Commit ac536a84 authored Oct 14, 2013 by Takashi Iwai

ALSA: us122l: Fix pcm_usb_stream mmapping regression



The pcm_usb_stream plugin requires the mremap explicitly for the read
buffer, as it expands itself once after reading the required size.
But the commit [314e51b9: mm: kill vma flag VM_RESERVED and
mm->reserved_vm counter] converted blindly to a combination of
VM_DONTEXPAND | VM_DONTDUMP like other normal drivers, and this
resulted in the failure of mremap().

For fixing this regression, we need to remove VM_DONTEXPAND for the
read-buffer mmap.

Reported-and-tested-by: James Miller <jamesstewartmiller@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

parent ccb04157

sound/usb/usx2y/us122l.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -262,7 +262,9 @@ static int usb_stream_hwdep_mmap(struct snd_hwdep *hw,
		}

		area->vm_ops = &usb_stream_hwdep_vm_ops;
		area->vm_flags \|= VM_DONTEXPAND \| VM_DONTDUMP;
		area->vm_flags \|= VM_DONTDUMP;
		if (!read)
		area->vm_flags \|= VM_DONTEXPAND;
		area->vm_private_data = us122l;
		atomic_inc(&us122l->mmap_count);
		out:

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