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authorLinus Torvalds <torvalds@linux-foundation.org>2019-07-05 11:39:56 +0900
committerLinus Torvalds <torvalds@linux-foundation.org>2019-07-05 11:39:56 +0900
commita5fff14a0c7989fbc8316a43f52aed1804f02ddd (patch)
treed8d4ef6c808868f7d42b6b44cc27b871a22d460a
parentecbe5086adc2876b22c898987d8a20f932de87a9 (diff)
parent8751853091998cd31e9e5f1e8206280155af8921 (diff)
Merge branch 'akpm' (patches from Andrew)
Merge more fixes from Andrew Morton: "5 fixes" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: swap_readpage(): avoid blk_wake_io_task() if !synchronous devres: allow const resource arguments mm/vmscan.c: prevent useless kswapd loops fs/userfaultfd.c: disable irqs for fault_pending and event locks mm/page_alloc.c: fix regression with deferred struct page init
-rw-r--r--fs/userfaultfd.c42
-rw-r--r--include/linux/device.h3
-rw-r--r--lib/devres.c3
-rw-r--r--mm/page_alloc.c3
-rw-r--r--mm/page_io.c13
-rw-r--r--mm/vmscan.c27
6 files changed, 55 insertions, 36 deletions
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index ae0b8b5f69e6..ccbdbd62f0d8 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -40,6 +40,16 @@ enum userfaultfd_state {
/*
* Start with fault_pending_wqh and fault_wqh so they're more likely
* to be in the same cacheline.
+ *
+ * Locking order:
+ * fd_wqh.lock
+ * fault_pending_wqh.lock
+ * fault_wqh.lock
+ * event_wqh.lock
+ *
+ * To avoid deadlocks, IRQs must be disabled when taking any of the above locks,
+ * since fd_wqh.lock is taken by aio_poll() while it's holding a lock that's
+ * also taken in IRQ context.
*/
struct userfaultfd_ctx {
/* waitqueue head for the pending (i.e. not read) userfaults */
@@ -458,7 +468,7 @@ vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason)
blocking_state = return_to_userland ? TASK_INTERRUPTIBLE :
TASK_KILLABLE;
- spin_lock(&ctx->fault_pending_wqh.lock);
+ spin_lock_irq(&ctx->fault_pending_wqh.lock);
/*
* After the __add_wait_queue the uwq is visible to userland
* through poll/read().
@@ -470,7 +480,7 @@ vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason)
* __add_wait_queue.
*/
set_current_state(blocking_state);
- spin_unlock(&ctx->fault_pending_wqh.lock);
+ spin_unlock_irq(&ctx->fault_pending_wqh.lock);
if (!is_vm_hugetlb_page(vmf->vma))
must_wait = userfaultfd_must_wait(ctx, vmf->address, vmf->flags,
@@ -552,13 +562,13 @@ vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason)
* kernel stack can be released after the list_del_init.
*/
if (!list_empty_careful(&uwq.wq.entry)) {
- spin_lock(&ctx->fault_pending_wqh.lock);
+ spin_lock_irq(&ctx->fault_pending_wqh.lock);
/*
* No need of list_del_init(), the uwq on the stack
* will be freed shortly anyway.
*/
list_del(&uwq.wq.entry);
- spin_unlock(&ctx->fault_pending_wqh.lock);
+ spin_unlock_irq(&ctx->fault_pending_wqh.lock);
}
/*
@@ -583,7 +593,7 @@ static void userfaultfd_event_wait_completion(struct userfaultfd_ctx *ctx,
init_waitqueue_entry(&ewq->wq, current);
release_new_ctx = NULL;
- spin_lock(&ctx->event_wqh.lock);
+ spin_lock_irq(&ctx->event_wqh.lock);
/*
* After the __add_wait_queue the uwq is visible to userland
* through poll/read().
@@ -613,15 +623,15 @@ static void userfaultfd_event_wait_completion(struct userfaultfd_ctx *ctx,
break;
}
- spin_unlock(&ctx->event_wqh.lock);
+ spin_unlock_irq(&ctx->event_wqh.lock);
wake_up_poll(&ctx->fd_wqh, EPOLLIN);
schedule();
- spin_lock(&ctx->event_wqh.lock);
+ spin_lock_irq(&ctx->event_wqh.lock);
}
__set_current_state(TASK_RUNNING);
- spin_unlock(&ctx->event_wqh.lock);
+ spin_unlock_irq(&ctx->event_wqh.lock);
if (release_new_ctx) {
struct vm_area_struct *vma;
@@ -918,10 +928,10 @@ wakeup:
* the last page faults that may have been already waiting on
* the fault_*wqh.
*/
- spin_lock(&ctx->fault_pending_wqh.lock);
+ spin_lock_irq(&ctx->fault_pending_wqh.lock);
__wake_up_locked_key(&ctx->fault_pending_wqh, TASK_NORMAL, &range);
__wake_up(&ctx->fault_wqh, TASK_NORMAL, 1, &range);
- spin_unlock(&ctx->fault_pending_wqh.lock);
+ spin_unlock_irq(&ctx->fault_pending_wqh.lock);
/* Flush pending events that may still wait on event_wqh */
wake_up_all(&ctx->event_wqh);
@@ -1134,7 +1144,7 @@ static ssize_t userfaultfd_ctx_read(struct userfaultfd_ctx *ctx, int no_wait,
if (!ret && msg->event == UFFD_EVENT_FORK) {
ret = resolve_userfault_fork(ctx, fork_nctx, msg);
- spin_lock(&ctx->event_wqh.lock);
+ spin_lock_irq(&ctx->event_wqh.lock);
if (!list_empty(&fork_event)) {
/*
* The fork thread didn't abort, so we can
@@ -1180,7 +1190,7 @@ static ssize_t userfaultfd_ctx_read(struct userfaultfd_ctx *ctx, int no_wait,
if (ret)
userfaultfd_ctx_put(fork_nctx);
}
- spin_unlock(&ctx->event_wqh.lock);
+ spin_unlock_irq(&ctx->event_wqh.lock);
}
return ret;
@@ -1219,14 +1229,14 @@ static ssize_t userfaultfd_read(struct file *file, char __user *buf,
static void __wake_userfault(struct userfaultfd_ctx *ctx,
struct userfaultfd_wake_range *range)
{
- spin_lock(&ctx->fault_pending_wqh.lock);
+ spin_lock_irq(&ctx->fault_pending_wqh.lock);
/* wake all in the range and autoremove */
if (waitqueue_active(&ctx->fault_pending_wqh))
__wake_up_locked_key(&ctx->fault_pending_wqh, TASK_NORMAL,
range);
if (waitqueue_active(&ctx->fault_wqh))
__wake_up(&ctx->fault_wqh, TASK_NORMAL, 1, range);
- spin_unlock(&ctx->fault_pending_wqh.lock);
+ spin_unlock_irq(&ctx->fault_pending_wqh.lock);
}
static __always_inline void wake_userfault(struct userfaultfd_ctx *ctx,
@@ -1881,7 +1891,7 @@ static void userfaultfd_show_fdinfo(struct seq_file *m, struct file *f)
wait_queue_entry_t *wq;
unsigned long pending = 0, total = 0;
- spin_lock(&ctx->fault_pending_wqh.lock);
+ spin_lock_irq(&ctx->fault_pending_wqh.lock);
list_for_each_entry(wq, &ctx->fault_pending_wqh.head, entry) {
pending++;
total++;
@@ -1889,7 +1899,7 @@ static void userfaultfd_show_fdinfo(struct seq_file *m, struct file *f)
list_for_each_entry(wq, &ctx->fault_wqh.head, entry) {
total++;
}
- spin_unlock(&ctx->fault_pending_wqh.lock);
+ spin_unlock_irq(&ctx->fault_pending_wqh.lock);
/*
* If more protocols will be added, there will be all shown
diff --git a/include/linux/device.h b/include/linux/device.h
index 848fc71c6ba6..4a295e324ac5 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -704,7 +704,8 @@ extern unsigned long devm_get_free_pages(struct device *dev,
gfp_t gfp_mask, unsigned int order);
extern void devm_free_pages(struct device *dev, unsigned long addr);
-void __iomem *devm_ioremap_resource(struct device *dev, struct resource *res);
+void __iomem *devm_ioremap_resource(struct device *dev,
+ const struct resource *res);
void __iomem *devm_of_iomap(struct device *dev,
struct device_node *node, int index,
diff --git a/lib/devres.c b/lib/devres.c
index 69bed2f38306..6a0e9bd6524a 100644
--- a/lib/devres.c
+++ b/lib/devres.c
@@ -131,7 +131,8 @@ EXPORT_SYMBOL(devm_iounmap);
* if (IS_ERR(base))
* return PTR_ERR(base);
*/
-void __iomem *devm_ioremap_resource(struct device *dev, struct resource *res)
+void __iomem *devm_ioremap_resource(struct device *dev,
+ const struct resource *res)
{
resource_size_t size;
void __iomem *dest_ptr;
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index d66bc8abe0af..8e3bc949ebcc 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1826,7 +1826,8 @@ deferred_grow_zone(struct zone *zone, unsigned int order)
first_deferred_pfn)) {
pgdat->first_deferred_pfn = ULONG_MAX;
pgdat_resize_unlock(pgdat, &flags);
- return true;
+ /* Retry only once. */
+ return first_deferred_pfn != ULONG_MAX;
}
/*
diff --git a/mm/page_io.c b/mm/page_io.c
index 189415852077..a39aac2f8c8d 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -137,8 +137,10 @@ out:
unlock_page(page);
WRITE_ONCE(bio->bi_private, NULL);
bio_put(bio);
- blk_wake_io_task(waiter);
- put_task_struct(waiter);
+ if (waiter) {
+ blk_wake_io_task(waiter);
+ put_task_struct(waiter);
+ }
}
int generic_swapfile_activate(struct swap_info_struct *sis,
@@ -395,11 +397,12 @@ int swap_readpage(struct page *page, bool synchronous)
* Keep this task valid during swap readpage because the oom killer may
* attempt to access it in the page fault retry time check.
*/
- get_task_struct(current);
- bio->bi_private = current;
bio_set_op_attrs(bio, REQ_OP_READ, 0);
- if (synchronous)
+ if (synchronous) {
bio->bi_opf |= REQ_HIPRI;
+ get_task_struct(current);
+ bio->bi_private = current;
+ }
count_vm_event(PSWPIN);
bio_get(bio);
qc = submit_bio(bio);
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 7889f583ced9..910e02c793ff 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -3644,19 +3644,18 @@ out:
}
/*
- * pgdat->kswapd_classzone_idx is the highest zone index that a recent
- * allocation request woke kswapd for. When kswapd has not woken recently,
- * the value is MAX_NR_ZONES which is not a valid index. This compares a
- * given classzone and returns it or the highest classzone index kswapd
- * was recently woke for.
+ * The pgdat->kswapd_classzone_idx is used to pass the highest zone index to be
+ * reclaimed by kswapd from the waker. If the value is MAX_NR_ZONES which is not
+ * a valid index then either kswapd runs for first time or kswapd couldn't sleep
+ * after previous reclaim attempt (node is still unbalanced). In that case
+ * return the zone index of the previous kswapd reclaim cycle.
*/
static enum zone_type kswapd_classzone_idx(pg_data_t *pgdat,
- enum zone_type classzone_idx)
+ enum zone_type prev_classzone_idx)
{
if (pgdat->kswapd_classzone_idx == MAX_NR_ZONES)
- return classzone_idx;
-
- return max(pgdat->kswapd_classzone_idx, classzone_idx);
+ return prev_classzone_idx;
+ return pgdat->kswapd_classzone_idx;
}
static void kswapd_try_to_sleep(pg_data_t *pgdat, int alloc_order, int reclaim_order,
@@ -3797,7 +3796,7 @@ kswapd_try_sleep:
/* Read the new order and classzone_idx */
alloc_order = reclaim_order = pgdat->kswapd_order;
- classzone_idx = kswapd_classzone_idx(pgdat, 0);
+ classzone_idx = kswapd_classzone_idx(pgdat, classzone_idx);
pgdat->kswapd_order = 0;
pgdat->kswapd_classzone_idx = MAX_NR_ZONES;
@@ -3851,8 +3850,12 @@ void wakeup_kswapd(struct zone *zone, gfp_t gfp_flags, int order,
if (!cpuset_zone_allowed(zone, gfp_flags))
return;
pgdat = zone->zone_pgdat;
- pgdat->kswapd_classzone_idx = kswapd_classzone_idx(pgdat,
- classzone_idx);
+
+ if (pgdat->kswapd_classzone_idx == MAX_NR_ZONES)
+ pgdat->kswapd_classzone_idx = classzone_idx;
+ else
+ pgdat->kswapd_classzone_idx = max(pgdat->kswapd_classzone_idx,
+ classzone_idx);
pgdat->kswapd_order = max(pgdat->kswapd_order, order);
if (!waitqueue_active(&pgdat->kswapd_wait))
return;