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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>
This commit is contained in:
Mike Kravetz 2018-06-07 17:05:53 -07:00 committed by Linus Torvalds
parent c0265342bf
commit 5b9c98f308
1 changed files with 13 additions and 7 deletions
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20
mm/shmem.c
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@ -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;