isci: Qualify when the host lock is managed for STP/SATA callbacks.

In the case of internal discovery related STP/SATA I/O started
through sas_execute_task the host lock is not taken by libsas before
calling lldd_execute_task, so the lock should not be managed before
calling back to libsas through task->task_done or sas_task_abort.

Signed-off-by: Jeff Skirvin <jeffrey.d.skirvin@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 37 insertions, 0 deletions

diff --git a/drivers/scsi/isci/task.h b/drivers/scsi/isci/task.h
index d7cb6fe268c..c5afd1cfbde 100644
--- a/drivers/scsi/isci/task.h
+++ b/drivers/scsi/isci/task.h
@@ -56,6 +56,8 @@
 #if !defined(_ISCI_TASK_H_)
 #define _ISCI_TASK_H_
 
+#include <scsi/sas_ata.h>
+
 struct isci_request;
 struct isci_host;
 
@@ -332,5 +334,40 @@ isci_task_set_completion_status(
         return task_notification_selection;
 
 }
+/**
+* isci_execpath_callback() - This function is called from the task
+* execute path when the task needs to callback libsas about the submit-time
+* task failure.  The callback occurs either through the task's done function
+* or through sas_task_abort.  In the case of regular non-discovery SATA/STP I/O
+* requests, libsas takes the host lock before calling execute task.  Therefore
+* in this situation the host lock must be managed before calling the func.
+*
+* @ihost: This parameter is the controller to which the I/O request was sent.
+* @task: This parameter is the I/O request.
+* @func: This parameter is the function to call in the correct context.
+* @status: This parameter is the status code for the completed task.
+*
+*/
+static inline void isci_execpath_callback(
+        struct isci_host *ihost,
+        struct sas_task  *task,
+        void (*func)(struct sas_task *))
+{
+        unsigned long flags;
+
+        if (dev_is_sata(task->dev) && task->uldd_task) {
+                /* Since we are still in the submit path, and since
+                * libsas takes the host lock on behalf of SATA
+                * devices before I/O starts (in the non-discovery case),
+                * we need to unlock before we can call the callback function.
+                */
+                raw_local_irq_save(flags);
+                spin_unlock(ihost->shost->host_lock);
+                func(task);
+                spin_lock(ihost->shost->host_lock);
+                raw_local_irq_restore(flags);
+        } else
+                func(task);
+}
 
 #endif /* !defined(_SCI_TASK_H_) */