[PATCH 11/29] mm: only allow page table mappings for built-in zsmalloc
From: Christoph Hellwig <hch@lst.de>
Date: 2020-04-14 13:15:40
Also in:
bpf, linux-arch, linux-arm-kernel, linux-hyperv, linux-iommu, linux-mm, linux-s390, lkml
Subsystem:
memory management, memory management - core, the rest, vmalloc · Maintainers:
Andrew Morton, David Hildenbrand, Linus Torvalds, Uladzislau Rezki
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