usb/uas: use scsi_host_find_tag() to find command from a tag

BugLink: http://bugs.launchpad.net/bugs/901215

In "usb/uas: use unique tags for all LUNs" we make sure to create unique
tags across all LUNs. This patch uses scsi_host_find_tag() to obtain the
correct command which is associated with the tag.
The following changes are required:
- don't use sdev->current_cmnd anymore
  Since we can have devices which don't support command queueing we must
  ensure that we can tell the two commands apart. Even if a device
  supports comand queuing we send the INQUIRY command "untagged" for
  LUN1 while we can send a tagged command to LUN0 at the same time.
  devinfo->cmnd is used for stashing the one "untagged" command.
- tag number is altered. If stream support is used then the tag number
  must match the stream number. Therefore we can't use tag 0 and must
  start at tag 1.
  In case we have untagged commands (at least the first command) we must
  be able to distinguish between command tag 0 (which becomes 1) and
  untagged command (which becomes curently also 1).
  The following tag numbers are used:
  0: never
  1: for untagged commands (devinfo->cmnd)
  2+: tagged commands.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
(cherry picked from commit 22188f4a933c6e86ac67f52028895c795896492e)

Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Acked-by: Herton Krzesinski <herton.krzesinski@canonical.com>

diff --git a/drivers/usb/storage/uas.c b/drivers/usb/storage/uas.c
index 6974f4b..e2386e8 100644 (file)
--- a/drivers/usb/storage/uas.c
+++ b/drivers/usb/storage/uas.c
@@ -98,6 +98,7 @@ struct uas_dev_info {
        unsigned cmd_pipe, status_pipe, data_in_pipe, data_out_pipe;
        unsigned use_streams:1;
        unsigned uas_sense_old:1;
+       struct scsi_cmnd *cmnd;
 };
 
 enum {
@@ -178,8 +179,6 @@ static void uas_sense(struct urb *urb, struct scsi_cmnd *cmnd)
        }
 
        cmnd->result = sense_iu->status;
-       if (sdev->current_cmnd)
-               sdev->current_cmnd = NULL;
        cmnd->scsi_done(cmnd);
        usb_free_urb(urb);
 }
@@ -205,8 +204,6 @@ static void uas_sense_old(struct urb *urb, struct scsi_cmnd *cmnd)
        }
 
        cmnd->result = sense_iu->status;
-       if (sdev->current_cmnd)
-               sdev->current_cmnd = NULL;
        cmnd->scsi_done(cmnd);
        usb_free_urb(urb);
 }
@@ -230,8 +227,8 @@ static void uas_xfer_data(struct urb *urb, struct scsi_cmnd *cmnd,
 static void uas_stat_cmplt(struct urb *urb)
 {
        struct iu *iu = urb->transfer_buffer;
-       struct scsi_device *sdev = urb->context;
-       struct uas_dev_info *devinfo = sdev->hostdata;
+       struct Scsi_Host *shost = urb->context;
+       struct uas_dev_info *devinfo = (void *)shost->hostdata[0];
        struct scsi_cmnd *cmnd;
        u16 tag;
 
@@ -242,10 +239,10 @@ static void uas_stat_cmplt(struct urb *urb)
        }
 
        tag = be16_to_cpup(&iu->tag) - 1;
-       if (sdev->current_cmnd)
-               cmnd = sdev->current_cmnd;
+       if (tag == 0)
+               cmnd = devinfo->cmnd;
        else
-               cmnd = scsi_find_tag(sdev, tag);
+               cmnd = scsi_host_find_tag(shost, tag - 1);
        if (!cmnd) {
                usb_free_urb(urb);
                return;
@@ -253,6 +250,9 @@ static void uas_stat_cmplt(struct urb *urb)
 
        switch (iu->iu_id) {
        case IU_ID_STATUS:
+               if (devinfo->cmnd == cmnd)
+                       devinfo->cmnd = NULL;
+
                if (urb->actual_length < 16)
                        devinfo->uas_sense_old = 1;
                if (devinfo->uas_sense_old)
@@ -314,7 +314,7 @@ static struct urb *uas_alloc_sense_urb(struct uas_dev_info *devinfo, gfp_t gfp,
                goto free;
 
        usb_fill_bulk_urb(urb, udev, devinfo->status_pipe, iu, sizeof(*iu),
-                                               uas_stat_cmplt, cmnd->device);
+                                               uas_stat_cmplt, cmnd->device->host);
        urb->stream_id = stream_id;
        urb->transfer_flags |= URB_FREE_BUFFER;
  out:
@@ -346,7 +346,7 @@ static struct urb *uas_alloc_cmd_urb(struct uas_dev_info *devinfo, gfp_t gfp,
 
        iu->iu_id = IU_ID_COMMAND;
        if (blk_rq_tagged(cmnd->request))
-               iu->tag = cpu_to_be16(cmnd->request->tag + 1);
+               iu->tag = cpu_to_be16(cmnd->request->tag + 2);
        else
                iu->tag = cpu_to_be16(1);
        iu->prio_attr = UAS_SIMPLE_TAG;
@@ -458,13 +458,13 @@ static int uas_queuecommand_lck(struct scsi_cmnd *cmnd,
 
        BUILD_BUG_ON(sizeof(struct uas_cmd_info) > sizeof(struct scsi_pointer));
 
-       if (!cmdinfo->status_urb && sdev->current_cmnd)
+       if (devinfo->cmnd)
                return SCSI_MLQUEUE_DEVICE_BUSY;
 
        if (blk_rq_tagged(cmnd->request)) {
-               cmdinfo->stream = cmnd->request->tag + 1;
+               cmdinfo->stream = cmnd->request->tag + 2;
        } else {
-               sdev->current_cmnd = cmnd;
+               devinfo->cmnd = cmnd;
                cmdinfo->stream = 1;
        }
 
@@ -565,7 +565,7 @@ static int uas_slave_configure(struct scsi_device *sdev)
 {
        struct uas_dev_info *devinfo = sdev->hostdata;
        scsi_set_tag_type(sdev, MSG_ORDERED_TAG);
-       scsi_activate_tcq(sdev, devinfo->qdepth - 1);
+       scsi_activate_tcq(sdev, devinfo->qdepth - 2);
        return 0;
 }
 
@@ -633,6 +633,7 @@ static void uas_configure_endpoints(struct uas_dev_info *devinfo)
        unsigned i, n_endpoints = intf->cur_altsetting->desc.bNumEndpoints;
 
        devinfo->uas_sense_old = 0;
+       devinfo->cmnd = NULL;
 
        for (i = 0; i < n_endpoints; i++) {
                unsigned char *extra = endpoint[i].extra;
@@ -728,7 +729,7 @@ static int uas_probe(struct usb_interface *intf, const struct usb_device_id *id)
        devinfo->udev = udev;
        uas_configure_endpoints(devinfo);
 
-       result = scsi_init_shared_tag_map(shost, devinfo->qdepth - 1);
+       result = scsi_init_shared_tag_map(shost, devinfo->qdepth - 2);
        if (result)
                goto free;