[PATCH] unpaged: fix sound Bad page states

Earlier I unifdefed PageCompound, so that snd_pcm_mmap_control_nopage and
others can give out a 0-order component of a higher-order page, which won't
be mistakenly freed when zap_pte_range unmaps it.  But many Bad page states
reported a PG_reserved was freed after all: I had missed that we need to
say __GFP_COMP to get compound page behaviour.

Some of these higher-order pages are allocated by snd_malloc_pages, some by
snd_malloc_dev_pages; or if SBUS, by sbus_alloc_consistent - but that has
no gfp arg, so add __GFP_COMP into its sparc32/64 implementations.

I'm still rather puzzled that DRM seems not to need a similar change.

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

1 files changed, 2 insertions, 0 deletions

diff --git a/sound/core/memalloc.c b/sound/core/memalloc.c
index 129abab5ce98..e4b8959dd4bb 100644
--- a/sound/core/memalloc.c
+++ b/sound/core/memalloc.c
@@ -197,6 +197,7 @@ void *snd_malloc_pages(size_t size, gfp_t gfp_flags)
 
         snd_assert(size > 0, return NULL);
         snd_assert(gfp_flags != 0, return NULL);
+        gfp_flags |= __GFP_COMP;        /* compound page lets parts be mapped */
         pg = get_order(size);
         if ((res = (void *) __get_free_pages(gfp_flags, pg)) != NULL) {
                 mark_pages(virt_to_page(res), pg);
@@ -241,6 +242,7 @@ static void *snd_malloc_dev_pages(struct device *dev, size_t size, dma_addr_t *d
         snd_assert(dma != NULL, return NULL);
         pg = get_order(size);
         gfp_flags = GFP_KERNEL
+                | __GFP_COMP    /* compound page lets parts be mapped */
                 | __GFP_NORETRY /* don't trigger OOM-killer */
                 | __GFP_NOWARN; /* no stack trace print - this call is non-critical */
         res = dma_alloc_coherent(dev, PAGE_SIZE << pg, dma, gfp_flags);