This patch might be useful for filesystems which implement read 
without help of generic_file_read. It EXPORT_SYMBOL-s page_cache_readahead and
handle_ra_miss.

Signed-off-by: Andrew Morton <akpm@osdl.org>
---

diff -puN mm/readahead.c~reiser4-export-page_cache_readahead mm/readahead.c


 mm/readahead.c |    2 ++
 1 files changed, 2 insertions(+)

diff -puN mm/readahead.c~reiser4-export-page_cache_readahead mm/readahead.c
--- linux-2.6.12-rc5-mm2/mm/readahead.c~reiser4-export-page_cache_readahead	2005-06-03 15:12:33.611538554 +0400
+++ linux-2.6.12-rc5-mm2-vs/mm/readahead.c	2005-06-03 15:13:45.040081677 +0400
@@ -526,6 +526,7 @@ page_cache_readahead(struct address_spac
 out:
 	return ra->prev_page + 1;
 }
+EXPORT_SYMBOL(page_cache_readahead);
 
 /*
  * handle_ra_miss() is called when it is known that a page which should have
@@ -542,6 +543,7 @@ void handle_ra_miss(struct address_space
 	ra->flags |= RA_FLAG_MISS;
 	ra->flags &= ~RA_FLAG_INCACHE;
 }
+EXPORT_SYMBOL(handle_ra_miss);
 
 /*
  * Given a desired number of PAGE_CACHE_SIZE readahead pages, return a

_

.