sg: fix EWOULDBLOCK errors with scsi-mq

			return -ENOMEM;

	}

	rq = blk_get_request(q, rw, GFP_ATOMIC);

	/*

	 * NOTE

	 *

	 * With scsi-mq enabled, there are a fixed number of preallocated

	 * requests equal in number to shost->can_queue.  If all of the

	 * preallocated requests are already in use, then using GFP_ATOMIC with

	 * blk_get_request() will return -EWOULDBLOCK, whereas using GFP_KERNEL

	 * will cause blk_get_request() to sleep until an active command

	 * completes, freeing up a request.  Neither option is ideal, but

	 * GFP_KERNEL is the better choice to prevent userspace from getting an

	 * unexpected EWOULDBLOCK.

	 *

	 * With scsi-mq disabled, blk_get_request() with GFP_KERNEL usually

	 * does not sleep except under memory pressure.

	 */

	rq = blk_get_request(q, rw, GFP_KERNEL);

	if (IS_ERR(rq)) {

		kfree(long_cmdp);

		return PTR_ERR(rq);