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Diffstat (limited to 'mm/swapfile.c')
-rw-r--r--mm/swapfile.c31
1 files changed, 18 insertions, 13 deletions
diff --git a/mm/swapfile.c b/mm/swapfile.c
index eb410d3c8de8..12f59e641b5e 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -672,7 +672,7 @@ static void swap_range_alloc(struct swap_info_struct *si, unsigned long offset,
if (offset == si->lowest_bit)
si->lowest_bit += nr_entries;
if (end == si->highest_bit)
- si->highest_bit -= nr_entries;
+ WRITE_ONCE(si->highest_bit, si->highest_bit - nr_entries);
si->inuse_pages += nr_entries;
if (si->inuse_pages == si->pages) {
si->lowest_bit = si->max;
@@ -705,7 +705,7 @@ static void swap_range_free(struct swap_info_struct *si, unsigned long offset,
if (end > si->highest_bit) {
bool was_full = !si->highest_bit;
- si->highest_bit = end;
+ WRITE_ONCE(si->highest_bit, end);
if (was_full && (si->flags & SWP_WRITEOK))
add_to_avail_list(si);
}
@@ -870,7 +870,7 @@ checks:
else
goto done;
}
- si->swap_map[offset] = usage;
+ WRITE_ONCE(si->swap_map[offset], usage);
inc_cluster_info_page(si, si->cluster_info, offset);
unlock_cluster(ci);
@@ -929,12 +929,13 @@ done:
scan:
spin_unlock(&si->lock);
- while (++offset <= si->highest_bit) {
- if (!si->swap_map[offset]) {
+ while (++offset <= READ_ONCE(si->highest_bit)) {
+ if (data_race(!si->swap_map[offset])) {
spin_lock(&si->lock);
goto checks;
}
- if (vm_swap_full() && si->swap_map[offset] == SWAP_HAS_CACHE) {
+ if (vm_swap_full() &&
+ READ_ONCE(si->swap_map[offset]) == SWAP_HAS_CACHE) {
spin_lock(&si->lock);
goto checks;
}
@@ -946,11 +947,12 @@ scan:
}
offset = si->lowest_bit;
while (offset < scan_base) {
- if (!si->swap_map[offset]) {
+ if (data_race(!si->swap_map[offset])) {
spin_lock(&si->lock);
goto checks;
}
- if (vm_swap_full() && si->swap_map[offset] == SWAP_HAS_CACHE) {
+ if (vm_swap_full() &&
+ READ_ONCE(si->swap_map[offset]) == SWAP_HAS_CACHE) {
spin_lock(&si->lock);
goto checks;
}
@@ -1149,7 +1151,7 @@ static struct swap_info_struct *__swap_info_get(swp_entry_t entry)
p = swp_swap_info(entry);
if (!p)
goto bad_nofile;
- if (!(p->flags & SWP_USED))
+ if (data_race(!(p->flags & SWP_USED)))
goto bad_device;
offset = swp_offset(entry);
if (offset >= p->max)
@@ -1175,7 +1177,7 @@ static struct swap_info_struct *_swap_info_get(swp_entry_t entry)
p = __swap_info_get(entry);
if (!p)
goto out;
- if (!p->swap_map[swp_offset(entry)])
+ if (data_race(!p->swap_map[swp_offset(entry)]))
goto bad_free;
return p;
@@ -1244,7 +1246,10 @@ static unsigned char __swap_entry_free_locked(struct swap_info_struct *p,
}
usage = count | has_cache;
- p->swap_map[offset] = usage ? : SWAP_HAS_CACHE;
+ if (usage)
+ WRITE_ONCE(p->swap_map[offset], usage);
+ else
+ WRITE_ONCE(p->swap_map[offset], SWAP_HAS_CACHE);
return usage;
}
@@ -1296,7 +1301,7 @@ struct swap_info_struct *get_swap_device(swp_entry_t entry)
goto bad_nofile;
rcu_read_lock();
- if (!(si->flags & SWP_VALID))
+ if (data_race(!(si->flags & SWP_VALID)))
goto unlock_out;
offset = swp_offset(entry);
if (offset >= si->max)
@@ -3484,7 +3489,7 @@ static int __swap_duplicate(swp_entry_t entry, unsigned char usage)
} else
err = -ENOENT; /* unused swap entry */
- p->swap_map[offset] = count | has_cache;
+ WRITE_ONCE(p->swap_map[offset], count | has_cache);
unlock_out:
unlock_cluster_or_swap_info(p, ci);