Allocate and free vmalloc areas (5f4352fb) · Commits · 戴 / test

include/linux/vmalloc.h

+4 −0

Original line number	Diff line number	Diff line
		@@ -70,6 +70,10 @@ extern int map_vm_area(struct vm_struct *area, pgprot_t prot,
		struct page ***pages);
		extern void unmap_kernel_range(unsigned long addr, unsigned long size);

		/* Allocate/destroy a 'vmalloc' VM area. */
		extern struct vm_struct *alloc_vm_area(size_t size);
		extern void free_vm_area(struct vm_struct *area);

		/*
		* Internals. Dont't use..
		*/

+53 −0

Original line number	Diff line number	Diff line
		@@ -767,3 +767,56 @@ EXPORT_SYMBOL(remap_vmalloc_range);
		void __attribute__((weak)) vmalloc_sync_all(void)
		{
		}


		static int f(pte_t pte, struct page pmd_page, unsigned long addr, void *data)
		{
		/* apply_to_page_range() does all the hard work. */
		return 0;
		}

		/**
		* alloc_vm_area - allocate a range of kernel address space
		* @size: size of the area
		* @returns: NULL on failure, vm_struct on success
		*
		* This function reserves a range of kernel address space, and
		* allocates pagetables to map that range. No actual mappings
		* are created. If the kernel address space is not shared
		* between processes, it syncs the pagetable across all
		* processes.
		*/
		struct vm_struct *alloc_vm_area(size_t size)
		{
		struct vm_struct *area;

		area = get_vm_area(size, VM_IOREMAP);
		if (area == NULL)
		return NULL;

		/*
		* This ensures that page tables are constructed for this region
		* of kernel virtual address space and mapped into init_mm.
		*/
		if (apply_to_page_range(&init_mm, (unsigned long)area->addr,
		area->size, f, NULL)) {
		free_vm_area(area);
		return NULL;
		}

		/* Make sure the pagetables are constructed in process kernel
		mappings */
		vmalloc_sync_all();

		return area;
		}
		EXPORT_SYMBOL_GPL(alloc_vm_area);

		void free_vm_area(struct vm_struct *area)
		{
		struct vm_struct *ret;
		ret = remove_vm_area(area->addr);
		BUG_ON(ret != area);
		kfree(area);
		}
		EXPORT_SYMBOL_GPL(free_vm_area);