orangefs: convert get_user_pages() --> pin_user_pages()

This code was using get_user_pages*(), in a "Case 1" scenario
(Direct IO), using the categorization from [1]. That means that it's
time to convert the get_user_pages*() + put_page() calls to
pin_user_pages*() + unpin_user_pages() calls.

There is some helpful background in [2]: basically, this is a small
part of fixing a long-standing disconnect between pinning pages, and
file systems' use of those pages.

[1] Documentation/core-api/pin_user_pages.rst

[2] "Explicit pinning of user-space pages":
    https://lwn.net/Articles/807108/

Cc: Mike Marshall <hubcap@omnibond.com>
Cc: Martin Brandenburg <martin@omnibond.com>
Cc: devel@lists.orangefs.org
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Mike Marshall <hubcap@omnibond.com>

diff --git a/fs/orangefs/orangefs-bufmap.c b/fs/orangefs/orangefs-bufmap.c
index 2bb916d68576fa01e4431017fa812907e117049b..538e839590ef5c1d489aea7f6d94a7e9d1be821b 100644 (file)
--- a/fs/orangefs/orangefs-bufmap.c
+++ b/fs/orangefs/orangefs-bufmap.c
@@ -168,10 +168,7 @@ static DEFINE_SPINLOCK(orangefs_bufmap_lock);
 static void
 orangefs_bufmap_unmap(struct orangefs_bufmap *bufmap)
 {
-       int i;
-
-       for (i = 0; i < bufmap->page_count; i++)
-               put_page(bufmap->page_array[i]);
+       unpin_user_pages(bufmap->page_array, bufmap->page_count);
 }
 
 static void
@@ -268,7 +265,7 @@ orangefs_bufmap_map(struct orangefs_bufmap *bufmap,
        int offset = 0, ret, i;
 
        /* map the pages */
-       ret = get_user_pages_fast((unsigned long)user_desc->ptr,
+       ret = pin_user_pages_fast((unsigned long)user_desc->ptr,
                             bufmap->page_count, FOLL_WRITE, bufmap->page_array);
 
        if (ret < 0)
@@ -280,7 +277,7 @@ orangefs_bufmap_map(struct orangefs_bufmap *bufmap,
 
                for (i = 0; i < ret; i++) {
                        SetPageError(bufmap->page_array[i]);
-                       put_page(bufmap->page_array[i]);
+                       unpin_user_page(bufmap->page_array[i]);
                }
                return -ENOMEM;
        }