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

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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>
This commit is contained in:
John Hubbard 2020-05-22 20:59:09 -07:00 committed by Mike Marshall
parent 22ce85611f
commit 0df5564577
1 changed files with 3 additions and 6 deletions
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9
fs/orangefs/orangefs-bufmap.c
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@ -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;
}