[Patch v3 03/16] CIFS: Add support for direct pages in wdata

[Long Li]

From: Long Li <lon...@microsoft.com>

Add a function to allocate wdata without allocating pages for data
transfer. This gives the caller an option to pass a number of pages that
point to the data buffer to write to.

wdata is reponsible for free those pages after it's done.

Signed-off-by: Long Li <lon...@microsoft.com>
---
 fs/cifs/cifsglob.h  |  3 +--
 fs/cifs/cifsproto.h |  2 ++
 fs/cifs/cifssmb.c   | 17 ++++++++++++++---
 3 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 166e140..7f62c98 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -1199,14 +1199,13 @@ struct cifs_writedata {
        int                             result;
 #ifdef CONFIG_CIFS_SMB_DIRECT
        struct smbd_mr                  *mr;
-       struct page                     **direct_pages;
 #endif
        unsigned int                    pagesz;
        unsigned int                    page_offset;
        unsigned int                    tailsz;
        unsigned int                    credits;
        unsigned int                    nr_pages;
-       struct page                     *pages[];
+       struct page                     **pages;
 };
 
 /*
diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index 1f27d8e..7933c5f 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -533,6 +533,8 @@ int cifs_async_writev(struct cifs_writedata *wdata,
 void cifs_writev_complete(struct work_struct *work);
 struct cifs_writedata *cifs_writedata_alloc(unsigned int nr_pages,
                                                work_func_t complete);
+struct cifs_writedata *cifs_writedata_direct_alloc(struct page **pages,
+                                               work_func_t complete);
 void cifs_writedata_release(struct kref *refcount);
 int cifs_query_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
                          struct cifs_sb_info *cifs_sb,
diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index a1af258..503e0ed 100644
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -1953,6 +1953,7 @@ cifs_writedata_release(struct kref *refcount)
        if (wdata->cfile)
                cifsFileInfo_put(wdata->cfile);
 
+       kvfree(wdata->pages);
        kfree(wdata);
 }
 
@@ -2076,12 +2077,22 @@ cifs_writev_complete(struct work_struct *work)
 struct cifs_writedata *
 cifs_writedata_alloc(unsigned int nr_pages, work_func_t complete)
 {
+       struct page **pages =
+               kzalloc(sizeof(struct page *) * nr_pages, GFP_NOFS);
+       if (pages)
+               return cifs_writedata_direct_alloc(pages, complete);
+
+       return NULL;
+}
+
+struct cifs_writedata *
+cifs_writedata_direct_alloc(struct page **pages, work_func_t complete)
+{
        struct cifs_writedata *wdata;
 
-       /* writedata + number of page pointers */
-       wdata = kzalloc(sizeof(*wdata) +
-                       sizeof(struct page *) * nr_pages, GFP_NOFS);
+       wdata = kzalloc(sizeof(*wdata), GFP_NOFS);
        if (wdata != NULL) {
+               wdata->pages = pages;
                kref_init(&wdata->refcount);
                INIT_LIST_HEAD(&wdata->list);
                init_completion(&wdata->done);
-- 
2.7.4