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/pagelist.c b/fs/nfs/pagelist.c
index 4b4b212..8223343 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -280,7 +280,17 @@
TASK_UNINTERRUPTIBLE);
}
-bool nfs_generic_pg_test(struct nfs_pageio_descriptor *desc, struct nfs_page *prev, struct nfs_page *req)
+/*
+ * nfs_generic_pg_test - determine if requests can be coalesced
+ * @desc: pointer to descriptor
+ * @prev: previous request in desc, or NULL
+ * @req: this request
+ *
+ * Returns zero if @req can be coalesced into @desc, otherwise it returns
+ * the size of the request.
+ */
+size_t nfs_generic_pg_test(struct nfs_pageio_descriptor *desc,
+ struct nfs_page *prev, struct nfs_page *req)
{
/*
* FIXME: ideally we should be able to coalesce all requests
@@ -292,7 +302,9 @@
if (desc->pg_bsize < PAGE_SIZE)
return 0;
- return desc->pg_count + req->wb_bytes <= desc->pg_bsize;
+ if (desc->pg_count + req->wb_bytes <= desc->pg_bsize)
+ return req->wb_bytes;
+ return 0;
}
EXPORT_SYMBOL_GPL(nfs_generic_pg_test);
@@ -747,6 +759,8 @@
struct nfs_page *req,
struct nfs_pageio_descriptor *pgio)
{
+ size_t size;
+
if (!nfs_match_open_context(req->wb_context, prev->wb_context))
return false;
if (req->wb_context->dentry->d_inode->i_flock != NULL &&
@@ -758,7 +772,9 @@
return false;
if (req_offset(req) != req_offset(prev) + prev->wb_bytes)
return false;
- return pgio->pg_ops->pg_test(pgio, prev, req);
+ size = pgio->pg_ops->pg_test(pgio, prev, req);
+ WARN_ON_ONCE(size && size != req->wb_bytes);
+ return size > 0;
}
/**