linux-kernel - [PATCH 3/3] mm/ksm: convert put_page() to put_user

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Message-Id: <20190805222019.28592-4-jhubbard@nvidia.com>
Date:   Mon,  5 Aug 2019 15:20:19 -0700
From:   john.hubbard@...il.com
To:     Andrew Morton <akpm@...ux-foundation.org>
Cc:     Christoph Hellwig <hch@...radead.org>,
        Ira Weiny <ira.weiny@...el.com>, Jan Kara <jack@...e.cz>,
        Jason Gunthorpe <jgg@...pe.ca>,
        Jerome Glisse <jglisse@...hat.com>,
        LKML <linux-kernel@...r.kernel.org>, linux-mm@...ck.org,
        linux-fsdevel@...r.kernel.org, John Hubbard <jhubbard@...dia.com>,
        Dan Williams <dan.j.williams@...el.com>,
        Daniel Black <daniel@...ux.ibm.com>,
        Matthew Wilcox <willy@...radead.org>,
        Mike Kravetz <mike.kravetz@...cle.com>
Subject: [PATCH 3/3] mm/ksm: 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: Dan Williams <dan.j.williams@...el.com>
Cc: Daniel Black <daniel@...ux.ibm.com>
Cc: Jan Kara <jack@...e.cz>
Cc: Jérôme Glisse <jglisse@...hat.com>
Cc: Matthew Wilcox <willy@...radead.org>
Cc: Mike Kravetz <mike.kravetz@...cle.com>
Signed-off-by: John Hubbard <jhubbard@...dia.com>
---
 mm/ksm.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/mm/ksm.c b/mm/ksm.c
index 3dc4346411e4..e10ee4d5fdd8 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -456,7 +456,7 @@ static inline bool ksm_test_exit(struct mm_struct *mm)
  * We use break_ksm to break COW on a ksm page: it's a stripped down
  *
  *	if (get_user_pages(addr, 1, 1, 1, &page, NULL) == 1)
- *		put_page(page);
+ *		put_user_page(page);
  *
  * but taking great care only to touch a ksm page, in a VM_MERGEABLE vma,
  * in case the application has unmapped and remapped mm,addr meanwhile.
@@ -483,7 +483,7 @@ static int break_ksm(struct vm_area_struct *vma, unsigned long addr)
 					FAULT_FLAG_WRITE | FAULT_FLAG_REMOTE);
 		else
 			ret = VM_FAULT_WRITE;
-		put_page(page);
+		put_user_page(page);
 	} while (!(ret & (VM_FAULT_WRITE | VM_FAULT_SIGBUS | VM_FAULT_SIGSEGV | VM_FAULT_OOM)));
 	/*
 	 * We must loop because handle_mm_fault() may back out if there's
@@ -568,7 +568,7 @@ static struct page *get_mergeable_page(struct rmap_item *rmap_item)
 		flush_anon_page(vma, page, addr);
 		flush_dcache_page(page);
 	} else {
-		put_page(page);
+		put_user_page(page);
 out:
 		page = NULL;
 	}
@@ -1974,10 +1974,10 @@ struct rmap_item *unstable_tree_search_insert(struct rmap_item *rmap_item,
 
 		parent = *new;
 		if (ret < 0) {
-			put_page(tree_page);
+			put_user_page(tree_page);
 			new = &parent->rb_left;
 		} else if (ret > 0) {
-			put_page(tree_page);
+			put_user_page(tree_page);
 			new = &parent->rb_right;
 		} else if (!ksm_merge_across_nodes &&
 			   page_to_nid(tree_page) != nid) {
@@ -1986,7 +1986,7 @@ struct rmap_item *unstable_tree_search_insert(struct rmap_item *rmap_item,
 			 * it will be flushed out and put in the right unstable
 			 * tree next time: only merge with it when across_nodes.
 			 */
-			put_page(tree_page);
+			put_user_page(tree_page);
 			return NULL;
 		} else {
 			*tree_pagep = tree_page;
@@ -2328,7 +2328,7 @@ static struct rmap_item *scan_get_next_rmap_item(struct page **page)
 							&rmap_item->rmap_list;
 					ksm_scan.address += PAGE_SIZE;
 				} else
-					put_page(*page);
+					put_user_page(*page);
 				up_read(&mm->mmap_sem);
 				return rmap_item;
 			}
-- 
2.22.0