From: John Hubbard <jhubbard@nvidia.com>
To: LKML <linux-kernel@vger.kernel.org>
Cc: John Hubbard <jhubbard@nvidia.com>,
Mike Marshall <hubcap@omnibond.com>,
Martin Brandenburg <martin@omnibond.com>,
<devel@lists.orangefs.org>, <linux-fsdevel@vger.kernel.org>
Subject: [PATCH v2] orangefs: convert get_user_pages() --> pin_user_pages()
Date: Fri, 22 May 2020 20:59:09 -0700 [thread overview]
Message-ID: <20200523035909.418683-1-jhubbard@nvidia.com> (raw)
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
next reply other threads:[~2020-05-23 3:59 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-23 3:59 John Hubbard [this message]
2020-05-30 7:39 ` [PATCH v2] orangefs: convert get_user_pages() --> pin_user_pages() John Hubbard
2020-06-01 11:13 ` Mike Marshall
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