Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Christoph Hellwig <hch@lst.de>
To:     Andrew Morton <akpm@linux-foundation.org>,
        "K. Y. Srinivasan" <kys@microsoft.com>,
        Haiyang Zhang <haiyangz@microsoft.com>,
        Stephen Hemminger <sthemmin@microsoft.com>,
        Wei Liu <wei.liu@kernel.org>, x86@kernel.org,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        Laura Abbott <labbott@redhat.com>,
        Sumit Semwal <sumit.semwal@linaro.org>,
        Sakari Ailus <sakari.ailus@linux.intel.com>,
        Minchan Kim <minchan@kernel.org>,
        Nitin Gupta <ngupta@vflare.org>
Cc:     Robin Murphy <robin.murphy@arm.com>,
        Christophe Leroy <christophe.leroy@c-s.fr>,
        Peter Zijlstra <peterz@infradead.org>,
        linuxppc-dev@lists.ozlabs.org, linux-hyperv@vger.kernel.org,
        dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org,
        linux-arch@vger.kernel.org, linux-mm@kvack.org,
        iommu@lists.linux-foundation.org,
        linux-arm-kernel@lists.infradead.org, linux-s390@vger.kernel.org,
        bpf@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 11/29] mm: only allow page table mappings for built-in zsmalloc
Date:   Tue, 14 Apr 2020 15:13:30 +0200
Message-Id: <20200414131348.444715-12-hch@lst.de>
In-Reply-To: <20200414131348.444715-1-hch@lst.de>
References: <20200414131348.444715-1-hch@lst.de>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

This allows to unexport map_vm_area and unmap_kernel_range, which are
rather deep internal and should not be available to modules, as they for
example allow fine grained control of mapping permissions, and also
allow splitting the setup of a vmalloc area and the actual mapping and
thus expose vmalloc internals.

zsmalloc is typically built-in and continues to work (just like the
percpu-vm code using a similar patter), while modular zsmalloc also
continues to work, but must use copies.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 mm/Kconfig   | 2 +-
 mm/vmalloc.c | 2 --
 2 files changed, 1 insertion(+), 3 deletions(-)

diff --git a/mm/Kconfig b/mm/Kconfig
index 09a9edfb8461..5c0362bd8d56 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -707,7 +707,7 @@ config ZSMALLOC
 
 config ZSMALLOC_PGTABLE_MAPPING
 	bool "Use page table mapping to access object in zsmalloc"
-	depends on ZSMALLOC
+	depends on ZSMALLOC=y
 	help
 	  By default, zsmalloc uses a copy-based object mapping method to
 	  access allocations that span two pages. However, if a particular
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 3375f9508ef6..9183fc0d365a 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -2046,7 +2046,6 @@ void unmap_kernel_range(unsigned long addr, unsigned long size)
 	vunmap_page_range(addr, end);
 	flush_tlb_kernel_range(addr, end);
 }
-EXPORT_SYMBOL_GPL(unmap_kernel_range);
 
 int map_vm_area(struct vm_struct *area, pgprot_t prot, struct page **pages)
 {
@@ -2058,7 +2057,6 @@ int map_vm_area(struct vm_struct *area, pgprot_t prot, struct page **pages)
 
 	return err > 0 ? 0 : err;
 }
-EXPORT_SYMBOL_GPL(map_vm_area);
 
 static inline void setup_vmalloc_vm_locked(struct vm_struct *vm,
 	struct vmap_area *va, unsigned long flags, const void *caller)
-- 
2.25.1