Commit 0df55645 authored May 22, 2020 by John Hubbard Committed by Mike Marshall May 29, 2020

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>

parent 22ce8561

fs/orangefs/orangefs-bufmap.c

+3 −6

Original line number	Diff line number	Diff line
		@@ -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;
		}

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