From: Oleg Nesterov 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 Signed-off-by: Andrew Morton --- drivers/ata/libata-core.c | 44 +++--------------------------------- include/linux/libata.h | 1 2 files changed, 4 insertions(+), 41 deletions(-) diff -puN drivers/ata/libata-core.c~libata-core-convert-to-use-cancel_rearming_delayed_work drivers/ata/libata-core.c --- a/drivers/ata/libata-core.c~libata-core-convert-to-use-cancel_rearming_delayed_work +++ a/drivers/ata/libata-core.c @@ -1294,18 +1294,11 @@ static unsigned int ata_id_xfermask(cons 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); } /** @@ -1320,32 +1313,9 @@ void ata_port_queue_task(struct ata_port */ 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__); @@ -6499,13 +6469,7 @@ 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 -puN include/linux/libata.h~libata-core-convert-to-use-cancel_rearming_delayed_work include/linux/libata.h --- a/include/linux/libata.h~libata-core-convert-to-use-cancel_rearming_delayed_work +++ a/include/linux/libata.h @@ -192,7 +192,6 @@ 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 */ _