SCSI fixes on 20150814

This patch consists of 2 libfc fixes causing rare crashes, one iscsi one
 causing a potential hang on shutdown, an I/O blocksize issue which caused a
 regression and a memory leak in scsi-mq.
 
 Signed-off-by: James Bottomley <JBottomley@Odin.com>
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Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi

Pull SCSI fixes from James Bottomley:
 "This has two libfc fixes for bugs causing rare crashes, one iscsi fix
  for a potential hang on shutdown, and a fix for an I/O blocksize issue
  which caused a regression"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  sd: Fix maximum I/O size for BLOCK_PC requests
  libfc: Fix fc_fcp_cleanup_each_cmd()
  libfc: Fix fc_exch_recv_req() error path
  libiscsi: Fix host busy blocking during connection teardown

block/blk-settings.c

@@ -241,8 +241,8 @@ EXPORT_SYMBOL(blk_queue_bounce_limit);
  * Description:
  *    Enables a low level driver to set a hard upper limit,
  *    max_hw_sectors, on the size of requests.  max_hw_sectors is set by
- *    the device driver based upon the combined capabilities of I/O
- *    controller and storage device.
+ *    the device driver based upon the capabilities of the I/O
+ *    controller.
  *
  *    max_sectors is a soft limit imposed by the block layer for
  *    filesystem type requests.  This value can be overridden on a

drivers/scsi/libfc/fc_exch.c

@@ -733,8 +733,6 @@ static bool fc_invoke_resp(struct fc_exch *ep, struct fc_seq *sp,
 	if (resp) {
 		resp(sp, fp, arg);
 		res = true;
-	} else if (!IS_ERR(fp)) {
-		fc_frame_free(fp);
 	}
 
 	spin_lock_bh(&ep->ex_lock);
@@ -1596,7 +1594,8 @@ static void fc_exch_recv_seq_resp(struct fc_exch_mgr *mp, struct fc_frame *fp)
 	 * If new exch resp handler is valid then call that
 	 * first.
 	 */
-	fc_invoke_resp(ep, sp, fp);
+	if (!fc_invoke_resp(ep, sp, fp))
+		fc_frame_free(fp);
 
 	fc_exch_release(ep);
 	return;
@@ -1695,7 +1694,8 @@ static void fc_exch_abts_resp(struct fc_exch *ep, struct fc_frame *fp)
 	fc_exch_hold(ep);
 	if (!rc)
 		fc_exch_delete(ep);
-	fc_invoke_resp(ep, sp, fp);
+	if (!fc_invoke_resp(ep, sp, fp))
+		fc_frame_free(fp);
 	if (has_rec)
 		fc_exch_timer_set(ep, ep->r_a_tov);
 	fc_exch_release(ep);

drivers/scsi/libfc/fc_fcp.c

@@ -1039,11 +1039,26 @@ restart:
 		fc_fcp_pkt_hold(fsp);
 		spin_unlock_irqrestore(&si->scsi_queue_lock, flags);
 
-		if (!fc_fcp_lock_pkt(fsp)) {
+		spin_lock_bh(&fsp->scsi_pkt_lock);
+		if (!(fsp->state & FC_SRB_COMPL)) {
+			fsp->state |= FC_SRB_COMPL;
+			/*
+			 * TODO: dropping scsi_pkt_lock and then reacquiring
+			 * again around fc_fcp_cleanup_cmd() is required,
+			 * since fc_fcp_cleanup_cmd() calls into
+			 * fc_seq_set_resp() and that func preempts cpu using
+			 * schedule. May be schedule and related code should be
+			 * removed instead of unlocking here to avoid scheduling
+			 * while atomic bug.
+			 */
+			spin_unlock_bh(&fsp->scsi_pkt_lock);
+
 			fc_fcp_cleanup_cmd(fsp, error);
+
+			spin_lock_bh(&fsp->scsi_pkt_lock);
 			fc_io_compl(fsp);
-			fc_fcp_unlock_pkt(fsp);
 		}
+		spin_unlock_bh(&fsp->scsi_pkt_lock);
 
 		fc_fcp_pkt_release(fsp);
 		spin_lock_irqsave(&si->scsi_queue_lock, flags);

drivers/scsi/libiscsi.c

@@ -2941,10 +2941,10 @@ void iscsi_conn_teardown(struct iscsi_cls_conn *cls_conn)
 {
 	struct iscsi_conn *conn = cls_conn->dd_data;
 	struct iscsi_session *session = conn->session;
-	unsigned long flags;
 
 	del_timer_sync(&conn->transport_timer);
 
+	mutex_lock(&session->eh_mutex);
 	spin_lock_bh(&session->frwd_lock);
 	conn->c_stage = ISCSI_CONN_CLEANUP_WAIT;
 	if (session->leadconn == conn) {
@@ -2956,28 +2956,6 @@ void iscsi_conn_teardown(struct iscsi_cls_conn *cls_conn)
 	}
 	spin_unlock_bh(&session->frwd_lock);
 
-	/*
-	 * Block until all in-progress commands for this connection
-	 * time out or fail.
-	 */
-	for (;;) {
-		spin_lock_irqsave(session->host->host_lock, flags);
-		if (!atomic_read(&session->host->host_busy)) { /* OK for ERL == 0 */
-			spin_unlock_irqrestore(session->host->host_lock, flags);
-			break;
-		}
-		spin_unlock_irqrestore(session->host->host_lock, flags);
-		msleep_interruptible(500);
-		iscsi_conn_printk(KERN_INFO, conn, "iscsi conn_destroy(): "
-				  "host_busy %d host_failed %d\n",
-				  atomic_read(&session->host->host_busy),
-				  session->host->host_failed);
-		/*
-		 * force eh_abort() to unblock
-		 */
-		wake_up(&conn->ehwait);
-	}
-
 	/* flush queued up work because we free the connection below */
 	iscsi_suspend_tx(conn);
 
@@ -2994,6 +2972,7 @@ void iscsi_conn_teardown(struct iscsi_cls_conn *cls_conn)
 	if (session->leadconn == conn)
 		session->leadconn = NULL;
 	spin_unlock_bh(&session->frwd_lock);
+	mutex_unlock(&session->eh_mutex);
 
 	iscsi_destroy_conn(cls_conn);
 }

drivers/scsi/sd.c

@@ -2770,9 +2770,9 @@ static int sd_revalidate_disk(struct gendisk *disk)
 	max_xfer = sdkp->max_xfer_blocks;
 	max_xfer <<= ilog2(sdp->sector_size) - 9;
 
-	max_xfer = min_not_zero(queue_max_hw_sectors(sdkp->disk->queue),
-				max_xfer);
-	blk_queue_max_hw_sectors(sdkp->disk->queue, max_xfer);
+	sdkp->disk->queue->limits.max_sectors =
+		min_not_zero(queue_max_hw_sectors(sdkp->disk->queue), max_xfer);
+
 	set_capacity(disk, sdkp->capacity);
 	sd_config_write_same(sdkp);
 	kfree(buffer);