mm/vmalloc: interchage the implementation of vmalloc_to_{pfn,page} (ece86e22) · Commits · 戴 / test

Currently we are implementing vmalloc_to_pfn() as a wrapper around vmalloc_to_page(), which is implemented as follow: 1. walks the page talbes to generates the corresponding pfn, 2. then converts the pfn to struct page, 3. returns it. And vmalloc_to_pfn() re-wraps vmalloc_to_page() to get the pfn. This seems too circuitous, so this patch reverses the way: implement vmalloc_to_page() as a wrapper around vmalloc_to_pfn(). This makes vmalloc_to_pfn() and vmalloc_to_page() slightly more efficient. No functional change. Signed-off-by:

Jianyu Zhan <nasa4836@gmail.com> Cc: Vladimir Murzin <murzin.v@gmail.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

mm/vmalloc.c

+10 −10

Original line number	Diff line number	Diff line
		@@ -220,12 +220,12 @@ int is_vmalloc_or_module_addr(const void *x)
		}

		/*
		* Walk a vmap address to the struct page it maps.
		* Walk a vmap address to the physical pfn it maps to.
		*/
		struct page vmalloc_to_page(const void vmalloc_addr)
		unsigned long vmalloc_to_pfn(const void *vmalloc_addr)
		{
		unsigned long addr = (unsigned long) vmalloc_addr;
		struct page *page = NULL;
		unsigned long pfn = 0;
		pgd_t *pgd = pgd_offset_k(addr);

		/*
		@@ -244,23 +244,23 @@ struct page vmalloc_to_page(const void vmalloc_addr)
		ptep = pte_offset_map(pmd, addr);
		pte = *ptep;
		if (pte_present(pte))
		page = pte_page(pte);
		pfn = pte_pfn(pte);
		pte_unmap(ptep);
		}
		}
		}
		return page;
		return pfn;
		}
		EXPORT_SYMBOL(vmalloc_to_page);
		EXPORT_SYMBOL(vmalloc_to_pfn);

		/*
		* Map a vmalloc()-space virtual address to the physical page frame number.
		* Map a vmalloc()-space virtual address to the struct page.
		*/
		unsigned long vmalloc_to_pfn(const void *vmalloc_addr)
		struct page vmalloc_to_page(const void vmalloc_addr)
		{
		return page_to_pfn(vmalloc_to_page(vmalloc_addr));
		return pfn_to_page(vmalloc_to_pfn(vmalloc_addr));
		}
		EXPORT_SYMBOL(vmalloc_to_pfn);
		EXPORT_SYMBOL(vmalloc_to_page);


		/* Global kva allocator */

Admin message