Add a workaround patch to fix kernel panic after ESATA disk connection

Patches from this directory are applied by 'meta-elphel393/recipes-kernel/linux/linux-xlnx' bitbake recipe. To add a new patch, append SRC_URI variable in the recipe.

Short description of the paches:

libata-eh.c.patch

	This patch is a workaround for the situation when ESATA disk connection leads to kernel panic. Consider the following execution path in driver: libata-core.c:ata_exec_internal_sg -> error during command execution leading to command timeout -> libata-core.c:ata_qc_complete (or ata_port_freeze and finally to the same function) -> libata-core.c:ata_qc_schedule_eh where qc->scsicmd is a NULL pointer by the moment. This patch may not be needed when all hardware/software issues are rectified.

diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c

index d2029a4..3fdf705 100644

--- a/drivers/ata/libata-eh.c

+++ b/drivers/ata/libata-eh.c

@@ -968,7 +968,7 @@ static void ata_eh_set_pending(struct ata_port *ap, int fastdrain)

 void ata_qc_schedule_eh(struct ata_queued_cmd *qc)

 {

 	struct ata_port *ap = qc->ap;

-	struct request_queue *q = qc->scsicmd->device->request_queue;

+	struct request_queue *q;

 	unsigned long flags;

 	WARN_ON(!ap->ops->error_handler);

@@ -981,9 +981,12 @@ void ata_qc_schedule_eh(struct ata_queued_cmd *qc)

 	 * Note that ATA_QCFLAG_FAILED is unconditionally set after

 	 * this function completes.

 	 */

-	spin_lock_irqsave(q->queue_lock, flags);

-	blk_abort_request(qc->scsicmd->request);

-	spin_unlock_irqrestore(q->queue_lock, flags);

+	if (qc->scsicmd != NULL) {

+		q = qc->scsicmd->device->request_queue;

+		spin_lock_irqsave(q->queue_lock, flags);

+		blk_abort_request(qc->scsicmd->request);

+		spin_unlock_irqrestore(q->queue_lock, flags);

+	}

 }

 /**