[SCSI] ipr: Fix a race on multiple configuration changes

In a multiple configuration change scenario a remove notification can be
followed by an immediate add notification for the same device, which
will cause the device to be removed but never added back. This patch
fixes the problem by ensuring that in such situations the device will be
added back.

Signed-off-by: Kleber Sacilotto de Souza <klebers@linux.vnet.ibm.com>
Acked-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

diff --git a/drivers/scsi/ipr.c b/drivers/scsi/ipr.c
index a8e24f06b8d8aab255df1bde40364f92e2d9b5ad..14857679f4e966854559a9122d5dda98312b0fb5 100644 (file)
--- a/drivers/scsi/ipr.c
+++ b/drivers/scsi/ipr.c
@@ -1301,7 +1301,7 @@ static void ipr_handle_config_change(struct ipr_ioa_cfg *ioa_cfg,
                        ipr_clear_res_target(res);
                        list_move_tail(&res->queue, &ioa_cfg->free_res_q);
                }
-       } else if (!res->sdev) {
+       } else if (!res->sdev || res->del_from_ml) {
                res->add_to_ml = 1;
                if (ioa_cfg->allow_ml_add_del)
                        schedule_work(&ioa_cfg->work_q);
@@ -3104,7 +3104,10 @@ restart:
                                did_work = 1;
                                sdev = res->sdev;
                                if (!scsi_device_get(sdev)) {
-                                       list_move_tail(&res->queue, &ioa_cfg->free_res_q);
+                                       if (!res->add_to_ml)
+                                               list_move_tail(&res->queue, &ioa_cfg->free_res_q);
+                                       else
+                                               res->del_from_ml = 0;
                                        spin_unlock_irqrestore(ioa_cfg->host->host_lock, lock_flags);
                                        scsi_remove_device(sdev);
                                        scsi_device_put(sdev);