From: john.hubbard@gmail.com
To: Matthew Wilcox <willy@infradead.org>,
Michal Hocko <mhocko@kernel.org>,
Christopher Lameter <cl@linux.com>,
Jason Gunthorpe <jgg@ziepe.ca>,
Dan Williams <dan.j.williams@intel.com>, Jan Kara <jack@suse.cz>,
Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>,
linux-rdma <linux-rdma@vger.kernel.org>,
linux-fsdevel@vger.kernel.org, John Hubbard <jhubbard@nvidia.com>
Subject: [PATCH 2/4] mm: introduce put_user_page(), placeholder version
Date: Thu, 27 Sep 2018 22:39:48 -0700 [thread overview]
Message-ID: <20180928053949.5381-4-jhubbard@nvidia.com> (raw)
In-Reply-To: <20180928053949.5381-1-jhubbard@nvidia.com>
From: John Hubbard <jhubbard@nvidia.com>
Introduces put_user_page(), which simply calls put_page().
This provides a way to update all get_user_pages*() callers,
so that they call put_user_page(), instead of put_page().
Also adds release_user_pages(), a drop-in replacement for
release_pages(). This is intended to be easily grep-able,
for later performance improvements, since release_user_pages
is not batched like release_pages() is, and is significantly
slower.
Also: rename goldfish_pipe.c's release_user_pages(), in order
to avoid a naming conflict with the new external function of
the same name.
This prepares for eventually fixing the problem described
in [1], and is following a plan listed in [2].
[1] https://lwn.net/Articles/753027/ : "The Trouble with get_user_pages()"
[2] https://lkml.kernel.org/r/20180709080554.21931-1-jhubbard@nvidia.com
Proposed steps for fixing get_user_pages() + DMA problems.
CC: Matthew Wilcox <willy@infradead.org>
CC: Michal Hocko <mhocko@kernel.org>
CC: Christopher Lameter <cl@linux.com>
CC: Jason Gunthorpe <jgg@ziepe.ca>
CC: Dan Williams <dan.j.williams@intel.com>
CC: Jan Kara <jack@suse.cz>
CC: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
---
drivers/platform/goldfish/goldfish_pipe.c | 4 ++--
include/linux/mm.h | 14 ++++++++++++++
2 files changed, 16 insertions(+), 2 deletions(-)
diff --git a/drivers/platform/goldfish/goldfish_pipe.c b/drivers/platform/goldfish/goldfish_pipe.c
index 2da567540c2d..fad0345376e0 100644
--- a/drivers/platform/goldfish/goldfish_pipe.c
+++ b/drivers/platform/goldfish/goldfish_pipe.c
@@ -332,7 +332,7 @@ static int pin_user_pages(unsigned long first_page, unsigned long last_page,
}
-static void release_user_pages(struct page **pages, int pages_count,
+static void __release_user_pages(struct page **pages, int pages_count,
int is_write, s32 consumed_size)
{
int i;
@@ -410,7 +410,7 @@ static int transfer_max_buffers(struct goldfish_pipe *pipe,
*consumed_size = pipe->command_buffer->rw_params.consumed_size;
- release_user_pages(pages, pages_count, is_write, *consumed_size);
+ __release_user_pages(pages, pages_count, is_write, *consumed_size);
mutex_unlock(&pipe->lock);
diff --git a/include/linux/mm.h b/include/linux/mm.h
index a61ebe8ad4ca..72caf803115f 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -943,6 +943,20 @@ static inline void put_page(struct page *page)
__put_page(page);
}
+/* Placeholder version, until all get_user_pages*() callers are updated. */
+static inline void put_user_page(struct page *page)
+{
+ put_page(page);
+}
+
+/* A drop-in replacement for release_pages(): */
+static inline void release_user_pages(struct page **pages,
+ unsigned long npages)
+{
+ while (npages)
+ put_user_page(pages[--npages]);
+}
+
#if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
#define SECTION_IN_PAGE_FLAGS
#endif
--
2.19.0
next prev parent reply other threads:[~2018-09-28 5:39 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-28 5:39 [PATCH 0/4] get_user_pages*() and RDMA: first steps john.hubbard
2018-09-28 5:39 ` [PATCH 1/4] mm: get_user_pages: consolidate error handling john.hubbard
2018-09-28 5:39 ` [PATCH 3/4] infiniband/mm: convert to the new put_user_page() call john.hubbard
2018-09-28 15:39 ` Jason Gunthorpe
2018-09-29 3:12 ` John Hubbard
2018-09-29 16:21 ` Matthew Wilcox
2018-09-29 19:19 ` Jason Gunthorpe
2018-10-01 12:50 ` Christoph Hellwig
2018-10-01 15:29 ` Matthew Wilcox
2018-10-01 15:51 ` Christoph Hellwig
2018-10-01 14:35 ` Dennis Dalessandro
2018-10-03 5:40 ` John Hubbard
2018-10-03 16:27 ` Jan Kara
2018-10-03 23:19 ` John Hubbard
2018-09-28 5:39 ` john.hubbard [this message]
2018-10-03 16:22 ` [PATCH 2/4] mm: introduce put_user_page(), placeholder version Jan Kara
2018-10-03 23:23 ` John Hubbard
2018-09-28 5:39 ` [PATCH 4/4] goldfish_pipe/mm: convert to the new release_user_pages() call john.hubbard
2018-09-28 15:29 ` [PATCH 0/4] get_user_pages*() and RDMA: first steps Jerome Glisse
2018-09-28 19:06 ` John Hubbard
2018-09-28 21:49 ` Jerome Glisse
2018-09-29 2:28 ` John Hubbard
2018-09-29 8:46 ` Jerome Glisse
2018-10-01 6:11 ` Dave Chinner
2018-10-01 12:47 ` Christoph Hellwig
2018-10-02 1:14 ` Dave Chinner
2018-10-03 16:21 ` Jan Kara
2018-10-01 15:31 ` Jason Gunthorpe
2018-10-03 16:08 ` Jan Kara
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20180928053949.5381-4-jhubbard@nvidia.com \
--to=john.hubbard@gmail.com \
--cc=cl@linux.com \
--cc=dan.j.williams@intel.com \
--cc=jack@suse.cz \
--cc=jgg@ziepe.ca \
--cc=jhubbard@nvidia.com \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux-rdma@vger.kernel.org \
--cc=mhocko@kernel.org \
--cc=viro@zeniv.linux.org.uk \
--cc=willy@infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
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).