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H A Dusx2yhwdeppcm.c1cdca61b Mon Nov 21 23:32:13 CST 2005 Hugh Dickins <hugh@veritas.com> [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>
1cdca61b Mon Nov 21 23:32:13 CST 2005 Hugh Dickins <hugh@veritas.com> [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>