uas: Properly complete inflight commands on bus-reset or disconnect

Before this commit the uas driver would keep track of scsi commands which still
need to have some urbs submitted to the device, and complete this with an
ABORT result code on bus-reset or disconnect, but in flight scsi commands
which have all their urbs submitted, and thus are not part of the work list,
would never get their done callback called.

The problem is killed sense urbs don't have any tag info, so it is impossible
to tell which scsi cmd they belong to, so merely making sure all the urbs
have completed one way or the other is not enough.

This commit fixes this by changing the work list to an inflight list, which
keeps tracks of all inflight scsi cmnds, using the IS_IN_WORK_LIST flag to
determine if actual work needs to be done in uas_do_work(), and by moving
marking all inflight scsi commands as aborted and moving them to the dead list
on bus-reset or disconnect.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>

1 files changed, 21 insertions, 20 deletions

diff --git a/drivers/usb/storage/uas.c b/drivers/usb/storage/uas.c
index e06505c8f6f0..1a188399e090 100644
--- a/drivers/usb/storage/uas.c
+++ b/drivers/usb/storage/uas.c
@@ -58,7 +58,7 @@ struct uas_dev_info {
         struct scsi_cmnd *cmnd;
         spinlock_t lock;
         struct work_struct work;
-        struct list_head work_list;
+        struct list_head inflight_list;
         struct list_head dead_list;
 };
 
@@ -86,7 +86,7 @@ struct uas_cmd_info {
         struct urb *cmd_urb;
         struct urb *data_in_urb;
         struct urb *data_out_urb;
-        struct list_head work;
+        struct list_head inflight;
         struct list_head dead;
 };
 
@@ -125,34 +125,36 @@ static void uas_do_work(struct work_struct *work)
         struct uas_dev_info *devinfo =
                 container_of(work, struct uas_dev_info, work);
         struct uas_cmd_info *cmdinfo;
-        struct uas_cmd_info *temp;
         unsigned long flags;
         int err;
 
         spin_lock_irqsave(&devinfo->lock, flags);
-        list_for_each_entry_safe(cmdinfo, temp, &devinfo->work_list, work) {
+        list_for_each_entry(cmdinfo, &devinfo->inflight_list, inflight) {
                 struct scsi_pointer *scp = (void *)cmdinfo;
                 struct scsi_cmnd *cmnd = container_of(scp, struct scsi_cmnd,
                                                       SCp);
+
+                if (!(cmdinfo->state & IS_IN_WORK_LIST))
+                        continue;
+
                 err = uas_submit_urbs(cmnd, cmnd->device->hostdata, GFP_NOIO);
-                if (!err) {
+                if (!err)
                         cmdinfo->state &= ~IS_IN_WORK_LIST;
-                        list_del(&cmdinfo->work);
-                } else {
+                else
                         schedule_work(&devinfo->work);
-                }
         }
         spin_unlock_irqrestore(&devinfo->lock, flags);
 }
 
-static void uas_abort_work(struct uas_dev_info *devinfo)
+static void uas_abort_inflight(struct uas_dev_info *devinfo)
 {
         struct uas_cmd_info *cmdinfo;
         struct uas_cmd_info *temp;
         unsigned long flags;
 
         spin_lock_irqsave(&devinfo->lock, flags);
-        list_for_each_entry_safe(cmdinfo, temp, &devinfo->work_list, work) {
+        list_for_each_entry_safe(cmdinfo, temp, &devinfo->inflight_list,
+                                 inflight) {
                 struct scsi_pointer *scp = (void *)cmdinfo;
                 struct scsi_cmnd *cmnd = container_of(scp, struct scsi_cmnd,
                                                       SCp);
@@ -160,7 +162,7 @@ static void uas_abort_work(struct uas_dev_info *devinfo)
                 WARN_ON_ONCE(cmdinfo->state & COMMAND_ABORTED);
                 cmdinfo->state |= COMMAND_ABORTED;
                 cmdinfo->state &= ~IS_IN_WORK_LIST;
-                list_del(&cmdinfo->work);
+                list_del(&cmdinfo->inflight);
                 list_add_tail(&cmdinfo->dead, &devinfo->dead_list);
         }
         spin_unlock_irqrestore(&devinfo->lock, flags);
@@ -173,7 +175,6 @@ static void uas_add_work(struct uas_cmd_info *cmdinfo)
         struct uas_dev_info *devinfo = cmnd->device->hostdata;
 
         WARN_ON_ONCE(!spin_is_locked(&devinfo->lock));
-        list_add_tail(&cmdinfo->work, &devinfo->work_list);
         cmdinfo->state |= IS_IN_WORK_LIST;
         schedule_work(&devinfo->work);
 }
@@ -289,7 +290,8 @@ static int uas_try_complete(struct scsi_cmnd *cmnd, const char *caller)
                 scmd_printk(KERN_INFO, cmnd, "abort completed\n");
                 cmnd->result = DID_ABORT << 16;
                 list_del(&cmdinfo->dead);
-        }
+        } else
+                list_del(&cmdinfo->inflight);
         cmnd->scsi_done(cmnd);
         return 0;
 }
@@ -717,6 +719,7 @@ static int uas_queuecommand_lck(struct scsi_cmnd *cmnd,
                 uas_add_work(cmdinfo);
         }
 
+        list_add_tail(&cmdinfo->inflight, &devinfo->inflight_list);
         spin_unlock_irqrestore(&devinfo->lock, flags);
         return 0;
 }
@@ -807,11 +810,9 @@ static int uas_eh_abort_handler(struct scsi_cmnd *cmnd)
         spin_lock_irqsave(&devinfo->lock, flags);
         WARN_ON_ONCE(cmdinfo->state & COMMAND_ABORTED);
         cmdinfo->state |= COMMAND_ABORTED;
+        cmdinfo->state &= ~IS_IN_WORK_LIST;
+        list_del(&cmdinfo->inflight);
         list_add_tail(&cmdinfo->dead, &devinfo->dead_list);
-        if (cmdinfo->state & IS_IN_WORK_LIST) {
-                list_del(&cmdinfo->work);
-                cmdinfo->state &= ~IS_IN_WORK_LIST;
-        }
         if (cmdinfo->state & COMMAND_INFLIGHT) {
                 spin_unlock_irqrestore(&devinfo->lock, flags);
                 ret = uas_eh_task_mgmt(cmnd, "ABORT TASK", TMF_ABORT_TASK);
@@ -847,7 +848,7 @@ static int uas_eh_bus_reset_handler(struct scsi_cmnd *cmnd)
 
         shost_printk(KERN_INFO, sdev->host, "%s start\n", __func__);
         devinfo->resetting = 1;
-        uas_abort_work(devinfo);
+        uas_abort_inflight(devinfo);
         usb_kill_anchored_urbs(&devinfo->cmd_urbs);
         usb_kill_anchored_urbs(&devinfo->sense_urbs);
         usb_kill_anchored_urbs(&devinfo->data_urbs);
@@ -1018,7 +1019,7 @@ static int uas_probe(struct usb_interface *intf, const struct usb_device_id *id)
         init_usb_anchor(&devinfo->data_urbs);
         spin_lock_init(&devinfo->lock);
         INIT_WORK(&devinfo->work, uas_do_work);
-        INIT_LIST_HEAD(&devinfo->work_list);
+        INIT_LIST_HEAD(&devinfo->inflight_list);
         INIT_LIST_HEAD(&devinfo->dead_list);
 
         result = uas_configure_endpoints(devinfo);
@@ -1145,7 +1146,7 @@ static void uas_disconnect(struct usb_interface *intf)
 
         devinfo->resetting = 1;
         cancel_work_sync(&devinfo->work);
-        uas_abort_work(devinfo);
+        uas_abort_inflight(devinfo);
         usb_kill_anchored_urbs(&devinfo->cmd_urbs);
         usb_kill_anchored_urbs(&devinfo->sense_urbs);
         usb_kill_anchored_urbs(&devinfo->data_urbs);