nfs: modify pg_test interface to return size_t
This is a step toward allowing pg_test to inform the the
coalescing code to reduce the size of requests so they may fit in
whatever scheme the pg_test callback wants to define.
For now, just return the size of the request if there is space, or 0
if there is not. This shouldn't change any behavior as it acts
the same as when the pg_test functions returned bool.
Signed-off-by: Weston Andros Adamson <dros@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
diff --git a/fs/nfs/nfs4filelayout.c b/fs/nfs/nfs4filelayout.c
index 9fd7ceb..ba9a9aa 100644
--- a/fs/nfs/nfs4filelayout.c
+++ b/fs/nfs/nfs4filelayout.c
@@ -915,10 +915,10 @@
/*
* filelayout_pg_test(). Called by nfs_can_coalesce_requests()
*
- * return true : coalesce page
- * return false : don't coalesce page
+ * Return 0 if @req cannot be coalesced into @pgio, otherwise return the number
+ * of bytes (maximum @req->wb_bytes) that can be coalesced.
*/
-static bool
+static size_t
filelayout_pg_test(struct nfs_pageio_descriptor *pgio, struct nfs_page *prev,
struct nfs_page *req)
{
@@ -927,7 +927,7 @@
if (!pnfs_generic_pg_test(pgio, prev, req) ||
!nfs_generic_pg_test(pgio, prev, req))
- return false;
+ return 0;
p_stripe = (u64)req_offset(prev);
r_stripe = (u64)req_offset(req);
@@ -936,7 +936,9 @@
do_div(p_stripe, stripe_unit);
do_div(r_stripe, stripe_unit);
- return (p_stripe == r_stripe);
+ if (p_stripe == r_stripe)
+ return req->wb_bytes;
+ return 0;
}
static void