[RFC 09/11] mm: make rmap_walk void function

Minchan Kim
2017-03-02T06:39:38Z

There is no user of return value from rmap_walk friend so this
patch makes them void function.

Signed-off-by: Minchan Kim <minchan@kernel.org>
---
include/linux/ksm.h | 5 ++---
include/linux/rmap.h | 4 ++--
mm/ksm.c | 16 ++++++----------
mm/rmap.c | 32 +++++++++++++-------------------
4 files changed, 23 insertions(+), 34 deletions(-)

diff --git a/include/linux/ksm.h b/include/linux/ksm.h
index 481c8c4..317ad0b 100644
--- a/include/linux/ksm.h
+++ b/include/linux/ksm.h
@@ -60,7 +60,7 @@ static inline void set_page_stable_node(struct page *page,
struct page *ksm_might_need_to_copy(struct page *page,
struct vm_area_struct *vma, unsigned long address);

-int rmap_walk_ksm(struct page *page, struct rmap_walk_control *rwc);
+void rmap_walk_ksm(struct page *page, struct rmap_walk_control *rwc);
void ksm_migrate_page(struct page *newpage, struct page *oldpage);

#else /* !CONFIG_KSM */
@@ -93,10 +93,9 @@ static inline int page_referenced_ksm(struct page *page,
return 0;
}

-static inline int rmap_walk_ksm(struct page *page,
+static inline void rmap_walk_ksm(struct page *page,
struct rmap_walk_control *rwc)
{
- return 0;
}

static inline void ksm_migrate_page(struct page *newpage, struct page *oldpage)
diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index 6028c38..1d7d457c 100644
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -264,8 +264,8 @@ struct rmap_walk_control {
bool (*invalid_vma)(struct vm_area_struct *vma, void *arg);
};

-int rmap_walk(struct page *page, struct rmap_walk_control *rwc);
-int rmap_walk_locked(struct page *page, struct rmap_walk_control *rwc);
+void rmap_walk(struct page *page, struct rmap_walk_control *rwc);
+void rmap_walk_locked(struct page *page, struct rmap_walk_control *rwc);

#else /* !CONFIG_MMU */

diff --git a/mm/ksm.c b/mm/ksm.c
index 520e4c3..68f8820 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -1931,11 +1931,10 @@ struct page *ksm_might_need_to_copy(struct page *page,
return new_page;
}

-int rmap_walk_ksm(struct page *page, struct rmap_walk_control *rwc)
+void rmap_walk_ksm(struct page *page, struct rmap_walk_control *rwc)
{
struct stable_node *stable_node;
struct rmap_item *rmap_item;
- int ret = SWAP_AGAIN;
int search_new_forks = 0;

VM_BUG_ON_PAGE(!PageKsm(page), page);
@@ -1948,7 +1947,7 @@ int rmap_walk_ksm(struct page *page, struct rmap_walk_control *rwc)

stable_node = page_stable_node(page);
if (!stable_node)
- return ret;
+ return;
again:
hlist_for_each_entry(rmap_item, &stable_node->hlist, hlist) {
struct anon_vma *anon_vma = rmap_item->anon_vma;
@@ -1976,23 +1975,20 @@ int rmap_walk_ksm(struct page *page, struct rmap_walk_control *rwc)
if (rwc->invalid_vma && rwc->invalid_vma(vma, rwc->arg))
continue;

- ret = rwc->rmap_one(page, vma,
- rmap_item->address, rwc->arg);
- if (ret != SWAP_AGAIN) {
+ if (SWAP_AGAIN != rwc->rmap_one(page, vma,
+ rmap_item->address, rwc->arg)) {
anon_vma_unlock_read(anon_vma);
- goto out;
+ return;
}
if (rwc->done && rwc->done(page)) {
anon_vma_unlock_read(anon_vma);
- goto out;
+ return;
}
}
anon_vma_unlock_read(anon_vma);
}
if (!search_new_forks++)
goto again;
-out:
- return ret;
}

#ifdef CONFIG_MIGRATION
diff --git a/mm/rmap.c b/mm/rmap.c
index 01f7832..08e4f81 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1595,13 +1595,12 @@ static struct anon_vma *rmap_walk_anon_lock(struct page *page,
* vm_flags for that VMA. That should be OK, because that vma shouldn't be
* LOCKED.
*/
-static int rmap_walk_anon(struct page *page, struct rmap_walk_control *rwc,
+static void rmap_walk_anon(struct page *page, struct rmap_walk_control *rwc,
bool locked)
{
struct anon_vma *anon_vma;
pgoff_t pgoff_start, pgoff_end;
struct anon_vma_chain *avc;
- int ret = SWAP_AGAIN;

if (locked) {
anon_vma = page_anon_vma(page);
@@ -1611,7 +1610,7 @@ static int rmap_walk_anon(struct page *page, struct rmap_walk_control *rwc,
anon_vma = rmap_walk_anon_lock(page, rwc);
}
if (!anon_vma)
- return ret;
+ return;

pgoff_start = page_to_pgoff(page);
pgoff_end = pgoff_start + hpage_nr_pages(page) - 1;
@@ -1625,8 +1624,7 @@ static int rmap_walk_anon(struct page *page, struct rmap_walk_control *rwc,
if (rwc->invalid_vma && rwc->invalid_vma(vma, rwc->arg))
continue;

- ret = rwc->rmap_one(page, vma, address, rwc->arg);
- if (ret != SWAP_AGAIN)
+ if (SWAP_AGAIN != rwc->rmap_one(page, vma, address, rwc->arg))
break;
if (rwc->done && rwc->done(page))
break;
@@ -1634,7 +1632,6 @@ static int rmap_walk_anon(struct page *page, struct rmap_walk_control *rwc,

if (!locked)
anon_vma_unlock_read(anon_vma);
- return ret;
}

/*
@@ -1650,13 +1647,12 @@ static int rmap_walk_anon(struct page *page, struct rmap_walk_control *rwc,
* vm_flags for that VMA. That should be OK, because that vma shouldn't be
* LOCKED.
*/
-static int rmap_walk_file(struct page *page, struct rmap_walk_control *rwc,
+static void rmap_walk_file(struct page *page, struct rmap_walk_control *rwc,
bool locked)
{
struct address_space *mapping = page_mapping(page);
pgoff_t pgoff_start, pgoff_end;
struct vm_area_struct *vma;
- int ret = SWAP_AGAIN;

/*
* The page lock not only makes sure that page->mapping cannot
@@ -1667,7 +1663,7 @@ static int rmap_walk_file(struct page *page, struct rmap_walk_control *rwc,
VM_BUG_ON_PAGE(!PageLocked(page), page);

if (!mapping)
- return ret;
+ return;

pgoff_start = page_to_pgoff(page);
pgoff_end = pgoff_start + hpage_nr_pages(page) - 1;
@@ -1682,8 +1678,7 @@ static int rmap_walk_file(struct page *page, struct rmap_walk_control *rwc,
if (rwc->invalid_vma && rwc->invalid_vma(vma, rwc->arg))
continue;

- ret = rwc->rmap_one(page, vma, address, rwc->arg);
- if (ret != SWAP_AGAIN)
+ if (SWAP_AGAIN != rwc->rmap_one(page, vma, address, rwc->arg))
goto done;
if (rwc->done && rwc->done(page))
goto done;
@@ -1692,28 +1687,27 @@ static int rmap_walk_file(struct page *page, struct rmap_walk_control *rwc,
done:
if (!locked)
i_mmap_unlock_read(mapping);
- return ret;
}

-int rmap_walk(struct page *page, struct rmap_walk_control *rwc)
+void rmap_walk(struct page *page, struct rmap_walk_control *rwc)
{
if (unlikely(PageKsm(page)))
- return rmap_walk_ksm(page, rwc);
+ rmap_walk_ksm(page, rwc);
else if (PageAnon(page))
- return rmap_walk_anon(page, rwc, false);
+ rmap_walk_anon(page, rwc, false);
else
- return rmap_walk_file(page, rwc, false);
+ rmap_walk_file(page, rwc, false);
}

/* Like rmap_walk, but caller holds relevant rmap lock */
-int rmap_walk_locked(struct page *page, struct rmap_walk_control *rwc)
+void rmap_walk_locked(struct page *page, struct rmap_walk_control *rwc)
{
/* no ksm support for now */
VM_BUG_ON_PAGE(PageKsm(page), page);
if (PageAnon(page))
- return rmap_walk_anon(page, rwc, true);
+ rmap_walk_anon(page, rwc, true);
else
- return rmap_walk_file(page, rwc, true);
+ rmap_walk_file(page, rwc, true);
}

#ifdef CONFIG_HUGETLB_PAGE
--
2.7.4