The param "start" actually referes to the physical memory start, which is to be mapped into virtual area vma. And it is the field vma->vm_start which stands for the start of the area. Most of the time, we do not read through whole implementation of a function but only the definition and essential comments. Accurate comments are definitely the base stone. Signed-off-by: Wang Wenhu <wenhu.wang@xxxxxxxx> --- mm/memory.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/memory.c b/mm/memory.c index 583f84519870..5c356a57b892 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2009,7 +2009,7 @@ EXPORT_SYMBOL(remap_pfn_range); /** * vm_iomap_memory - remap memory to userspace * @vma: user vma to map to - * @start: start of area + * @start: start of the physical memory to be mapped * @len: size of area * * This is a simplified io_remap_pfn_range() for common driver use. The -- 2.17.1