linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
* [PATCH v2] orangefs: convert get_user_pages() --> pin_user_pages()
@ 2020-05-23  3:59 John Hubbard
  2020-05-30  7:39 ` John Hubbard
  0 siblings, 1 reply; 3+ messages in thread
From: John Hubbard @ 2020-05-23  3:59 UTC (permalink / raw)
  To: LKML
  Cc: John Hubbard, Mike Marshall, Martin Brandenburg, devel, linux-fsdevel

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>
---

Hi,

Note that I have only compile-tested this patch, although that does
also include cross-compiling for a few other arches.

Changes since v1 [3]: correct the commit description, so that
it refers to "Case 1" instead of "Case 2".


[3] https://lore.kernel.org/r/20200518060139.2828423-1-jhubbard@nvidia.com

thanks,
John Hubbard
NVIDIA

 fs/orangefs/orangefs-bufmap.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/fs/orangefs/orangefs-bufmap.c b/fs/orangefs/orangefs-bufmap.c
index 2bb916d68576..538e839590ef 100644
--- 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;
 	}
-- 
2.26.2


^ permalink raw reply related	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2020-06-01 11:14 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-05-23  3:59 [PATCH v2] orangefs: convert get_user_pages() --> pin_user_pages() John Hubbard
2020-05-30  7:39 ` John Hubbard
2020-06-01 11:13   ` Mike Marshall

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).