Merge tag 'v3.10-rc1' into stable/for-linus-3.10

Linux 3.10-rc1

* tag 'v3.10-rc1': (12273 commits)
  Linux 3.10-rc1
  [SCSI] qla2xxx: Update firmware link in Kconfig file.
  [SCSI] iscsi class, qla4xxx: fix sess/conn refcounting when find fns are used
  [SCSI] sas: unify the pointlessly separated enums sas_dev_type and sas_device_type
  [SCSI] pm80xx: thermal, sas controller config and error handling update
  [SCSI] pm80xx: NCQ error handling changes
  [SCSI] pm80xx: WWN Modification for PM8081/88/89 controllers
  [SCSI] pm80xx: Changed module name and debug messages update
  [SCSI] pm80xx: Firmware flash memory free fix, with addition of new memory region for it
  [SCSI] pm80xx: SPC new firmware changes for device id 0x8081 alone
  [SCSI] pm80xx: Added SPCv/ve specific hardware functionalities and relevant changes in common files
  [SCSI] pm80xx: MSI-X implementation for using 64 interrupts
  [SCSI] pm80xx: Updated common functions common for SPC and SPCv/ve
  [SCSI] pm80xx: Multiple inbound/outbound queue configuration
  [SCSI] pm80xx: Added SPCv/ve specific ids, variables and modify for SPC
  [SCSI] lpfc: fix up Kconfig dependencies
  [SCSI] Handle MLQUEUE busy response in scsi_send_eh_cmnd
  dm cache: set config value
  dm cache: move config fns
  dm thin: generate event when metadata threshold passed
  ...

1 files changed, 16 insertions, 22 deletions

diff --git a/lib/rwsem-spinlock.c b/lib/rwsem-spinlock.c
index 7542afbb22b..9be8a914497 100644
--- a/lib/rwsem-spinlock.c
+++ b/lib/rwsem-spinlock.c
@@ -9,12 +9,15 @@
 #include <linux/sched.h>
 #include <linux/export.h>
 
+enum rwsem_waiter_type {
+	RWSEM_WAITING_FOR_WRITE,
+	RWSEM_WAITING_FOR_READ
+};
+
 struct rwsem_waiter {
 	struct list_head list;
 	struct task_struct *task;
-	unsigned int flags;
-#define RWSEM_WAITING_FOR_READ	0x00000001
-#define RWSEM_WAITING_FOR_WRITE	0x00000002
+	enum rwsem_waiter_type type;
 };
 
 int rwsem_is_locked(struct rw_semaphore *sem)
@@ -67,26 +70,17 @@ __rwsem_do_wake(struct rw_semaphore *sem, int wakewrite)
 
 	waiter = list_entry(sem->wait_list.next, struct rwsem_waiter, list);
 
-	if (!wakewrite) {
-		if (waiter->flags & RWSEM_WAITING_FOR_WRITE)
-			goto out;
-		goto dont_wake_writers;
-	}
-
-	/*
-	 * as we support write lock stealing, we can't set sem->activity
-	 * to -1 here to indicate we get the lock. Instead, we wake it up
-	 * to let it go get it again.
-	 */
-	if (waiter->flags & RWSEM_WAITING_FOR_WRITE) {
-		wake_up_process(waiter->task);
+	if (waiter->type == RWSEM_WAITING_FOR_WRITE) {
+		if (wakewrite)
+			/* Wake up a writer. Note that we do not grant it the
+			 * lock - it will have to acquire it when it runs. */
+			wake_up_process(waiter->task);
 		goto out;
 	}
 
 	/* grant an infinite number of read locks to the front of the queue */
- dont_wake_writers:
 	woken = 0;
-	while (waiter->flags & RWSEM_WAITING_FOR_READ) {
+	do {
 		struct list_head *next = waiter->list.next;
 
 		list_del(&waiter->list);
@@ -96,10 +90,10 @@ __rwsem_do_wake(struct rw_semaphore *sem, int wakewrite)
 		wake_up_process(tsk);
 		put_task_struct(tsk);
 		woken++;
-		if (list_empty(&sem->wait_list))
+		if (next == &sem->wait_list)
 			break;
 		waiter = list_entry(next, struct rwsem_waiter, list);
-	}
+	} while (waiter->type != RWSEM_WAITING_FOR_WRITE);
 
 	sem->activity += woken;
 
@@ -144,7 +138,7 @@ void __sched __down_read(struct rw_semaphore *sem)
 
 	/* set up my own style of waitqueue */
 	waiter.task = tsk;
-	waiter.flags = RWSEM_WAITING_FOR_READ;
+	waiter.type = RWSEM_WAITING_FOR_READ;
 	get_task_struct(tsk);
 
 	list_add_tail(&waiter.list, &sem->wait_list);
@@ -201,7 +195,7 @@ void __sched __down_write_nested(struct rw_semaphore *sem, int subclass)
 	/* set up my own style of waitqueue */
 	tsk = current;
 	waiter.task = tsk;
-	waiter.flags = RWSEM_WAITING_FOR_WRITE;
+	waiter.type = RWSEM_WAITING_FOR_WRITE;
 	list_add_tail(&waiter.list, &sem->wait_list);
 
 	/* wait for someone to release the lock */