG_CPU_MIPS32) #ifdef CONFIG_XPA @@ -373,6 +378,9 @@ void __update_tlb(struct vm_area_struct * vma, unsigned long address, pte_t pte) tlbw_use_hazard(); htw_start(); flush_micro_tlb_vm(vma); + + if (ptemap) + pte_unmap(ptemap); local_irq_restore(flags); }