提交 1cdca61b 编写于 作者: H Hugh Dickins 提交者: Linus Torvalds

[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: NHugh Dickins <hugh@veritas.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
上级 83e9b7e9
......@@ -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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