libata: fix shutdown warning message printing

Unlocking ap->lock and ssleeping don't work because SCSI commands can
be issued from completion path without context.  Reimplement delayed
completion by allowing translation functions to override
qc->scsidone(), storing the original completion function to
scmd->scsi_done() and overriding qc->scsidone() with a function which
schedules delayed invocation of scmd->scsi_done().

This isn't pretty at all but all the ugly parts are thankfully
contained in the stop translation path where the compat feature is
implemented.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index dd81fa7..07b5a3d 100644 (file)
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -893,6 +893,23 @@ int ata_scsi_change_queue_depth(struct scsi_device *sdev, int queue_depth)
        return queue_depth;
 }
 
+/* XXX: for ata_spindown_compat */
+static void ata_delayed_done_timerfn(unsigned long arg)
+{
+       struct scsi_cmnd *scmd = (void *)arg;
+
+       scmd->scsi_done(scmd);
+}
+
+/* XXX: for ata_spindown_compat */
+static void ata_delayed_done(struct scsi_cmnd *scmd)
+{
+       static struct timer_list timer;
+
+       setup_timer(&timer, ata_delayed_done_timerfn, (unsigned long)scmd);
+       mod_timer(&timer, jiffies + 5 * HZ);
+}
+
 /**
  *     ata_scsi_start_stop_xlat - Translate SCSI START STOP UNIT command
  *     @qc: Storage for translated ATA taskfile
@@ -952,19 +969,21 @@ static unsigned int ata_scsi_start_stop_xlat(struct ata_queued_cmd *qc)
                if (ata_spindown_compat &&
                    (system_state == SYSTEM_HALT ||
                     system_state == SYSTEM_POWER_OFF)) {
-                       static int warned = 0;
+                       static unsigned long warned = 0;
 
-                       if (!warned) {
-                               spin_unlock_irq(qc->ap->lock);
+                       if (!test_and_set_bit(0, &warned)) {
                                ata_dev_printk(qc->dev, KERN_WARNING,
                                        "DISK MIGHT NOT BE SPUN DOWN PROPERLY. "
                                        "UPDATE SHUTDOWN UTILITY\n");
                                ata_dev_printk(qc->dev, KERN_WARNING,
                                        "For more info, visit "
                                        "http://linux-ata.org/shutdown.html\n");
-                               warned = 1;
-                               ssleep(5);
-                               spin_lock_irq(qc->ap->lock);
+
+                               /* ->scsi_done is not used, use it for
+                                * delayed completion.
+                                */
+                               scmd->scsi_done = qc->scsidone;
+                               qc->scsidone = ata_delayed_done;
                        }
                        scmd->result = SAM_STAT_GOOD;
                        return 1;
@@ -1488,14 +1507,14 @@ static int ata_scsi_translate(struct ata_device *dev, struct scsi_cmnd *cmd,
 
 early_finish:
         ata_qc_free(qc);
-       done(cmd);
+       qc->scsidone(cmd);
        DPRINTK("EXIT - early finish (good or error)\n");
        return 0;
 
 err_did:
        ata_qc_free(qc);
        cmd->result = (DID_ERROR << 16);
-       done(cmd);
+       qc->scsidone(cmd);
 err_mem:
        DPRINTK("EXIT - internal\n");
        return 0;