diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index 77ba50ddcf9e346f799b2c099abfec5694921afb..d18b3982548b161c90704a255327422cbb6ab347 100644
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -3422,7 +3422,7 @@ int snd_pcm_lib_default_mmap(struct snd_pcm_substream *substream,
 					 area,
 					 substream->runtime->dma_area,
 					 substream->runtime->dma_addr,
-					 area->vm_end - area->vm_start);
+					 substream->runtime->dma_bytes);
 #endif /* CONFIG_X86 */
 	/* mmap with fault handler */
 	area->vm_ops = &snd_pcm_vm_ops_data_fault;