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authorMike Kravetz <mike.kravetz@oracle.com>2018-06-07 17:05:53 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-06-07 17:34:34 -0700
commit5b9c98f3082b4e8a24ef5e6bb21ed0558b54349a (patch)
tree31596c393338aa139003aabf2776df2d1b708b1f
parentc0265342bff4fcaa2cdf13f4596244c18d4a7ae5 (diff)
mm/shmem: add __rcu annotations and properly deref radix entry
Patch series "restructure memfd code", v4. This patch (of 3): In preparation for memfd code restucture, clean up sparse warnings. Most changes required adding __rcu annotations. The routine find_swap_entry was modified to properly deference radix tree entries. Link: http://lkml.kernel.org/r/20180415182119.4517-2-mike.kravetz@oracle.com Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Matthew Wilcox <willy@infradead.org> Cc: Hugh Dickins <hughd@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Marc-Andr Lureau <marcandre.lureau@gmail.com> Cc: David Herrmann <dh.herrmann@gmail.com> Cc: Khalid Aziz <khalid.aziz@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/shmem.c20
1 files changed, 13 insertions, 7 deletions
diff --git a/mm/shmem.c b/mm/shmem.c
index 8c43e207cd3b..54bec60380df 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -327,7 +327,7 @@ static int shmem_radix_tree_replace(struct address_space *mapping,
pgoff_t index, void *expected, void *replacement)
{
struct radix_tree_node *node;
- void **pslot;
+ void __rcu **pslot;
void *item;
VM_BUG_ON(!expected);
@@ -395,7 +395,7 @@ static bool shmem_confirm_swap(struct address_space *mapping,
#ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE
/* ifdef here to avoid bloating shmem.o when not necessary */
-int shmem_huge __read_mostly;
+static int shmem_huge __read_mostly;
#if defined(CONFIG_SYSFS) || defined(CONFIG_TMPFS)
static int shmem_parse_huge(const char *str)
@@ -682,7 +682,7 @@ unsigned long shmem_partial_swap_usage(struct address_space *mapping,
pgoff_t start, pgoff_t end)
{
struct radix_tree_iter iter;
- void **slot;
+ void __rcu **slot;
struct page *page;
unsigned long swapped = 0;
@@ -1098,13 +1098,19 @@ static void shmem_evict_inode(struct inode *inode)
static unsigned long find_swap_entry(struct radix_tree_root *root, void *item)
{
struct radix_tree_iter iter;
- void **slot;
+ void __rcu **slot;
unsigned long found = -1;
unsigned int checked = 0;
rcu_read_lock();
radix_tree_for_each_slot(slot, root, &iter, 0) {
- if (*slot == item) {
+ void *entry = radix_tree_deref_slot(slot);
+
+ if (radix_tree_deref_retry(entry)) {
+ slot = radix_tree_iter_retry(&iter);
+ continue;
+ }
+ if (entry == item) {
found = iter.index;
break;
}
@@ -2622,7 +2628,7 @@ static loff_t shmem_file_llseek(struct file *file, loff_t offset, int whence)
static void shmem_tag_pins(struct address_space *mapping)
{
struct radix_tree_iter iter;
- void **slot;
+ void __rcu **slot;
pgoff_t start;
struct page *page;
@@ -2664,7 +2670,7 @@ static void shmem_tag_pins(struct address_space *mapping)
static int shmem_wait_for_pins(struct address_space *mapping)
{
struct radix_tree_iter iter;
- void **slot;
+ void __rcu **slot;
pgoff_t start;
struct page *page;
int error, scan;