Commit 5b9c98f3 authored by Mike Kravetz's avatar Mike Kravetz Committed by Linus Torvalds
Browse files

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: default avatarMike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: default avatarMatthew 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent c0265342

mm/shmem.c

+13 −7
Original line number Original line Diff line number Diff line
@@ -327,7 +327,7 @@ static int shmem_radix_tree_replace(struct address_space *mapping, 
			pgoff_t index, void *expected, void *replacement)

			pgoff_t index, void *expected, void *replacement)

{

{

	struct radix_tree_node *node;

	struct radix_tree_node *node;

	void **pslot;

	void __rcu **pslot;

	void *item;

	void *item;





	VM_BUG_ON(!expected);

	VM_BUG_ON(!expected);
@@ -395,7 +395,7 @@ static bool shmem_confirm_swap(struct address_space *mapping, 
#ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE

#ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE

/* ifdef here to avoid bloating shmem.o when not necessary */

/* 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)

#if defined(CONFIG_SYSFS) || defined(CONFIG_TMPFS)

static int shmem_parse_huge(const char *str)

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)

						pgoff_t start, pgoff_t end)

{

{

	struct radix_tree_iter iter;

	struct radix_tree_iter iter;

	void **slot;

	void __rcu **slot;

	struct page *page;

	struct page *page;

	unsigned long swapped = 0;

	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)

static unsigned long find_swap_entry(struct radix_tree_root *root, void *item)

{

{

	struct radix_tree_iter iter;

	struct radix_tree_iter iter;

	void **slot;

	void __rcu **slot;

	unsigned long found = -1;

	unsigned long found = -1;

	unsigned int checked = 0;

	unsigned int checked = 0;





	rcu_read_lock();

	rcu_read_lock();

	radix_tree_for_each_slot(slot, root, &iter, 0) {

	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;

			found = iter.index;

			break;

			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)

static void shmem_tag_pins(struct address_space *mapping)

{

{

	struct radix_tree_iter iter;

	struct radix_tree_iter iter;

	void **slot;

	void __rcu **slot;

	pgoff_t start;

	pgoff_t start;

	struct page *page;

	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)

static int shmem_wait_for_pins(struct address_space *mapping)

{

{

	struct radix_tree_iter iter;

	struct radix_tree_iter iter;

	void **slot;

	void __rcu **slot;

	pgoff_t start;

	pgoff_t start;

	struct page *page;

	struct page *page;

	int error, scan;

	int error, scan;

CRA Git | Maintained and supported by SUSTech CRA and CCSE