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From: John Hubbard <jhubbard@nvidia.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: "Al Viro" <viro@zeniv.linux.org.uk>,
	"Alex Williamson" <alex.williamson@redhat.com>,
	"Benjamin Herrenschmidt" <benh@kernel.crashing.org>,
	"Björn Töpel" <bjorn.topel@intel.com>,
	"Christoph Hellwig" <hch@infradead.org>,
	"Dan Williams" <dan.j.williams@intel.com>,
	"Daniel Vetter" <daniel@ffwll.ch>,
	"Dave Chinner" <david@fromorbit.com>,
	"David Airlie" <airlied@linux.ie>,
	"David S . Miller" <davem@davemloft.net>,
	"Ira Weiny" <ira.weiny@intel.com>, "Jan Kara" <jack@suse.cz>,
	"Jason Gunthorpe" <jgg@ziepe.ca>, "Jens Axboe" <axboe@kernel.dk>,
	"Jonathan Corbet" <corbet@lwn.net>,
	"Jérôme Glisse" <jglisse@redhat.com>,
	"Kirill A . Shutemov" <kirill@shutemov.name>,
	"Magnus Karlsson" <magnus.karlsson@intel.com>,
	"Mauro Carvalho Chehab" <mchehab@kernel.org>,
	"Michael Ellerman" <mpe@ellerman.id.au>,
	"Michal Hocko" <mhocko@suse.com>,
	"Mike Kravetz" <mike.kravetz@oracle.com>,
	"Paul Mackerras" <paulus@samba.org>,
	"Shuah Khan" <shuah@kernel.org>,
	"Vlastimil Babka" <vbabka@suse.cz>,
	bpf@vger.kernel.org, dri-devel@lists.freedesktop.org,
	kvm@vger.kernel.org, linux-block@vger.kernel.org,
	linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-kselftest@vger.kernel.org, linux-media@vger.kernel.org,
	linux-rdma@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
	netdev@vger.kernel.org, linux-mm@kvack.org,
	LKML <linux-kernel@vger.kernel.org>,
	"John Hubbard" <jhubbard@nvidia.com>
Subject: [PATCH v12 14/22] mm/process_vm_access: set FOLL_PIN via pin_user_pages_remote()
Date: Tue, 7 Jan 2020 14:45:50 -0800
Message-ID: <20200107224558.2362728-15-jhubbard@nvidia.com> (raw)
In-Reply-To: <20200107224558.2362728-1-jhubbard@nvidia.com>

Convert process_vm_access to use the new pin_user_pages_remote()
call, which sets FOLL_PIN. Setting FOLL_PIN is now required for
code that requires tracking of pinned pages.

Also, release the pages via put_user_page*().

Also, rename "pages" to "pinned_pages", as this makes for
easier reading of process_vm_rw_single_vec().

Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jérôme Glisse <jglisse@redhat.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
---
 mm/process_vm_access.c | 28 +++++++++++++++-------------
 1 file changed, 15 insertions(+), 13 deletions(-)

diff --git a/mm/process_vm_access.c b/mm/process_vm_access.c
index 357aa7bef6c0..fd20ab675b85 100644
--- a/mm/process_vm_access.c
+++ b/mm/process_vm_access.c
@@ -42,12 +42,11 @@ static int process_vm_rw_pages(struct page **pages,
 		if (copy > len)
 			copy = len;
 
-		if (vm_write) {
+		if (vm_write)
 			copied = copy_page_from_iter(page, offset, copy, iter);
-			set_page_dirty_lock(page);
-		} else {
+		else
 			copied = copy_page_to_iter(page, offset, copy, iter);
-		}
+
 		len -= copied;
 		if (copied < copy && iov_iter_count(iter))
 			return -EFAULT;
@@ -96,7 +95,7 @@ static int process_vm_rw_single_vec(unsigned long addr,
 		flags |= FOLL_WRITE;
 
 	while (!rc && nr_pages && iov_iter_count(iter)) {
-		int pages = min(nr_pages, max_pages_per_loop);
+		int pinned_pages = min(nr_pages, max_pages_per_loop);
 		int locked = 1;
 		size_t bytes;
 
@@ -106,14 +105,15 @@ static int process_vm_rw_single_vec(unsigned long addr,
 		 * current/current->mm
 		 */
 		down_read(&mm->mmap_sem);
-		pages = get_user_pages_remote(task, mm, pa, pages, flags,
-					      process_pages, NULL, &locked);
+		pinned_pages = pin_user_pages_remote(task, mm, pa, pinned_pages,
+						     flags, process_pages,
+						     NULL, &locked);
 		if (locked)
 			up_read(&mm->mmap_sem);
-		if (pages <= 0)
+		if (pinned_pages <= 0)
 			return -EFAULT;
 
-		bytes = pages * PAGE_SIZE - start_offset;
+		bytes = pinned_pages * PAGE_SIZE - start_offset;
 		if (bytes > len)
 			bytes = len;
 
@@ -122,10 +122,12 @@ static int process_vm_rw_single_vec(unsigned long addr,
 					 vm_write);
 		len -= bytes;
 		start_offset = 0;
-		nr_pages -= pages;
-		pa += pages * PAGE_SIZE;
-		while (pages)
-			put_page(process_pages[--pages]);
+		nr_pages -= pinned_pages;
+		pa += pinned_pages * PAGE_SIZE;
+
+		/* If vm_write is set, the pages need to be made dirty: */
+		put_user_pages_dirty_lock(process_pages, pinned_pages,
+					  vm_write);
 	}
 
 	return rc;
-- 
2.24.1


  parent reply index

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-07 22:45 [PATCH v12 00/22] mm/gup: prereqs to track dma-pinned pages: FOLL_PIN John Hubbard
2020-01-07 22:45 ` [PATCH v12 01/22] mm/gup: factor out duplicate code from four routines John Hubbard
2020-01-07 22:45 ` [PATCH v12 02/22] mm/gup: move try_get_compound_head() to top, fix minor issues John Hubbard
2020-01-07 22:45 ` [PATCH v12 03/22] mm: Cleanup __put_devmap_managed_page() vs ->page_free() John Hubbard
2020-01-07 22:45 ` [PATCH v12 04/22] mm: devmap: refactor 1-based refcounting for ZONE_DEVICE pages John Hubbard
2020-01-15 15:23   ` Christoph Hellwig
2020-01-15 21:19     ` John Hubbard
2020-01-16  9:37       ` Christoph Hellwig
2020-01-16 20:30         ` John Hubbard
2020-01-07 22:45 ` [PATCH v12 05/22] goldish_pipe: rename local pin_user_pages() routine John Hubbard
2020-01-15 15:23   ` Christoph Hellwig
2020-01-07 22:45 ` [PATCH v12 06/22] mm: fix get_user_pages_remote()'s handling of FOLL_LONGTERM John Hubbard
2020-01-15 15:24   ` Christoph Hellwig
2020-01-07 22:45 ` [PATCH v12 07/22] vfio: fix FOLL_LONGTERM use, simplify get_user_pages_remote() call John Hubbard
2020-01-07 22:45 ` [PATCH v12 08/22] mm/gup: allow FOLL_FORCE for get_user_pages_fast() John Hubbard
2020-01-15 15:25   ` Christoph Hellwig
2020-01-07 22:45 ` [PATCH v12 09/22] IB/umem: use get_user_pages_fast() to pin DMA pages John Hubbard
2020-01-07 22:45 ` [PATCH v12 10/22] media/v4l2-core: set pages dirty upon releasing DMA buffers John Hubbard
2020-01-07 22:45 ` [PATCH v12 11/22] mm/gup: introduce pin_user_pages*() and FOLL_PIN John Hubbard
2020-01-15 15:30   ` Christoph Hellwig
2020-01-15 21:34     ` John Hubbard
2020-01-07 22:45 ` [PATCH v12 12/22] goldish_pipe: convert to pin_user_pages() and put_user_page() John Hubbard
2020-01-07 22:45 ` [PATCH v12 13/22] IB/{core,hw,umem}: set FOLL_PIN via pin_user_pages*(), fix up ODP John Hubbard
2020-01-07 22:45 ` John Hubbard [this message]
2020-01-07 22:45 ` [PATCH v12 15/22] drm/via: set FOLL_PIN via pin_user_pages_fast() John Hubbard
2020-01-07 22:45 ` [PATCH v12 16/22] fs/io_uring: set FOLL_PIN via pin_user_pages() John Hubbard
2020-01-07 22:45 ` [PATCH v12 17/22] net/xdp: " John Hubbard
2020-01-07 22:45 ` [PATCH v12 18/22] media/v4l2-core: pin_user_pages (FOLL_PIN) and put_user_page() conversion John Hubbard
2020-01-07 22:45 ` [PATCH v12 19/22] vfio, mm: " John Hubbard
2020-01-07 22:45 ` [PATCH v12 20/22] powerpc: book3s64: convert to pin_user_pages() and put_user_page() John Hubbard
2020-01-07 22:45 ` [PATCH v12 21/22] mm/gup_benchmark: use proper FOLL_WRITE flags instead of hard-coding "1" John Hubbard
2020-01-07 22:45 ` [PATCH v12 22/22] mm, tree-wide: rename put_user_page*() to unpin_user_page*() John Hubbard
2020-01-15 15:26   ` Christoph Hellwig
2020-01-09 22:07 ` [PATCH v12 00/22] mm/gup: prereqs to track dma-pinned pages: FOLL_PIN John Hubbard
2020-01-14 20:15   ` John Hubbard
2020-01-14 23:29     ` Andrew Morton

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