WorkStruct: Separate delayable and non-delayable events.

Separate delayable work items from non-delayable work items be splitting them
into a separate structure (delayed_work), which incorporates a work_struct and
the timer_list removed from work_struct.

The work_struct struct is huge, and this limits it's usefulness.  On a 64-bit
architecture it's nearly 100 bytes in size.  This reduces that by half for the
non-delayable type of event.

Signed-Off-By: David Howells <dhowells@redhat.com>

arch/x86_64/kernel/mce.c

@@ -307,7 +307,7 @@ void mce_log_therm_throt_event(unsigned int cpu, __u64 status)
 
 static int check_interval = 5 * 60; /* 5 minutes */
 static void mcheck_timer(void *data);
-static DECLARE_WORK(mcheck_work, mcheck_timer, NULL);
+static DECLARE_DELAYED_WORK(mcheck_work, mcheck_timer, NULL);
 
 static void mcheck_check_cpu(void *info)
 {

drivers/ata/libata-core.c

@@ -937,12 +937,9 @@ void ata_port_queue_task(struct ata_port *ap, void (*fn)(void *), void *data,
 	if (ap->pflags & ATA_PFLAG_FLUSH_PORT_TASK)
 		return;
 
-	PREPARE_WORK(&ap->port_task, fn, data);
+	PREPARE_DELAYED_WORK(&ap->port_task, fn, data);
 
-	if (!delay)
-		rc = queue_work(ata_wq, &ap->port_task);
-	else
-		rc = queue_delayed_work(ata_wq, &ap->port_task, delay);
+	rc = queue_delayed_work(ata_wq, &ap->port_task, delay);
 
 	/* rc == 0 means that another user is using port task */
 	WARN_ON(rc == 0);
@@ -5320,8 +5317,8 @@ void ata_port_init(struct ata_port *ap, struct ata_host *host,
 	ap->msg_enable = ATA_MSG_DRV | ATA_MSG_ERR | ATA_MSG_WARN;
 #endif
 
-	INIT_WORK(&ap->port_task, NULL, NULL);
-	INIT_WORK(&ap->hotplug_task, ata_scsi_hotplug, ap);
+	INIT_DELAYED_WORK(&ap->port_task, NULL, NULL);
+	INIT_DELAYED_WORK(&ap->hotplug_task, ata_scsi_hotplug, ap);
 	INIT_WORK(&ap->scsi_rescan_task, ata_scsi_dev_rescan, ap);
 	INIT_LIST_HEAD(&ap->eh_done_q);
 	init_waitqueue_head(&ap->eh_wait_q);

drivers/ata/libata-eh.c

@@ -332,7 +332,7 @@ void ata_scsi_error(struct Scsi_Host *host)
 	if (ap->pflags & ATA_PFLAG_LOADING)
 		ap->pflags &= ~ATA_PFLAG_LOADING;
 	else if (ap->pflags & ATA_PFLAG_SCSI_HOTPLUG)
-		queue_work(ata_aux_wq, &ap->hotplug_task);
+		queue_delayed_work(ata_aux_wq, &ap->hotplug_task, 0);
 
 	if (ap->pflags & ATA_PFLAG_RECOVERED)
 		ata_port_printk(ap, KERN_INFO, "EH complete\n");

drivers/char/random.c

@@ -1424,7 +1424,7 @@ static unsigned int ip_cnt;
 
 static void rekey_seq_generator(void *private_);
 
-static DECLARE_WORK(rekey_work, rekey_seq_generator, NULL);
+static DECLARE_DELAYED_WORK(rekey_work, rekey_seq_generator, NULL);
 
 /*
  * Lock avoidance:

drivers/char/tty_io.c

@@ -3580,7 +3580,7 @@ static void initialize_tty_struct(struct tty_struct *tty)
 	tty->overrun_time = jiffies;
 	tty->buf.head = tty->buf.tail = NULL;
 	tty_buffer_init(tty);
-	INIT_WORK(&tty->buf.work, flush_to_ldisc, tty);
+	INIT_DELAYED_WORK(&tty->buf.work, flush_to_ldisc, tty);
 	init_MUTEX(&tty->buf.pty_sem);
 	mutex_init(&tty->termios_mutex);
 	init_waitqueue_head(&tty->write_wait);

fs/aio.c

@@ -227,7 +227,7 @@ static struct kioctx *ioctx_alloc(unsigned nr_events)
 
 	INIT_LIST_HEAD(&ctx->active_reqs);
 	INIT_LIST_HEAD(&ctx->run_list);
-	INIT_WORK(&ctx->wq, aio_kick_handler, ctx);
+	INIT_DELAYED_WORK(&ctx->wq, aio_kick_handler, ctx);
 
 	if (aio_setup_ring(ctx) < 0)
 		goto out_freectx;
@@ -876,7 +876,7 @@ static void aio_kick_handler(void *data)
 	 * we're in a worker thread already, don't use queue_delayed_work,
 	 */
 	if (requeue)
-		queue_work(aio_wq, &ctx->wq);
+		queue_delayed_work(aio_wq, &ctx->wq, 0);
 }
 
 

fs/nfs/client.c

@@ -143,7 +143,7 @@ static struct nfs_client *nfs_alloc_client(const char *hostname,
 	INIT_LIST_HEAD(&clp->cl_state_owners);
 	INIT_LIST_HEAD(&clp->cl_unused);
 	spin_lock_init(&clp->cl_lock);
-	INIT_WORK(&clp->cl_renewd, nfs4_renew_state, clp);
+	INIT_DELAYED_WORK(&clp->cl_renewd, nfs4_renew_state, clp);
 	rpc_init_wait_queue(&clp->cl_rpcwaitq, "NFS client");
 	clp->cl_boot_time = CURRENT_TIME;
 	clp->cl_state = 1 << NFS4CLNT_LEASE_EXPIRED;

fs/nfs/namespace.c

@@ -21,7 +21,8 @@
 static void nfs_expire_automounts(void *list);
 
 LIST_HEAD(nfs_automount_list);
-static DECLARE_WORK(nfs_automount_task, nfs_expire_automounts, &nfs_automount_list);
+static DECLARE_DELAYED_WORK(nfs_automount_task, nfs_expire_automounts,
+			    &nfs_automount_list);
 int nfs_mountpoint_expiry_timeout = 500 * HZ;
 
 static struct vfsmount *nfs_do_submount(const struct vfsmount *mnt_parent,

include/linux/aio.h

@@ -194,7 +194,7 @@ struct kioctx {
 
 	struct aio_ring_info	ring_info;
 
-	struct work_struct	wq;
+	struct delayed_work	wq;
 };
 
 /* prototypes */

include/linux/kbd_kern.h

@@ -158,7 +158,7 @@ static inline void con_schedule_flip(struct tty_struct *t)
 	if (t->buf.tail != NULL)
 		t->buf.tail->commit = t->buf.tail->used;
 	spin_unlock_irqrestore(&t->buf.lock, flags);
-	schedule_work(&t->buf.work);
+	schedule_delayed_work(&t->buf.work, 0);
 }
 
 #endif

include/linux/libata.h

@@ -568,8 +568,8 @@ struct ata_port {
 	struct ata_host		*host;
 	struct device 		*dev;
 
-	struct work_struct	port_task;
-	struct work_struct	hotplug_task;
+	struct delayed_work	port_task;
+	struct delayed_work	hotplug_task;
 	struct work_struct	scsi_rescan_task;
 
 	unsigned int		hsm_task_state;

include/linux/nfs_fs_sb.h

@@ -51,7 +51,7 @@ struct nfs_client {
 
 	unsigned long		cl_lease_time;
 	unsigned long		cl_last_renewal;
-	struct work_struct	cl_renewd;
+	struct delayed_work	cl_renewd;
 
 	struct rpc_wait_queue	cl_rpcwaitq;
 

include/linux/sunrpc/rpc_pipe_fs.h

@@ -30,7 +30,7 @@ struct rpc_inode {
 #define RPC_PIPE_WAIT_FOR_OPEN	1
 	int flags;
 	struct rpc_pipe_ops *ops;
-	struct work_struct queue_timeout;
+	struct delayed_work queue_timeout;
 };
 
 static inline struct rpc_inode *

include/linux/sunrpc/xprt.h

@@ -177,7 +177,7 @@ struct rpc_xprt {
 	unsigned long		connect_timeout,
 				bind_timeout,
 				reestablish_timeout;
-	struct work_struct	connect_worker;
+	struct delayed_work	connect_worker;
 	unsigned short		port;
 
 	/*

include/linux/tty.h

@@ -53,7 +53,7 @@ struct tty_buffer {
 };
 
 struct tty_bufhead {
-	struct work_struct		work;
+	struct delayed_work work;
 	struct semaphore pty_sem;
 	spinlock_t lock;
 	struct tty_buffer *head;	/* Queue head */

include/linux/workqueue.h

@@ -17,6 +17,10 @@ struct work_struct {
 	void (*func)(void *);
 	void *data;
 	void *wq_data;
+};
+
+struct delayed_work {
+	struct work_struct work;
 	struct timer_list timer;
 };
 
@@ -28,32 +32,48 @@ struct execute_work {
         .entry	= { &(n).entry, &(n).entry },			\
 	.func = (f),						\
 	.data = (d),						\
+	}
+
+#define __DELAYED_WORK_INITIALIZER(n, f, d) {			\
+	.work = __WORK_INITIALIZER((n).work, (f), (d)),		\
 	.timer = TIMER_INITIALIZER(NULL, 0, 0),			\
 	}
 
 #define DECLARE_WORK(n, f, d)					\
 	struct work_struct n = __WORK_INITIALIZER(n, f, d)
 
+#define DECLARE_DELAYED_WORK(n, f, d)				\
+	struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, d)
+
 /*
- * initialize a work-struct's func and data pointers:
+ * initialize a work item's function and data pointers
  */
 #define PREPARE_WORK(_work, _func, _data)			\
 	do {							\
-		(_work)->func = _func;				\
-		(_work)->data = _data;				\
+		(_work)->func = (_func);			\
+		(_work)->data = (_data);			\
 	} while (0)
 
+#define PREPARE_DELAYED_WORK(_work, _func, _data)		\
+	PREPARE_WORK(&(_work)->work, (_func), (_data))
+
 /*
- * initialize all of a work-struct:
+ * initialize all of a work item in one go
  */
 #define INIT_WORK(_work, _func, _data)				\
 	do {							\
 		INIT_LIST_HEAD(&(_work)->entry);		\
 		(_work)->pending = 0;				\
 		PREPARE_WORK((_work), (_func), (_data));	\
+	} while (0)
+
+#define INIT_DELAYED_WORK(_work, _func, _data)		\
+	do {							\
+		INIT_WORK(&(_work)->work, (_func), (_data));	\
 		init_timer(&(_work)->timer);			\
 	} while (0)
 
+
 extern struct workqueue_struct *__create_workqueue(const char *name,
 						    int singlethread);
 #define create_workqueue(name) __create_workqueue((name), 0)
@@ -62,24 +82,24 @@ extern struct workqueue_struct *__create_workqueue(const char *name,
 extern void destroy_workqueue(struct workqueue_struct *wq);
 
 extern int FASTCALL(queue_work(struct workqueue_struct *wq, struct work_struct *work));
-extern int FASTCALL(queue_delayed_work(struct workqueue_struct *wq, struct work_struct *work, unsigned long delay));
+extern int FASTCALL(queue_delayed_work(struct workqueue_struct *wq, struct delayed_work *work, unsigned long delay));
 extern int queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
-	struct work_struct *work, unsigned long delay);
+	struct delayed_work *work, unsigned long delay);
 extern void FASTCALL(flush_workqueue(struct workqueue_struct *wq));
 
 extern int FASTCALL(schedule_work(struct work_struct *work));
-extern int FASTCALL(schedule_delayed_work(struct work_struct *work, unsigned long delay));
+extern int FASTCALL(schedule_delayed_work(struct delayed_work *work, unsigned long delay));
 
-extern int schedule_delayed_work_on(int cpu, struct work_struct *work, unsigned long delay);
+extern int schedule_delayed_work_on(int cpu, struct delayed_work *work, unsigned long delay);
 extern int schedule_on_each_cpu(void (*func)(void *info), void *info);
 extern void flush_scheduled_work(void);
 extern int current_is_keventd(void);
 extern int keventd_up(void);
 
 extern void init_workqueues(void);
-void cancel_rearming_delayed_work(struct work_struct *work);
+void cancel_rearming_delayed_work(struct delayed_work *work);
 void cancel_rearming_delayed_workqueue(struct workqueue_struct *,
-				       struct work_struct *);
+				       struct delayed_work *);
 int execute_in_process_context(void (*fn)(void *), void *,
 			       struct execute_work *);
 
@@ -88,13 +108,13 @@ int execute_in_process_context(void (*fn)(void *), void *,
  * function may still be running on return from cancel_delayed_work().  Run
  * flush_scheduled_work() to wait on it.
  */
-static inline int cancel_delayed_work(struct work_struct *work)
+static inline int cancel_delayed_work(struct delayed_work *work)
 {
 	int ret;
 
 	ret = del_timer_sync(&work->timer);
 	if (ret)
-		clear_bit(0, &work->pending);
+		clear_bit(0, &work->work.pending);
 	return ret;
 }