[RFC PATCH 02/09] Change wdata alloc to support direct pages

[Long Li <longli@linuxonhyperv.com>]

From: Long Li <longli@microsoft.com>

When using direct pages from user space, there is no need to allocate pages.

Just ping those user pages for RDMA.

Signed-off-by: Long Li <longli@microsoft.com>
---
 fs/cifs/cifsproto.h |  2 +-
 fs/cifs/cifssmb.c   | 10 +++++++---
 fs/cifs/file.c      |  4 ++--
 3 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index 365a414..94106b9 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -523,7 +523,7 @@ int cifs_readv_receive(struct TCP_Server_Info *server, struct mid_q_entry *mid);
 int cifs_async_writev(struct cifs_writedata *wdata,
 		      void (*release)(struct kref *kref));
 void cifs_writev_complete(struct work_struct *work);
-struct cifs_writedata *cifs_writedata_alloc(unsigned int nr_pages,
+struct cifs_writedata *cifs_writedata_alloc(unsigned int nr_pages, struct page **direct_pages,
 						work_func_t complete);
 void cifs_writedata_release(struct kref *refcount);
 int cifs_query_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index 1529a08..3b1731d 100644
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -1983,7 +1983,7 @@ cifs_writev_requeue(struct cifs_writedata *wdata)
 			tailsz = rest_len - (nr_pages - 1) * PAGE_SIZE;
 		}
 
-		wdata2 = cifs_writedata_alloc(nr_pages, cifs_writev_complete);
+		wdata2 = cifs_writedata_alloc(nr_pages, NULL, cifs_writev_complete);
 		if (!wdata2) {
 			rc = -ENOMEM;
 			break;
@@ -2067,12 +2067,16 @@ cifs_writev_complete(struct work_struct *work)
 }
 
 struct cifs_writedata *
-cifs_writedata_alloc(unsigned int nr_pages, work_func_t complete)
+cifs_writedata_alloc(unsigned int nr_pages, struct page **direct_pages, work_func_t complete)
 {
 	struct cifs_writedata *wdata;
 
 	/* writedata + number of page pointers */
-	wdata = kzalloc(sizeof(*wdata) +
+	if (direct_pages) {
+		wdata = kzalloc(sizeof(*wdata), GFP_NOFS);
+		wdata->direct_pages = direct_pages;
+	} else
+		wdata = kzalloc(sizeof(*wdata) +
 			sizeof(struct page *) * nr_pages, GFP_NOFS);
 	if (wdata != NULL) {
 		kref_init(&wdata->refcount);
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 23fd430..a6ec896 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -1965,7 +1965,7 @@ wdata_alloc_and_fillpages(pgoff_t tofind, struct address_space *mapping,
 {
 	struct cifs_writedata *wdata;
 
-	wdata = cifs_writedata_alloc((unsigned int)tofind,
+	wdata = cifs_writedata_alloc((unsigned int)tofind, NULL,
 				     cifs_writev_complete);
 	if (!wdata)
 		return NULL;
@@ -2554,7 +2554,7 @@ cifs_write_from_iter(loff_t offset, size_t len, struct iov_iter *from,
 			break;
 
 		nr_pages = get_numpages(wsize, len, &cur_len);
-		wdata = cifs_writedata_alloc(nr_pages,
+		wdata = cifs_writedata_alloc(nr_pages, NULL,
 					     cifs_uncached_writev_complete);
 		if (!wdata) {
 			rc = -ENOMEM;
-- 
2.7.4