ALSA: Allocate larger pages in sgbuf

[linux-2.6-omap-h63xx.git] / drivers / net / cassini.c

diff --git a/drivers/net/cassini.c b/drivers/net/cassini.c
index 83768df27806be9394fb087acac83ee6f87f08a0..f1936d51b458e387e3ba0ffef867f1e388bb8a90 100644 (file)
--- a/drivers/net/cassini.c
+++ b/drivers/net/cassini.c
@@ -576,6 +576,18 @@ static void cas_spare_recover(struct cas *cp, const gfp_t flags)
        list_for_each_safe(elem, tmp, &list) {
                cas_page_t *page = list_entry(elem, cas_page_t, list);
 
+               /*
+                * With the lockless pagecache, cassini buffering scheme gets
+                * slightly less accurate: we might find that a page has an
+                * elevated reference count here, due to a speculative ref,
+                * and skip it as in-use. Ideally we would be able to reclaim
+                * it. However this would be such a rare case, it doesn't
+                * matter too much as we should pick it up the next time round.
+                *
+                * Importantly, if we find that the page has a refcount of 1
+                * here (our refcount), then we know it is definitely not inuse
+                * so we can reuse it.
+                */
                if (page_count(page->buffer) > 1)
                        continue;