NFS: Create a generic_pgio function
These functions are almost identical on both the read and write side.
FLUSH_COND_STABLE will never be set for the read path, so leaving it in
the generic code won't hurt anything.
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index b0a98da..d8d25a4 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -27,6 +27,7 @@
#define NFSDBG_FACILITY NFSDBG_PAGECACHE
static struct kmem_cache *nfs_page_cachep;
+static const struct rpc_call_ops nfs_pgio_common_ops;
static bool nfs_pgarray_set(struct nfs_page_array *p, unsigned int pagecount)
{
@@ -338,8 +339,8 @@
* @hdr: The header making a request
* @pagecount: Number of pages to create
*/
-struct nfs_pgio_data *nfs_pgio_data_alloc(struct nfs_pgio_header *hdr,
- unsigned int pagecount)
+static struct nfs_pgio_data *nfs_pgio_data_alloc(struct nfs_pgio_header *hdr,
+ unsigned int pagecount)
{
struct nfs_pgio_data *data, *prealloc;
@@ -396,7 +397,7 @@
* @how: How to commit data (writes only)
* @cinfo: Commit information for the call (writes only)
*/
-void nfs_pgio_rpcsetup(struct nfs_pgio_data *data,
+static void nfs_pgio_rpcsetup(struct nfs_pgio_data *data,
unsigned int count, unsigned int offset,
int how, struct nfs_commit_info *cinfo)
{
@@ -451,7 +452,7 @@
* @desc: IO descriptor
* @hdr: pageio header
*/
-int nfs_pgio_error(struct nfs_pageio_descriptor *desc,
+static int nfs_pgio_error(struct nfs_pageio_descriptor *desc,
struct nfs_pgio_header *hdr)
{
struct nfs_pgio_data *data;
@@ -534,6 +535,101 @@
data->header->rw_ops->rw_result(task, data);
}
+/*
+ * Generate multiple small requests to read or write a single
+ * contiguous dirty on one page.
+ */
+static int nfs_pgio_multi(struct nfs_pageio_descriptor *desc,
+ struct nfs_pgio_header *hdr)
+{
+ struct nfs_page *req = hdr->req;
+ struct page *page = req->wb_page;
+ struct nfs_pgio_data *data;
+ size_t wsize = desc->pg_bsize, nbytes;
+ unsigned int offset;
+ int requests = 0;
+ struct nfs_commit_info cinfo;
+
+ nfs_init_cinfo(&cinfo, desc->pg_inode, desc->pg_dreq);
+
+ if ((desc->pg_ioflags & FLUSH_COND_STABLE) &&
+ (desc->pg_moreio || nfs_reqs_to_commit(&cinfo) ||
+ desc->pg_count > wsize))
+ desc->pg_ioflags &= ~FLUSH_COND_STABLE;
+
+ offset = 0;
+ nbytes = desc->pg_count;
+ do {
+ size_t len = min(nbytes, wsize);
+
+ data = nfs_pgio_data_alloc(hdr, 1);
+ if (!data)
+ return nfs_pgio_error(desc, hdr);
+ data->pages.pagevec[0] = page;
+ nfs_pgio_rpcsetup(data, len, offset, desc->pg_ioflags, &cinfo);
+ list_add(&data->list, &hdr->rpc_list);
+ requests++;
+ nbytes -= len;
+ offset += len;
+ } while (nbytes != 0);
+
+ nfs_list_remove_request(req);
+ nfs_list_add_request(req, &hdr->pages);
+ desc->pg_rpc_callops = &nfs_pgio_common_ops;
+ return 0;
+}
+
+/*
+ * Create an RPC task for the given read or write request and kick it.
+ * The page must have been locked by the caller.
+ *
+ * It may happen that the page we're passed is not marked dirty.
+ * This is the case if nfs_updatepage detects a conflicting request
+ * that has been written but not committed.
+ */
+static int nfs_pgio_one(struct nfs_pageio_descriptor *desc,
+ struct nfs_pgio_header *hdr)
+{
+ struct nfs_page *req;
+ struct page **pages;
+ struct nfs_pgio_data *data;
+ struct list_head *head = &desc->pg_list;
+ struct nfs_commit_info cinfo;
+
+ data = nfs_pgio_data_alloc(hdr, nfs_page_array_len(desc->pg_base,
+ desc->pg_count));
+ if (!data)
+ return nfs_pgio_error(desc, hdr);
+
+ nfs_init_cinfo(&cinfo, desc->pg_inode, desc->pg_dreq);
+ pages = data->pages.pagevec;
+ while (!list_empty(head)) {
+ req = nfs_list_entry(head->next);
+ nfs_list_remove_request(req);
+ nfs_list_add_request(req, &hdr->pages);
+ *pages++ = req->wb_page;
+ }
+
+ if ((desc->pg_ioflags & FLUSH_COND_STABLE) &&
+ (desc->pg_moreio || nfs_reqs_to_commit(&cinfo)))
+ desc->pg_ioflags &= ~FLUSH_COND_STABLE;
+
+ /* Set up the argument struct */
+ nfs_pgio_rpcsetup(data, desc->pg_count, 0, desc->pg_ioflags, &cinfo);
+ list_add(&data->list, &hdr->rpc_list);
+ desc->pg_rpc_callops = &nfs_pgio_common_ops;
+ return 0;
+}
+
+int nfs_generic_pgio(struct nfs_pageio_descriptor *desc,
+ struct nfs_pgio_header *hdr)
+{
+ if (desc->pg_bsize < PAGE_CACHE_SIZE)
+ return nfs_pgio_multi(desc, hdr);
+ return nfs_pgio_one(desc, hdr);
+}
+EXPORT_SYMBOL_GPL(nfs_generic_pgio);
+
static bool nfs_match_open_context(const struct nfs_open_context *ctx1,
const struct nfs_open_context *ctx2)
{
@@ -741,7 +837,7 @@
kmem_cache_destroy(nfs_page_cachep);
}
-const struct rpc_call_ops nfs_pgio_common_ops = {
+static const struct rpc_call_ops nfs_pgio_common_ops = {
.rpc_call_prepare = nfs_pgio_prepare,
.rpc_call_done = nfs_pgio_result,
.rpc_release = nfs_pgio_release,