From 22ce85611fd5a793edf84bfc0a101077cbe85e4f Mon Sep 17 00:00:00 2001
From: Colin Ian King <colin.king@canonical.com>
Date: Sun, 24 May 2020 23:48:02 +0100
Subject: [PATCH 1/2] orangefs: remove redundant assignment to variable ret
The variable ret is being initialized with a value that is
never read and it is being updated later with a new value. The
initialization is redundant and can be removed.
Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Mike Marshall <hubcap@omnibond.com>
---
fs/orangefs/orangefs-mod.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/orangefs/orangefs-mod.c b/fs/orangefs/orangefs-mod.c
index c010c1fddafc..289b648ae196 100644
--- a/fs/orangefs/orangefs-mod.c
+++ b/fs/orangefs/orangefs-mod.c
@@ -79,7 +79,7 @@ DECLARE_WAIT_QUEUE_HEAD(orangefs_request_list_waitq);
static int __init orangefs_init(void)
{
- int ret = -1;
+ int ret;
__u32 i = 0;
if (op_timeout_secs < 0)
From 0df556457748d160013e88202c11712c16a83b0c Mon Sep 17 00:00:00 2001
From: John Hubbard <jhubbard@nvidia.com>
Date: Fri, 22 May 2020 20:59:09 -0700
Subject: [PATCH 2/2] 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>
---
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;
}