Commit 1cdca61b authored Nov 21, 2005 by Hugh Dickins Committed by Linus Torvalds Nov 22, 2005

[PATCH] unpaged: sound nopage get_page

Something noticed when studying use of VM_RESERVED in different drivers:
snd_usX2Y_hwdep_pcm_vm_nopage omitted to get_page: fixed.

And how did this work before? Aargh! That nopage is returning a page from
within a buffer allocated by snd_malloc_pages, which allocates a high-order
page, then does SetPageReserved on each 0-order page within.

That would have worked in 2.6.14, because when the area was unmapped,
PageReserved inhibited put_page. 2.6.15-rc1 removed that inhibition (while
leaving ineffective PageReserveds around for now), but it hasn't caused
trouble because.. we've not been freeing from VM_RESERVED at all.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

parent 83e9b7e9

sound/usb/usx2y/usx2yhwdeppcm.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -691,6 +691,7 @@ static struct page * snd_usX2Y_hwdep_pcm_vm_nopage(struct vm_area_struct *area,
		snd_assert((offset % PAGE_SIZE) == 0, return NOPAGE_OOM);
		vaddr = (char)((usX2Ydev_t)area->vm_private_data)->hwdep_pcm_shm + offset;
		page = virt_to_page(vaddr);
		get_page(page);

		if (type)
		*type = VM_FAULT_MINOR;

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