#include <linux/idr.h>
#include <linux/hdreg.h>
#include <linux/delay.h>
+#include <linux/wait.h>
#include <trace/events/block.h>
#define DMF_NOFLUSH_SUSPENDING 5
#define DMF_MERGE_IS_OPTIONAL 6
#define DMF_DEFERRED_REMOVE 7
+#define DMF_SUSPENDED_INTERNALLY 8
/*
* A dummy definition to make RCU happy.
}
/*
- * We need to be able to change a mapping table under a mounted
- * filesystem. For example we might want to move some data in
- * the background. Before the table can be swapped with
- * dm_bind_table, dm_suspend must be called to flush any in
- * flight bios and ensure that any further io gets deferred.
- */
-/*
- * Suspend mechanism in request-based dm.
- *
- * 1. Flush all I/Os by lock_fs() if needed.
- * 2. Stop dispatching any I/O by stopping the request_queue.
- * 3. Wait for all in-flight I/Os to be completed or requeued.
+ * If __dm_suspend returns 0, the device is completely quiescent
+ * now. There is no request-processing activity. All new requests
+ * are being added to md->deferred list.
*
- * To abort suspend, start the request_queue.
+ * Caller must hold md->suspend_lock
*/
-int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
+static int __dm_suspend(struct mapped_device *md, struct dm_table *map,
+ unsigned suspend_flags, int interruptible)
{
- struct dm_table *map = NULL;
- int r = 0;
- int do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG ? 1 : 0;
- int noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG ? 1 : 0;
-
- mutex_lock(&md->suspend_lock);
-
- if (dm_suspended_md(md)) {
- r = -EINVAL;
- goto out_unlock;
- }
-
- map = rcu_dereference(md->map);
+ bool do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG;
+ bool noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG;
+ int r;
/*
* DMF_NOFLUSH_SUSPENDING must be set before presuspend.
r = lock_fs(md);
if (r) {
dm_table_presuspend_undo_targets(map);
- goto out_unlock;
+ return r;
}
}
* We call dm_wait_for_completion to wait for all existing requests
* to finish.
*/
- r = dm_wait_for_completion(md, TASK_INTERRUPTIBLE);
+ r = dm_wait_for_completion(md, interruptible);
if (noflush)
clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
unlock_fs(md);
dm_table_presuspend_undo_targets(map);
- goto out_unlock; /* pushback list is already flushed, so skip flush */
+ /* pushback list is already flushed, so skip flush */
}
- /*
- * If dm_wait_for_completion returned 0, the device is completely
- * quiescent now. There is no request-processing activity. All new
- * requests are being added to md->deferred list.
- */
+ return r;
+}
+
+/*
+ * We need to be able to change a mapping table under a mounted
+ * filesystem. For example we might want to move some data in
+ * the background. Before the table can be swapped with
+ * dm_bind_table, dm_suspend must be called to flush any in
+ * flight bios and ensure that any further io gets deferred.
+ */
+/*
+ * Suspend mechanism in request-based dm.
+ *
+ * 1. Flush all I/Os by lock_fs() if needed.
+ * 2. Stop dispatching any I/O by stopping the request_queue.
+ * 3. Wait for all in-flight I/Os to be completed or requeued.
+ *
+ * To abort suspend, start the request_queue.
+ */
+int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
+{
+ struct dm_table *map = NULL;
+ int r = 0;
+
+retry:
+ mutex_lock_nested(&md->suspend_lock, SINGLE_DEPTH_NESTING);
+
+ if (dm_suspended_md(md)) {
+ r = -EINVAL;
+ goto out_unlock;
+ }
+
+ if (dm_suspended_internally_md(md)) {
+ /* already internally suspended, wait for internal resume */
+ mutex_unlock(&md->suspend_lock);
+ r = wait_on_bit(&md->flags, DMF_SUSPENDED_INTERNALLY, TASK_INTERRUPTIBLE);
+ if (r)
+ return r;
+ goto retry;
+ }
+
+ map = rcu_dereference(md->map);
+
+ r = __dm_suspend(md, map, suspend_flags, TASK_INTERRUPTIBLE);
+ if (r)
+ goto out_unlock;
set_bit(DMF_SUSPENDED, &md->flags);
return r;
}
+static int __dm_resume(struct mapped_device *md, struct dm_table *map)
+{
+ if (map) {
+ int r = dm_table_resume_targets(map);
+ if (r)
+ return r;
+ }
+
+ dm_queue_flush(md);
+
+ /*
+ * Flushing deferred I/Os must be done after targets are resumed
+ * so that mapping of targets can work correctly.
+ * Request-based dm is queueing the deferred I/Os in its request_queue.
+ */
+ if (dm_request_based(md))
+ start_queue(md->queue);
+
+ unlock_fs(md);
+
+ return 0;
+}
+
int dm_resume(struct mapped_device *md)
{
int r = -EINVAL;
struct dm_table *map = NULL;
- mutex_lock(&md->suspend_lock);
+retry:
+ mutex_lock_nested(&md->suspend_lock, SINGLE_DEPTH_NESTING);
+
if (!dm_suspended_md(md))
goto out;
+ if (dm_suspended_internally_md(md)) {
+ /* already internally suspended, wait for internal resume */
+ mutex_unlock(&md->suspend_lock);
+ r = wait_on_bit(&md->flags, DMF_SUSPENDED_INTERNALLY, TASK_INTERRUPTIBLE);
+ if (r)
+ return r;
+ goto retry;
+ }
+
map = rcu_dereference(md->map);
if (!map || !dm_table_get_size(map))
goto out;
- r = dm_table_resume_targets(map);
+ r = __dm_resume(md, map);
if (r)
goto out;
- dm_queue_flush(md);
-
- /*
- * Flushing deferred I/Os must be done after targets are resumed
- * so that mapping of targets can work correctly.
- * Request-based dm is queueing the deferred I/Os in its request_queue.
- */
- if (dm_request_based(md))
- start_queue(md->queue);
-
- unlock_fs(md);
-
clear_bit(DMF_SUSPENDED, &md->flags);
r = 0;
* Internal suspend/resume works like userspace-driven suspend. It waits
* until all bios finish and prevents issuing new bios to the target drivers.
* It may be used only from the kernel.
- *
- * Internal suspend holds md->suspend_lock, which prevents interaction with
- * userspace-driven suspend.
*/
-void dm_internal_suspend(struct mapped_device *md)
+static void __dm_internal_suspend(struct mapped_device *md, unsigned suspend_flags)
{
- mutex_lock(&md->suspend_lock);
+ struct dm_table *map = NULL;
+
+ if (dm_suspended_internally_md(md))
+ return; /* nested internal suspend */
+
+ if (dm_suspended_md(md)) {
+ set_bit(DMF_SUSPENDED_INTERNALLY, &md->flags);
+ return; /* nest suspend */
+ }
+
+ map = rcu_dereference(md->map);
+
+ /*
+ * Using TASK_UNINTERRUPTIBLE because only NOFLUSH internal suspend is
+ * supported. Properly supporting a TASK_INTERRUPTIBLE internal suspend
+ * would require changing .presuspend to return an error -- avoid this
+ * until there is a need for more elaborate variants of internal suspend.
+ */
+ (void) __dm_suspend(md, map, suspend_flags, TASK_UNINTERRUPTIBLE);
+
+ set_bit(DMF_SUSPENDED_INTERNALLY, &md->flags);
+
+ dm_table_postsuspend_targets(map);
+}
+
+static void __dm_internal_resume(struct mapped_device *md)
+{
+ if (!dm_suspended_internally_md(md))
+ return; /* resume from nested internal suspend */
+
if (dm_suspended_md(md))
+ goto done; /* resume from nested suspend */
+
+ /*
+ * NOTE: existing callers don't need to call dm_table_resume_targets
+ * (which may fail -- so best to avoid it for now by passing NULL map)
+ */
+ (void) __dm_resume(md, NULL);
+
+done:
+ clear_bit(DMF_SUSPENDED_INTERNALLY, &md->flags);
+ smp_mb__after_atomic();
+ wake_up_bit(&md->flags, DMF_SUSPENDED_INTERNALLY);
+}
+
+void dm_internal_suspend_noflush(struct mapped_device *md)
+{
+ mutex_lock(&md->suspend_lock);
+ __dm_internal_suspend(md, DM_SUSPEND_NOFLUSH_FLAG);
+ mutex_unlock(&md->suspend_lock);
+}
+EXPORT_SYMBOL_GPL(dm_internal_suspend_noflush);
+
+void dm_internal_resume(struct mapped_device *md)
+{
+ mutex_lock(&md->suspend_lock);
+ __dm_internal_resume(md);
+ mutex_unlock(&md->suspend_lock);
+}
+EXPORT_SYMBOL_GPL(dm_internal_resume);
+
+/*
+ * Fast variants of internal suspend/resume hold md->suspend_lock,
+ * which prevents interaction with userspace-driven suspend.
+ */
+
+void dm_internal_suspend_fast(struct mapped_device *md)
+{
+ mutex_lock(&md->suspend_lock);
+ if (dm_suspended_md(md) || dm_suspended_internally_md(md))
return;
set_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
dm_wait_for_completion(md, TASK_UNINTERRUPTIBLE);
}
-void dm_internal_resume(struct mapped_device *md)
+void dm_internal_resume_fast(struct mapped_device *md)
{
- if (dm_suspended_md(md))
+ if (dm_suspended_md(md) || dm_suspended_internally_md(md))
goto done;
dm_queue_flush(md);
return test_bit(DMF_SUSPENDED, &md->flags);
}
+int dm_suspended_internally_md(struct mapped_device *md)
+{
+ return test_bit(DMF_SUSPENDED_INTERNALLY, &md->flags);
+}
+
int dm_test_deferred_remove_flag(struct mapped_device *md)
{
return test_bit(DMF_DEFERRED_REMOVE, &md->flags);
projects / karo-tx-linux.git / commitdiff