ALSA: pcm - Safer boundary checks

Make the boundary checks a bit safer.
These caese are rare or theoretically won't happen, but nothing
bad to keep the checks safer...

Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c
index 063c675177a9dc53f12c84a0c297e20b48d5127b..fbb2e391591ea2c1a5e1933c65f6b946e7a0bd2c 100644 (file)
--- a/sound/core/pcm_lib.c
+++ b/sound/core/pcm_lib.c
@@ -222,8 +222,9 @@ static int snd_pcm_update_hw_ptr_interrupt(struct snd_pcm_substream *substream)
        hw_ptr_interrupt = runtime->hw_ptr_interrupt + runtime->period_size;
        delta = new_hw_ptr - hw_ptr_interrupt;
        if (hw_ptr_interrupt >= runtime->boundary) {
-               hw_ptr_interrupt %= runtime->boundary;
-               if (!hw_base) /* hw_base was already lapped; recalc delta */
+               hw_ptr_interrupt -= runtime->boundary;
+               if (hw_base < runtime->boundary / 2)
+                       /* hw_base was already lapped; recalc delta */
                        delta = new_hw_ptr - hw_ptr_interrupt;
        }
        if (delta < 0) {
@@ -241,7 +242,7 @@ static int snd_pcm_update_hw_ptr_interrupt(struct snd_pcm_substream *substream)
                        delta = 0;
                } else {
                        hw_base += runtime->buffer_size;
-                       if (hw_base == runtime->boundary)
+                       if (hw_base >= runtime->boundary)
                                hw_base = 0;
                        new_hw_ptr = hw_base + pos;
                }
@@ -296,7 +297,7 @@ int snd_pcm_update_hw_ptr(struct snd_pcm_substream *substream)
                        return 0;
                }
                hw_base += runtime->buffer_size;
-               if (hw_base == runtime->boundary)
+               if (hw_base >= runtime->boundary)
                        hw_base = 0;
                new_hw_ptr = hw_base + pos;
        }