linux-kernel - [PATCH v3 31/41] mm/process_vm_access.c: convert put_page() to put_user

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Date:   Tue,  6 Aug 2019 18:33:30 -0700
From:   john.hubbard@...il.com
To:     Andrew Morton <akpm@...ux-foundation.org>
Cc:     Christoph Hellwig <hch@...radead.org>,
        Dan Williams <dan.j.williams@...el.com>,
        Dave Chinner <david@...morbit.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Ira Weiny <ira.weiny@...el.com>, Jan Kara <jack@...e.cz>,
        Jason Gunthorpe <jgg@...pe.ca>,
        Jérôme Glisse <jglisse@...hat.com>,
        LKML <linux-kernel@...r.kernel.org>,
        amd-gfx@...ts.freedesktop.org, ceph-devel@...r.kernel.org,
        devel@...verdev.osuosl.org, devel@...ts.orangefs.org,
        dri-devel@...ts.freedesktop.org, intel-gfx@...ts.freedesktop.org,
        kvm@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-block@...r.kernel.org, linux-crypto@...r.kernel.org,
        linux-fbdev@...r.kernel.org, linux-fsdevel@...r.kernel.org,
        linux-media@...r.kernel.org, linux-mm@...ck.org,
        linux-nfs@...r.kernel.org, linux-rdma@...r.kernel.org,
        linux-rpi-kernel@...ts.infradead.org, linux-xfs@...r.kernel.org,
        netdev@...r.kernel.org, rds-devel@....oracle.com,
        sparclinux@...r.kernel.org, x86@...nel.org,
        xen-devel@...ts.xenproject.org, John Hubbard <jhubbard@...dia.com>,
        Al Viro <viro@...iv.linux.org.uk>,
        Andrea Arcangeli <aarcange@...hat.com>,
        Christopher Yeoh <cyeoh@....ibm.com>,
        Heiko Carstens <heiko.carstens@...ibm.com>,
        Ingo Molnar <mingo@...nel.org>, Jann Horn <jann@...jh.net>,
        Lorenzo Stoakes <lstoakes@...il.com>,
        Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
        Mike Rapoport <rppt@...ux.vnet.ibm.com>,
        Rashika Kheria <rashika.kheria@...il.com>
Subject: [PATCH v3 31/41] mm/process_vm_access.c: convert put_page() to put_user_page*()

From: John Hubbard <jhubbard@...dia.com>

For pages that were retained via get_user_pages*(), release those pages
via the new put_user_page*() routines, instead of via put_page() or
release_pages().

This is part a tree-wide conversion, as described in commit fc1d8e7cca2d
("mm: introduce put_user_page*(), placeholder versions").

Cc: Al Viro <viro@...iv.linux.org.uk>
Cc: Andrea Arcangeli <aarcange@...hat.com>
Cc: Christopher Yeoh <cyeoh@....ibm.com>
Cc: Dave Hansen <dave.hansen@...ux.intel.com>
Cc: Heiko Carstens <heiko.carstens@...ibm.com>
Cc: Ingo Molnar <mingo@...nel.org>
Cc: Jann Horn <jann@...jh.net>
Cc: Lorenzo Stoakes <lstoakes@...il.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@...icios.com>
Cc: Mike Rapoport <rppt@...ux.vnet.ibm.com>
Cc: Rashika Kheria <rashika.kheria@...il.com>
Signed-off-by: John Hubbard <jhubbard@...dia.com>
---
 mm/process_vm_access.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/mm/process_vm_access.c b/mm/process_vm_access.c
index 357aa7bef6c0..4d29d54ec93f 100644
--- a/mm/process_vm_access.c
+++ b/mm/process_vm_access.c
@@ -96,7 +96,7 @@ 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 +106,15 @@ 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 = get_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 +123,9 @@ 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;
+		put_user_pages(process_pages, pinned_pages);
 	}
 
 	return rc;
-- 
2.22.0