[PATCH] libata: separate out libata-eh.c

A lot of EH codes are about to be added to libata.  Separate out
libata-eh.c.  ata_scsi_timed_out(), ata_scsi_error(),
ata_qc_timeout(), ata_eng_timeout(), ata_eh_qc_complete() and
ata_eh_qc_retry() are moved.  No code is changed by this patch.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 264 insertions, 0 deletions

diff --git a/drivers/scsi/libata-eh.c b/drivers/scsi/libata-eh.c
new file mode 100644
index 000000000000..e73f5612aea8
--- /dev/null
+++ b/drivers/scsi/libata-eh.c
@@ -0,0 +1,264 @@
+/*
+ *  libata-eh.c - libata error handling
+ *
+ *  Maintained by:  Jeff Garzik <jgarzik@pobox.com>
+ *    		    Please ALWAYS copy linux-ide@vger.kernel.org
+ *		    on emails.
+ *
+ *  Copyright 2006 Tejun Heo <htejun@gmail.com>
+ *
+ *
+ *  This program is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU General Public License as
+ *  published by the Free Software Foundation; either version 2, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; see the file COPYING.  If not, write to
+ *  the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139,
+ *  USA.
+ *
+ *
+ *  libata documentation is available via 'make {ps|pdf}docs',
+ *  as Documentation/DocBook/libata.*
+ *
+ *  Hardware documentation available from http://www.t13.org/ and
+ *  http://www.sata-io.org/
+ *
+ */
+
+#include <linux/config.h>
+#include <linux/kernel.h>
+#include <scsi/scsi.h>
+#include <scsi/scsi_host.h>
+#include <scsi/scsi_eh.h>
+#include <scsi/scsi_device.h>
+#include <scsi/scsi_cmnd.h>
+
+#include <linux/libata.h>
+
+#include "libata.h"
+
+/**
+ *	ata_scsi_timed_out - SCSI layer time out callback
+ *	@cmd: timed out SCSI command
+ *
+ *	Handles SCSI layer timeout.  We race with normal completion of
+ *	the qc for @cmd.  If the qc is already gone, we lose and let
+ *	the scsi command finish (EH_HANDLED).  Otherwise, the qc has
+ *	timed out and EH should be invoked.  Prevent ata_qc_complete()
+ *	from finishing it by setting EH_SCHEDULED and return
+ *	EH_NOT_HANDLED.
+ *
+ *	LOCKING:
+ *	Called from timer context
+ *
+ *	RETURNS:
+ *	EH_HANDLED or EH_NOT_HANDLED
+ */
+enum scsi_eh_timer_return ata_scsi_timed_out(struct scsi_cmnd *cmd)
+{
+	struct Scsi_Host *host = cmd->device->host;
+	struct ata_port *ap = (struct ata_port *) &host->hostdata[0];
+	unsigned long flags;
+	struct ata_queued_cmd *qc;
+	enum scsi_eh_timer_return ret = EH_HANDLED;
+
+	DPRINTK("ENTER\n");
+
+	spin_lock_irqsave(&ap->host_set->lock, flags);
+	qc = ata_qc_from_tag(ap, ap->active_tag);
+	if (qc) {
+		WARN_ON(qc->scsicmd != cmd);
+		qc->flags |= ATA_QCFLAG_EH_SCHEDULED;
+		qc->err_mask |= AC_ERR_TIMEOUT;
+		ret = EH_NOT_HANDLED;
+	}
+	spin_unlock_irqrestore(&ap->host_set->lock, flags);
+
+	DPRINTK("EXIT, ret=%d\n", ret);
+	return ret;
+}
+
+/**
+ *	ata_scsi_error - SCSI layer error handler callback
+ *	@host: SCSI host on which error occurred
+ *
+ *	Handles SCSI-layer-thrown error events.
+ *
+ *	LOCKING:
+ *	Inherited from SCSI layer (none, can sleep)
+ *
+ *	RETURNS:
+ *	Zero.
+ */
+int ata_scsi_error(struct Scsi_Host *host)
+{
+	struct ata_port *ap = (struct ata_port *)&host->hostdata[0];
+
+	DPRINTK("ENTER\n");
+
+	/* synchronize with IRQ handler and port task */
+	spin_unlock_wait(&ap->host_set->lock);
+	ata_port_flush_task(ap);
+
+	WARN_ON(ata_qc_from_tag(ap, ap->active_tag) == NULL);
+
+	ap->ops->eng_timeout(ap);
+
+	WARN_ON(host->host_failed || !list_empty(&host->eh_cmd_q));
+
+	scsi_eh_flush_done_q(&ap->eh_done_q);
+
+	DPRINTK("EXIT\n");
+	return 0;
+}
+
+/**
+ *	ata_qc_timeout - Handle timeout of queued command
+ *	@qc: Command that timed out
+ *
+ *	Some part of the kernel (currently, only the SCSI layer)
+ *	has noticed that the active command on port @ap has not
+ *	completed after a specified length of time.  Handle this
+ *	condition by disabling DMA (if necessary) and completing
+ *	transactions, with error if necessary.
+ *
+ *	This also handles the case of the "lost interrupt", where
+ *	for some reason (possibly hardware bug, possibly driver bug)
+ *	an interrupt was not delivered to the driver, even though the
+ *	transaction completed successfully.
+ *
+ *	LOCKING:
+ *	Inherited from SCSI layer (none, can sleep)
+ */
+static void ata_qc_timeout(struct ata_queued_cmd *qc)
+{
+	struct ata_port *ap = qc->ap;
+	struct ata_host_set *host_set = ap->host_set;
+	u8 host_stat = 0, drv_stat;
+	unsigned long flags;
+
+	DPRINTK("ENTER\n");
+
+	ap->hsm_task_state = HSM_ST_IDLE;
+
+	spin_lock_irqsave(&host_set->lock, flags);
+
+	switch (qc->tf.protocol) {
+
+	case ATA_PROT_DMA:
+	case ATA_PROT_ATAPI_DMA:
+		host_stat = ap->ops->bmdma_status(ap);
+
+		/* before we do anything else, clear DMA-Start bit */
+		ap->ops->bmdma_stop(qc);
+
+		/* fall through */
+
+	default:
+		ata_altstatus(ap);
+		drv_stat = ata_chk_status(ap);
+
+		/* ack bmdma irq events */
+		ap->ops->irq_clear(ap);
+
+		printk(KERN_ERR "ata%u: command 0x%x timeout, stat 0x%x host_stat 0x%x\n",
+		       ap->id, qc->tf.command, drv_stat, host_stat);
+
+		/* complete taskfile transaction */
+		qc->err_mask |= ac_err_mask(drv_stat);
+		break;
+	}
+
+	spin_unlock_irqrestore(&host_set->lock, flags);
+
+	ata_eh_qc_complete(qc);
+
+	DPRINTK("EXIT\n");
+}
+
+/**
+ *	ata_eng_timeout - Handle timeout of queued command
+ *	@ap: Port on which timed-out command is active
+ *
+ *	Some part of the kernel (currently, only the SCSI layer)
+ *	has noticed that the active command on port @ap has not
+ *	completed after a specified length of time.  Handle this
+ *	condition by disabling DMA (if necessary) and completing
+ *	transactions, with error if necessary.
+ *
+ *	This also handles the case of the "lost interrupt", where
+ *	for some reason (possibly hardware bug, possibly driver bug)
+ *	an interrupt was not delivered to the driver, even though the
+ *	transaction completed successfully.
+ *
+ *	LOCKING:
+ *	Inherited from SCSI layer (none, can sleep)
+ */
+void ata_eng_timeout(struct ata_port *ap)
+{
+	DPRINTK("ENTER\n");
+
+	ata_qc_timeout(ata_qc_from_tag(ap, ap->active_tag));
+
+	DPRINTK("EXIT\n");
+}
+
+static void ata_eh_scsidone(struct scsi_cmnd *scmd)
+{
+	/* nada */
+}
+
+static void __ata_eh_qc_complete(struct ata_queued_cmd *qc)
+{
+	struct ata_port *ap = qc->ap;
+	struct scsi_cmnd *scmd = qc->scsicmd;
+	unsigned long flags;
+
+	spin_lock_irqsave(&ap->host_set->lock, flags);
+	qc->scsidone = ata_eh_scsidone;
+	__ata_qc_complete(qc);
+	WARN_ON(ata_tag_valid(qc->tag));
+	spin_unlock_irqrestore(&ap->host_set->lock, flags);
+
+	scsi_eh_finish_cmd(scmd, &ap->eh_done_q);
+}
+
+/**
+ *	ata_eh_qc_complete - Complete an active ATA command from EH
+ *	@qc: Command to complete
+ *
+ *	Indicate to the mid and upper layers that an ATA command has
+ *	completed.  To be used from EH.
+ */
+void ata_eh_qc_complete(struct ata_queued_cmd *qc)
+{
+	struct scsi_cmnd *scmd = qc->scsicmd;
+	scmd->retries = scmd->allowed;
+	__ata_eh_qc_complete(qc);
+}
+
+/**
+ *	ata_eh_qc_retry - Tell midlayer to retry an ATA command after EH
+ *	@qc: Command to retry
+ *
+ *	Indicate to the mid and upper layers that an ATA command
+ *	should be retried.  To be used from EH.
+ *
+ *	SCSI midlayer limits the number of retries to scmd->allowed.
+ *	scmd->retries is decremented for commands which get retried
+ *	due to unrelated failures (qc->err_mask is zero).
+ */
+void ata_eh_qc_retry(struct ata_queued_cmd *qc)
+{
+	struct scsi_cmnd *scmd = qc->scsicmd;
+	if (!qc->err_mask && scmd->retries)
+		scmd->retries--;
+	__ata_eh_qc_complete(qc);
+}