unsigned ata_exec_internal_sg()

in libata-core.c [1463:1617]

• 110 lines of code
• 22 McCabe index (conditional complexity)

unsigned ata_exec_internal_sg(struct ata_device *dev,
			      struct ata_taskfile *tf, const u8 *cdb,
			      int dma_dir, struct scatterlist *sgl,
			      unsigned int n_elem, unsigned long timeout)
{
	struct ata_link *link = dev->link;
	struct ata_port *ap = link->ap;
	u8 command = tf->command;
	int auto_timeout = 0;
	struct ata_queued_cmd *qc;
	unsigned int preempted_tag;
	u32 preempted_sactive;
	u64 preempted_qc_active;
	int preempted_nr_active_links;
	DECLARE_COMPLETION_ONSTACK(wait);
	unsigned long flags;
	unsigned int err_mask;
	int rc;

	spin_lock_irqsave(ap->lock, flags);

	/* no internal command while frozen */
	if (ap->pflags & ATA_PFLAG_FROZEN) {
		spin_unlock_irqrestore(ap->lock, flags);
		return AC_ERR_SYSTEM;
	}

	/* initialize internal qc */
	qc = __ata_qc_from_tag(ap, ATA_TAG_INTERNAL);

	qc->tag = ATA_TAG_INTERNAL;
	qc->hw_tag = 0;
	qc->scsicmd = NULL;
	qc->ap = ap;
	qc->dev = dev;
	ata_qc_reinit(qc);

	preempted_tag = link->active_tag;
	preempted_sactive = link->sactive;
	preempted_qc_active = ap->qc_active;
	preempted_nr_active_links = ap->nr_active_links;
	link->active_tag = ATA_TAG_POISON;
	link->sactive = 0;
	ap->qc_active = 0;
	ap->nr_active_links = 0;

	/* prepare & issue qc */
	qc->tf = *tf;
	if (cdb)
		memcpy(qc->cdb, cdb, ATAPI_CDB_LEN);

	/* some SATA bridges need us to indicate data xfer direction */
	if (tf->protocol == ATAPI_PROT_DMA && (dev->flags & ATA_DFLAG_DMADIR) &&
	    dma_dir == DMA_FROM_DEVICE)
		qc->tf.feature |= ATAPI_DMADIR;

	qc->flags |= ATA_QCFLAG_RESULT_TF;
	qc->dma_dir = dma_dir;
	if (dma_dir != DMA_NONE) {
		unsigned int i, buflen = 0;
		struct scatterlist *sg;

		for_each_sg(sgl, sg, n_elem, i)
			buflen += sg->length;

		ata_sg_init(qc, sgl, n_elem);
		qc->nbytes = buflen;
	}

	qc->private_data = &wait;
	qc->complete_fn = ata_qc_complete_internal;

	ata_qc_issue(qc);

	spin_unlock_irqrestore(ap->lock, flags);

	if (!timeout) {
		if (ata_probe_timeout)
			timeout = ata_probe_timeout * 1000;
		else {
			timeout = ata_internal_cmd_timeout(dev, command);
			auto_timeout = 1;
		}
	}

	if (ap->ops->error_handler)
		ata_eh_release(ap);

	rc = wait_for_completion_timeout(&wait, msecs_to_jiffies(timeout));

	if (ap->ops->error_handler)
		ata_eh_acquire(ap);

	ata_sff_flush_pio_task(ap);

	if (!rc) {
		spin_lock_irqsave(ap->lock, flags);

		/* We're racing with irq here.  If we lose, the
		 * following test prevents us from completing the qc
		 * twice.  If we win, the port is frozen and will be
		 * cleaned up by ->post_internal_cmd().
		 */
		if (qc->flags & ATA_QCFLAG_ACTIVE) {
			qc->err_mask |= AC_ERR_TIMEOUT;

			if (ap->ops->error_handler)
				ata_port_freeze(ap);
			else
				ata_qc_complete(qc);

			ata_dev_warn(dev, "qc timeout (cmd 0x%x)\n",
				     command);
		}

		spin_unlock_irqrestore(ap->lock, flags);
	}

	/* do post_internal_cmd */
	if (ap->ops->post_internal_cmd)
		ap->ops->post_internal_cmd(qc);

	/* perform minimal error analysis */
	if (qc->flags & ATA_QCFLAG_FAILED) {
		if (qc->result_tf.command & (ATA_ERR | ATA_DF))
			qc->err_mask |= AC_ERR_DEV;

		if (!qc->err_mask)
			qc->err_mask |= AC_ERR_OTHER;

		if (qc->err_mask & ~AC_ERR_OTHER)
			qc->err_mask &= ~AC_ERR_OTHER;
	} else if (qc->tf.command == ATA_CMD_REQ_SENSE_DATA) {
		qc->result_tf.command |= ATA_SENSE;
	}

	/* finish up */
	spin_lock_irqsave(ap->lock, flags);

	*tf = qc->result_tf;
	err_mask = qc->err_mask;

	ata_qc_free(qc);
	link->active_tag = preempted_tag;
	link->sactive = preempted_sactive;
	ap->qc_active = preempted_qc_active;
	ap->nr_active_links = preempted_nr_active_links;

	spin_unlock_irqrestore(ap->lock, flags);

	if ((err_mask & AC_ERR_TIMEOUT) && auto_timeout)
		ata_internal_cmd_timed_out(dev, command);

	return err_mask;
}