libata-core: convert to use cancel_rearming_delayed_work()

We should not use cancel_work_sync(delayed_work->work). This works, but not
good. We can use cancel_rearming_delayed_work(), this also simplifies the
code.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

2 files changed, 4 insertions, 41 deletions

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 5b25311ba885..257fda90e527 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -1283,18 +1283,11 @@ static unsigned int ata_id_xfermask(const u16 *id)
 void ata_port_queue_task(struct ata_port *ap, work_func_t fn, void *data,
                          unsigned long delay)
 {
-        int rc;
-
-        if (ap->pflags & ATA_PFLAG_FLUSH_PORT_TASK)
-                return;
-
         PREPARE_DELAYED_WORK(&ap->port_task, fn);
         ap->port_task_data = data;
 
-        rc = queue_delayed_work(ata_wq, &ap->port_task, delay);
-
-        /* rc == 0 means that another user is using port task */
-        WARN_ON(rc == 0);
+        /* may fail if ata_port_flush_task() in progress */
+        queue_delayed_work(ata_wq, &ap->port_task, delay);
 }
 
 /**
@@ -1309,32 +1302,9 @@ void ata_port_queue_task(struct ata_port *ap, work_func_t fn, void *data,
  */
 void ata_port_flush_task(struct ata_port *ap)
 {
-        unsigned long flags;
-
         DPRINTK("ENTER\n");
 
-        spin_lock_irqsave(ap->lock, flags);
-        ap->pflags |= ATA_PFLAG_FLUSH_PORT_TASK;
-        spin_unlock_irqrestore(ap->lock, flags);
-
-        DPRINTK("flush #1\n");
-        cancel_work_sync(&ap->port_task.work); /* akpm: seems unneeded */
-
-        /*
-         * At this point, if a task is running, it's guaranteed to see
-         * the FLUSH flag; thus, it will never queue pio tasks again.
-         * Cancel and flush.
-         */
-        if (!cancel_delayed_work(&ap->port_task)) {
-                if (ata_msg_ctl(ap))
-                        ata_port_printk(ap, KERN_DEBUG, "%s: flush #2\n",
-                                        __FUNCTION__);
-                cancel_work_sync(&ap->port_task.work);
-        }
-
-        spin_lock_irqsave(ap->lock, flags);
-        ap->pflags &= ~ATA_PFLAG_FLUSH_PORT_TASK;
-        spin_unlock_irqrestore(ap->lock, flags);
+        cancel_rearming_delayed_work(&ap->port_task);
 
         if (ata_msg_ctl(ap))
                 ata_port_printk(ap, KERN_DEBUG, "%s: EXIT\n", __FUNCTION__);
@@ -6557,13 +6527,7 @@ void ata_port_detach(struct ata_port *ap)
         spin_unlock_irqrestore(ap->lock, flags);
 
         ata_port_wait_eh(ap);
-
-        /* Flush hotplug task.  The sequence is similar to
-         * ata_port_flush_task().
-         */
-        cancel_work_sync(&ap->hotplug_task.work); /* akpm: why? */
-        cancel_delayed_work(&ap->hotplug_task);
-        cancel_work_sync(&ap->hotplug_task.work);
+        cancel_rearming_delayed_work(&ap->hotplug_task);
 
  skip_eh:
         /* remove the associated SCSI host */
diff --git a/include/linux/libata.h b/include/linux/libata.h
index a3df64677ac3..bf98d44c8109 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -196,7 +196,6 @@ enum {
         ATA_PFLAG_SCSI_HOTPLUG  = (1 << 6), /* SCSI hotplug scheduled */
         ATA_PFLAG_INITIALIZING  = (1 << 7), /* being initialized, don't touch */
 
-        ATA_PFLAG_FLUSH_PORT_TASK = (1 << 16), /* flush port task */
         ATA_PFLAG_SUSPENDED     = (1 << 17), /* port is suspended (power) */
         ATA_PFLAG_PM_PENDING    = (1 << 18), /* PM operation pending */
         ATA_PFLAG_GTM_VALID     = (1 << 19), /* acpi_gtm data valid */