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[172.10.233.147]) by smtp.gmail.com with ESMTPSA id h6-20020a258a86000000b00b9a80b9e08esm3435393ybl.12.2023.05.09.21.52.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 09 May 2023 21:52:35 -0700 (PDT) Date: Tue, 9 May 2023 21:52:31 -0700 (PDT) From: Hugh Dickins X-X-Sender: hugh@ripple.attlocal.net To: Andrew Morton cc: Mike Kravetz , Mike Rapoport , "Kirill A. Shutemov" , Matthew Wilcox , David Hildenbrand , Suren Baghdasaryan , Qi Zheng , 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 , John Paul Adrian Glaubitz , "David S. Miller" , Chris Zankel , Max Filippov , 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 08/23] parisc: add pte_unmap() to balance get_ptep() In-Reply-To: <77a5d8c-406b-7068-4f17-23b7ac53bc83@google.com> Message-ID: <44ebbf90-5fbb-2815-17c7-fcfe3c87d78e@google.com> References: <77a5d8c-406b-7068-4f17-23b7ac53bc83@google.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230509_215236_860187_9035889E X-CRM114-Status: GOOD ( 17.56 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org To keep balance in future, remember to pte_unmap() after a successful get_ptep(). And (we might as well) pretend that flush_cache_pages() really needed a map there, to read the pfn before "unmapping". Signed-off-by: Hugh Dickins --- arch/parisc/kernel/cache.c | 26 +++++++++++++++++++++----- 1 file changed, 21 insertions(+), 5 deletions(-) diff --git a/arch/parisc/kernel/cache.c b/arch/parisc/kernel/cache.c index 1d3b8bc8a623..b0c969b3a300 100644 --- a/arch/parisc/kernel/cache.c +++ b/arch/parisc/kernel/cache.c @@ -425,10 +425,15 @@ void flush_dcache_page(struct page *page) offset = (pgoff - mpnt->vm_pgoff) << PAGE_SHIFT; addr = mpnt->vm_start + offset; if (parisc_requires_coherency()) { + bool needs_flush = false; pte_t *ptep; ptep = get_ptep(mpnt->vm_mm, addr); - if (ptep && pte_needs_flush(*ptep)) + if (ptep) { + needs_flush = pte_needs_flush(*ptep); + pte_unmap(ptep); + } + if (needs_flush) flush_user_cache_page(mpnt, addr); } else { /* @@ -560,14 +565,20 @@ EXPORT_SYMBOL(flush_kernel_dcache_page_addr); static void flush_cache_page_if_present(struct vm_area_struct *vma, unsigned long vmaddr, unsigned long pfn) { - pte_t *ptep = get_ptep(vma->vm_mm, vmaddr); + bool needs_flush = false; + pte_t *ptep; /* * The pte check is racy and sometimes the flush will trigger * a non-access TLB miss. Hopefully, the page has already been * flushed. */ - if (ptep && pte_needs_flush(*ptep)) + ptep = get_ptep(vma->vm_mm, vmaddr); + if (ptep) { + needs_flush = pte_needs_flush(*ptep)) + pte_unmap(ptep); + } + if (needs_flush) flush_cache_page(vma, vmaddr, pfn); } @@ -634,17 +645,22 @@ static void flush_cache_pages(struct vm_area_struct *vma, unsigned long start, u pte_t *ptep; for (addr = start; addr < end; addr += PAGE_SIZE) { + bool needs_flush = false; /* * The vma can contain pages that aren't present. Although * the pte search is expensive, we need the pte to find the * page pfn and to check whether the page should be flushed. */ ptep = get_ptep(vma->vm_mm, addr); - if (ptep && pte_needs_flush(*ptep)) { + if (ptep) { + needs_flush = pte_needs_flush(*ptep); + pfn = pte_pfn(*ptep); + pte_unmap(ptep); + } + if (needs_flush) { if (parisc_requires_coherency()) { flush_user_cache_page(vma, addr); } else { - pfn = pte_pfn(*ptep); if (WARN_ON(!pfn_valid(pfn))) return; __flush_cache_page(vma, addr, PFN_PHYS(pfn));