[SCSI] add flag to skip the runtime PM calls on the host

With previous change, now the ata port runtime suspend will happen as:

disk suspend --> scsi target suspend --> scsi host suspend --> ata port
suspend

ata port(parent device) suspend need to schedule scsi EH which will resume
scsi host(child device). Then the child device resume will in turn make
parent device resume first. This is kind of recursive.

This patch adds a new flag Scsi_Host::eh_noresume.
ata port will set this flag to skip the runtime PM calls on scsi host.

Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index dc6131e6a1ba2d40fe32504f1cb0e0f8d8b41def..5f84a148eb142417d9e296191329a6126e89ef4a 100644 (file)
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -1812,7 +1812,7 @@ int scsi_error_handler(void *data)
                 * what we need to do to get it up and online again (if we can).
                 * If we fail, we end up taking the thing offline.
                 */
-               if (scsi_autopm_get_host(shost) != 0) {
+               if (!shost->eh_noresume && scsi_autopm_get_host(shost) != 0) {
                        SCSI_LOG_ERROR_RECOVERY(1,
                                printk(KERN_ERR "Error handler scsi_eh_%d "
                                                "unable to autoresume\n",
@@ -1833,7 +1833,8 @@ int scsi_error_handler(void *data)
                 * which are still online.
                 */
                scsi_restart_operations(shost);
-               scsi_autopm_put_host(shost);
+               if (!shost->eh_noresume)
+                       scsi_autopm_put_host(shost);
                set_current_state(TASK_INTERRUPTIBLE);
        }
        __set_current_state(TASK_RUNNING);

diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index 50266c9405fced26eb7a48f386d1889c1f3a6253..5f7d5b3b1c6eaa82c73b3ffcf85321d26f1c705b 100644 (file)
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -669,6 +669,9 @@ struct Scsi_Host {
        /* Asynchronous scan in progress */
        unsigned async_scan:1;
 
+       /* Don't resume host in EH */
+       unsigned eh_noresume:1;
+
        /*
         * Optional work queue to be utilized by the transport
         */