copy_from/to_iter() returns the actually copied bytes, and the more correct check should be to compare with the given bytes, instead of zero-check.

Fixes: cf393babb37a ("ALSA: pcm: Add copy ops with iov_iter") Reported-by: Al Viro viro@zeniv.linux.org.uk Closes: https://lore.kernel.org/r/20230902053044.GJ3390869@ZenIV Signed-off-by: Takashi Iwai tiwai@suse.de --- sound/core/pcm_lib.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c index 4859fb1caec9..a11cd7d6295f 100644 --- a/sound/core/pcm_lib.c +++ b/sound/core/pcm_lib.c @@ -1992,8 +1992,8 @@ static int default_write_copy(struct snd_pcm_substream *substream, int channel, unsigned long hwoff, struct iov_iter *iter, unsigned long bytes) { - if (!copy_from_iter(get_dma_ptr(substream->runtime, channel, hwoff), - bytes, iter)) + if (copy_from_iter(get_dma_ptr(substream->runtime, channel, hwoff), + bytes, iter) != bytes) return -EFAULT; return 0; } @@ -2025,8 +2025,8 @@ static int default_read_copy(struct snd_pcm_substream *substream, int channel, unsigned long hwoff, struct iov_iter *iter, unsigned long bytes) { - if (!copy_to_iter(get_dma_ptr(substream->runtime, channel, hwoff), - bytes, iter)) + if (copy_to_iter(get_dma_ptr(substream->runtime, channel, hwoff), + bytes, iter) != bytes) return -EFAULT; return 0; }