[PATCH 0/4] sym53c8xx_2: Fixes for SCSI EH rework

[PATCH 0/4] sym53c8xx_2: Fixes for SCSI EH rework

[Hannes Reinecke]

Hi all,

with the SCSI EH rework the scsi_cmnd argument for the SCSI EH
callbacks is going away, so we need to fixup the drivers to work
without it.

This patchset modifies the sym53c8xx_2 driver to split off the
combined SCSI EH routine into the individual EH callbacks and to
not rely on a specific command for those.

As usual, comments and reviews are welcome.

Hannes Reinecke (4):
  sym53c8xx_2: move PCI EEH handling to host reset
  sym53c8xx_2: split off host reset from sym_eh_handler()
  sym53c8xx_2: split off bus reset from sym_eh_handler()
  sym53c8xx_2: rework reset handling

 drivers/scsi/sym53c8xx_2/sym_glue.c | 220 +++++++++++++++++++---------
 1 file changed, 147 insertions(+), 73 deletions(-)

-- 
2.29.2

[PATCH 1/4] sym53c8xx_2: move PCI EEH handling to host reset

[Hannes Reinecke]

When PCI EEH is active the entire card will be reset; which means
that we _have_ to do the equivalent of a eh_host_reset().
So trying to do it from other EH callbacks is pointless, and we
should delegate it to eh_host_reset().

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/scsi/sym53c8xx_2/sym_glue.c | 97 ++++++++++++++++++-----------
 1 file changed, 60 insertions(+), 37 deletions(-)

diff --git a/drivers/scsi/sym53c8xx_2/sym_glue.c b/drivers/scsi/sym53c8xx_2/sym_glue.c
index 16b65fc4405c..dafdab5869fa 100644
--- a/drivers/scsi/sym53c8xx_2/sym_glue.c
+++ b/drivers/scsi/sym53c8xx_2/sym_glue.c
@@ -569,12 +569,11 @@ static void sym53c8xx_timer(struct timer_list *t)
  *  Generic method for our eh processing.
  *  The 'op' argument tells what we have to do.
  */
-static int sym_eh_handler(int op, char *opname, struct scsi_cmnd *cmd)
+static int sym_eh_handler(struct Scsi_Host *shost, int op,
+			  char *opname, struct scsi_cmnd *cmd)
 {
 	struct sym_ucmd *ucmd = SYM_UCMD_PTR(cmd);
-	struct Scsi_Host *shost = cmd->device->host;
 	struct sym_data *sym_data = shost_priv(shost);
-	struct pci_dev *pdev = sym_data->pdev;
 	struct sym_hcb *np = sym_data->ncb;
 	SYM_QUEHEAD *qp;
 	int cmd_queued = 0;
@@ -583,36 +582,6 @@ static int sym_eh_handler(int op, char *opname, struct scsi_cmnd *cmd)
 
 	scmd_printk(KERN_WARNING, cmd, "%s operation started\n", opname);
 
-	/* We may be in an error condition because the PCI bus
-	 * went down. In this case, we need to wait until the
-	 * PCI bus is reset, the card is reset, and only then
-	 * proceed with the scsi error recovery.  There's no
-	 * point in hurrying; take a leisurely wait.
-	 */
-#define WAIT_FOR_PCI_RECOVERY	35
-	if (pci_channel_offline(pdev)) {
-		int finished_reset = 0;
-		init_completion(&eh_done);
-		spin_lock_irq(shost->host_lock);
-		/* Make sure we didn't race */
-		if (pci_channel_offline(pdev)) {
-			BUG_ON(sym_data->io_reset);
-			sym_data->io_reset = &eh_done;
-		} else {
-			finished_reset = 1;
-		}
-		spin_unlock_irq(shost->host_lock);
-		if (!finished_reset)
-			finished_reset = wait_for_completion_timeout
-						(sym_data->io_reset,
-						WAIT_FOR_PCI_RECOVERY*HZ);
-		spin_lock_irq(shost->host_lock);
-		sym_data->io_reset = NULL;
-		spin_unlock_irq(shost->host_lock);
-		if (!finished_reset)
-			return SCSI_FAILED;
-	}
-
 	spin_lock_irq(shost->host_lock);
 	/* This one is queued in some place -> to wait for completion */
 	FOR_EACH_QUEUED_ELEMENT(&np->busy_ccbq, qp) {
@@ -672,22 +641,76 @@ static int sym_eh_handler(int op, char *opname, struct scsi_cmnd *cmd)
  */
 static int sym53c8xx_eh_abort_handler(struct scsi_cmnd *cmd)
 {
-	return sym_eh_handler(SYM_EH_ABORT, "ABORT", cmd);
+	struct Scsi_Host *shost = cmd->device->host;
+	struct sym_data *sym_data = shost_priv(shost);
+	struct pci_dev *pdev = sym_data->pdev;
+
+	if (pci_channel_offline(pdev))
+		return FAILED;
+	return sym_eh_handler(shost, SYM_EH_ABORT, "ABORT", cmd);
 }
 
 static int sym53c8xx_eh_device_reset_handler(struct scsi_cmnd *cmd)
 {
-	return sym_eh_handler(SYM_EH_DEVICE_RESET, "DEVICE RESET", cmd);
+	struct Scsi_Host *shost = cmd->device->host;
+	struct sym_data *sym_data = shost_priv(shost);
+	struct pci_dev *pdev = sym_data->pdev;
+
+	if (pci_channel_offline(pdev))
+		return FAILED;
+	return sym_eh_handler(shost, SYM_EH_DEVICE_RESET, "DEVICE RESET", cmd);
 }
 
 static int sym53c8xx_eh_bus_reset_handler(struct scsi_cmnd *cmd)
 {
-	return sym_eh_handler(SYM_EH_BUS_RESET, "BUS RESET", cmd);
+	struct Scsi_Host *shost = cmd->device->host;
+	struct sym_data *sym_data = shost_priv(shost);
+	struct pci_dev *pdev = sym_data->pdev;
+
+	if (pci_channel_offline(pdev))
+		return FAILED;
+	return sym_eh_handler(shost, SYM_EH_BUS_RESET, "BUS RESET", cmd);
 }
 
 static int sym53c8xx_eh_host_reset_handler(struct scsi_cmnd *cmd)
 {
-	return sym_eh_handler(SYM_EH_HOST_RESET, "HOST RESET", cmd);
+	struct Scsi_Host *shost = cmd->device->host;
+	struct sym_data *sym_data = shost_priv(shost);
+	struct pci_dev *pdev = sym_data->pdev;
+
+	/* We may be in an error condition because the PCI bus
+	 * went down. In this case, we need to wait until the
+	 * PCI bus is reset, the card is reset, and only then
+	 * proceed with the scsi error recovery.  There's no
+	 * point in hurrying; take a leisurely wait.
+	 */
+#define WAIT_FOR_PCI_RECOVERY	35
+	if (pci_channel_offline(pdev)) {
+		struct completion eh_done;
+		int finished_reset = 0;
+
+		init_completion(&eh_done);
+		spin_lock_irq(shost->host_lock);
+		/* Make sure we didn't race */
+		if (pci_channel_offline(pdev)) {
+			BUG_ON(sym_data->io_reset);
+			sym_data->io_reset = &eh_done;
+		} else {
+			finished_reset = 1;
+		}
+		spin_unlock_irq(shost->host_lock);
+		if (!finished_reset)
+			finished_reset = wait_for_completion_timeout
+						(sym_data->io_reset,
+						WAIT_FOR_PCI_RECOVERY*HZ);
+		spin_lock_irq(shost->host_lock);
+		sym_data->io_reset = NULL;
+		spin_unlock_irq(shost->host_lock);
+		if (!finished_reset)
+			return SCSI_FAILED;
+	}
+
+	return sym_eh_handler(shost, SYM_EH_HOST_RESET, "HOST RESET", cmd);
 }
 
 /*
-- 
2.29.2

Re: [PATCH 1/4] sym53c8xx_2: move PCI EEH handling to host reset

[Christoph Hellwig]

On Thu, Aug 19, 2021 at 11:07:13AM +0200, Hannes Reinecke wrote:
> When PCI EEH is active the entire card will be reset; which means
> that we _have_ to do the equivalent of a eh_host_reset().
> So trying to do it from other EH callbacks is pointless, and we
> should delegate it to eh_host_reset().
> 
> Signed-off-by: Hannes Reinecke <hare@suse.de>

Looks good,

Reviewed-by: Christoph Hellwig <hch@lst.de>

[PATCH 2/4] sym53c8xx_2: split off host reset from sym_eh_handler()

[Hannes Reinecke]

For host reset we need to wait for all pending command to complete;
there might be more than one command queued and we'll need to wait
for all of them.
So split off the host reset functionality from sym_eh_handler()
and add a wait loop for all commands.

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/scsi/sym53c8xx_2/sym_glue.c | 42 ++++++++++++++++++++++++-----
 1 file changed, 35 insertions(+), 7 deletions(-)

diff --git a/drivers/scsi/sym53c8xx_2/sym_glue.c b/drivers/scsi/sym53c8xx_2/sym_glue.c
index dafdab5869fa..86cba915b62d 100644
--- a/drivers/scsi/sym53c8xx_2/sym_glue.c
+++ b/drivers/scsi/sym53c8xx_2/sym_glue.c
@@ -563,7 +563,27 @@ static void sym53c8xx_timer(struct timer_list *t)
 #define SYM_EH_ABORT		0
 #define SYM_EH_DEVICE_RESET	1
 #define SYM_EH_BUS_RESET	2
-#define SYM_EH_HOST_RESET	3
+
+static int sym_eh_wait_for_commands(struct Scsi_Host *shost)
+{
+	struct sym_data *sym_data = shost_priv(shost);
+	struct sym_hcb *np = sym_data->ncb;
+	int rval = SUCCESS, count = 10; /* 5 seconds */
+
+	/* Wait for any queued commands to complete */
+	spin_lock_irq(shost->host_lock);
+	while (!sym_que_empty(&np->busy_ccbq)) {
+		if (--count == 0) {
+			rval = FAILED;
+			break;
+		}
+		spin_unlock_irq(shost->host_lock);
+		msleep(500);
+		spin_lock_irq(shost->host_lock);
+	}
+	spin_unlock_irq(shost->host_lock);
+	return rval;
+}
 
 /*
  *  Generic method for our eh processing.
@@ -605,11 +625,6 @@ static int sym_eh_handler(struct Scsi_Host *shost, int op,
 		sym_reset_scsi_bus(np, 1);
 		sts = 0;
 		break;
-	case SYM_EH_HOST_RESET:
-		sym_reset_scsi_bus(np, 0);
-		sym_start_up(shost, 1);
-		sts = 0;
-		break;
 	default:
 		break;
 	}
@@ -677,6 +692,10 @@ static int sym53c8xx_eh_host_reset_handler(struct scsi_cmnd *cmd)
 	struct Scsi_Host *shost = cmd->device->host;
 	struct sym_data *sym_data = shost_priv(shost);
 	struct pci_dev *pdev = sym_data->pdev;
+	struct sym_hcb *np = sym_data->ncb;
+	int rval = SUCCESS;
+
+	shost_printk(KERN_WARNING, shost, "HOST RESET operation started\n");
 
 	/* We may be in an error condition because the PCI bus
 	 * went down. In this case, we need to wait until the
@@ -710,7 +729,16 @@ static int sym53c8xx_eh_host_reset_handler(struct scsi_cmnd *cmd)
 			return SCSI_FAILED;
 	}
 
-	return sym_eh_handler(shost, SYM_EH_HOST_RESET, "HOST RESET", cmd);
+	spin_lock_irq(shost->host_lock);
+	sym_reset_scsi_bus(np, 0);
+	sym_start_up(shost, 1);
+	spin_unlock_irq(shost->host_lock);
+
+	rval = sym_eh_wait_for_commands(shost);
+
+	shost_printk(KERN_WARNING, shost, "HOST RESET operation %s.\n",
+		     rval == SUCCESS ? "complete" : "failed");
+	return rval;
 }
 
 /*
-- 
2.29.2

[PATCH 3/4] sym53c8xx_2: split off bus reset from sym_eh_handler()

[Hannes Reinecke]

Bus reset is similar to host reset, and we also need to wait for
all commands to complete. So split off bus reset from sym_eh_handler()
and wait for all commands to complete after resetting the SCSI bus.

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/scsi/sym53c8xx_2/sym_glue.c | 23 +++++++++++++++++------
 1 file changed, 17 insertions(+), 6 deletions(-)

diff --git a/drivers/scsi/sym53c8xx_2/sym_glue.c b/drivers/scsi/sym53c8xx_2/sym_glue.c
index 86cba915b62d..817b2584b4aa 100644
--- a/drivers/scsi/sym53c8xx_2/sym_glue.c
+++ b/drivers/scsi/sym53c8xx_2/sym_glue.c
@@ -562,7 +562,6 @@ static void sym53c8xx_timer(struct timer_list *t)
  */
 #define SYM_EH_ABORT		0
 #define SYM_EH_DEVICE_RESET	1
-#define SYM_EH_BUS_RESET	2
 
 static int sym_eh_wait_for_commands(struct Scsi_Host *shost)
 {
@@ -621,10 +620,6 @@ static int sym_eh_handler(struct Scsi_Host *shost, int op,
 	case SYM_EH_DEVICE_RESET:
 		sts = sym_reset_scsi_target(np, cmd->device->id);
 		break;
-	case SYM_EH_BUS_RESET:
-		sym_reset_scsi_bus(np, 1);
-		sts = 0;
-		break;
 	default:
 		break;
 	}
@@ -681,10 +676,26 @@ static int sym53c8xx_eh_bus_reset_handler(struct scsi_cmnd *cmd)
 	struct Scsi_Host *shost = cmd->device->host;
 	struct sym_data *sym_data = shost_priv(shost);
 	struct pci_dev *pdev = sym_data->pdev;
+	struct sym_hcb *np = sym_data->ncb;
+	int rval = SUCCESS;
 
 	if (pci_channel_offline(pdev))
 		return FAILED;
-	return sym_eh_handler(shost, SYM_EH_BUS_RESET, "BUS RESET", cmd);
+
+	shost_printk(KERN_WARNING, shost, "BUS RESET operation started\n");
+
+	spin_lock_irq(shost->host_lock);
+	if (sym_reset_scsi_bus(np, 1))
+		rval = FAILED;
+	spin_unlock_irq(shost->host_lock);
+
+	if (rval == SUCCESS)
+		rval = sym_eh_wait_for_commands(shost);
+
+	shost_printk(KERN_WARNING, shost, "BUS RESET operation %s.\n",
+			rval == SUCCESS ? "complete" : "failed");
+
+	return rval;
 }
 
 static int sym53c8xx_eh_host_reset_handler(struct scsi_cmnd *cmd)
-- 
2.29.2

[PATCH 4/4] sym53c8xx_2: rework reset handling

[Hannes Reinecke]

Split off the combined abort and device reset handling into
distinct functions.
And the current device reset handler really is a target reset,
so rename it.

Signed-off-by: Hannes Reinecke <hare@suse.com>
---
 drivers/scsi/sym53c8xx_2/sym_glue.c | 86 ++++++++++++++++-------------
 1 file changed, 49 insertions(+), 37 deletions(-)

diff --git a/drivers/scsi/sym53c8xx_2/sym_glue.c b/drivers/scsi/sym53c8xx_2/sym_glue.c
index 817b2584b4aa..8773fbdfd559 100644
--- a/drivers/scsi/sym53c8xx_2/sym_glue.c
+++ b/drivers/scsi/sym53c8xx_2/sym_glue.c
@@ -585,13 +585,12 @@ static int sym_eh_wait_for_commands(struct Scsi_Host *shost)
 }
 
 /*
- *  Generic method for our eh processing.
- *  The 'op' argument tells what we have to do.
+ * Error handlers called from the eh thread (one thread per HBA).
  */
-static int sym_eh_handler(struct Scsi_Host *shost, int op,
-			  char *opname, struct scsi_cmnd *cmd)
+static int sym53c8xx_eh_abort_handler(struct scsi_cmnd *cmd)
 {
 	struct sym_ucmd *ucmd = SYM_UCMD_PTR(cmd);
+	struct Scsi_Host *shost = cmd->device->host;
 	struct sym_data *sym_data = shost_priv(shost);
 	struct sym_hcb *np = sym_data->ncb;
 	SYM_QUEHEAD *qp;
@@ -599,7 +598,7 @@ static int sym_eh_handler(struct Scsi_Host *shost, int op,
 	int sts = -1;
 	struct completion eh_done;
 
-	scmd_printk(KERN_WARNING, cmd, "%s operation started\n", opname);
+	scmd_printk(KERN_WARNING, cmd, "ABORT operation started\n");
 
 	spin_lock_irq(shost->host_lock);
 	/* This one is queued in some place -> to wait for completion */
@@ -611,19 +610,7 @@ static int sym_eh_handler(struct Scsi_Host *shost, int op,
 		}
 	}
 
-	/* Try to proceed the operation we have been asked for */
-	sts = -1;
-	switch(op) {
-	case SYM_EH_ABORT:
-		sts = sym_abort_scsiio(np, cmd, 1);
-		break;
-	case SYM_EH_DEVICE_RESET:
-		sts = sym_reset_scsi_target(np, cmd->device->id);
-		break;
-	default:
-		break;
-	}
-
+	sts = sym_abort_scsiio(np, cmd, 1);
 	/* On error, restore everything and cross fingers :) */
 	if (sts)
 		cmd_queued = 0;
@@ -640,35 +627,60 @@ static int sym_eh_handler(struct Scsi_Host *shost, int op,
 		spin_unlock_irq(shost->host_lock);
 	}
 
-	dev_warn(&cmd->device->sdev_gendev, "%s operation %s.\n", opname,
+	dev_warn(&cmd->device->sdev_gendev, "ABORT operation %s.\n",
 			sts==0 ? "complete" :sts==-2 ? "timed-out" : "failed");
 	return sts ? SCSI_FAILED : SCSI_SUCCESS;
 }
 
-
-/*
- * Error handlers called from the eh thread (one thread per HBA).
- */
-static int sym53c8xx_eh_abort_handler(struct scsi_cmnd *cmd)
+static int sym53c8xx_eh_target_reset_handler(struct scsi_cmnd *cmd)
 {
-	struct Scsi_Host *shost = cmd->device->host;
+	struct scsi_target *starget = scsi_target(cmd->device);
+	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
 	struct sym_data *sym_data = shost_priv(shost);
 	struct pci_dev *pdev = sym_data->pdev;
+	struct sym_hcb *np = sym_data->ncb;
+	SYM_QUEHEAD *qp;
+	int sts;
+	struct completion eh_done;
 
+	starget_printk(KERN_WARNING, starget,
+		       "TARGET RESET operation started\n");
+
+	/*
+	 * Escalate to host reset if the PCI bus went down
+	 */
 	if (pci_channel_offline(pdev))
-		return FAILED;
-	return sym_eh_handler(shost, SYM_EH_ABORT, "ABORT", cmd);
-}
+		return SCSI_FAILED;
 
-static int sym53c8xx_eh_device_reset_handler(struct scsi_cmnd *cmd)
-{
-	struct Scsi_Host *shost = cmd->device->host;
-	struct sym_data *sym_data = shost_priv(shost);
-	struct pci_dev *pdev = sym_data->pdev;
+	spin_lock_irq(shost->host_lock);
+	sts = sym_reset_scsi_target(np, starget->id);
+	if (!sts) {
+		FOR_EACH_QUEUED_ELEMENT(&np->busy_ccbq, qp) {
+			struct sym_ccb *cp = sym_que_entry(qp, struct sym_ccb,
+							   link_ccbq);
+			struct scsi_cmnd *cmd = cp->cmd;
+			struct sym_ucmd *ucmd;
+
+			if (!cmd || cmd->device->channel != starget->channel ||
+			    cmd->device->id != starget->id)
+				continue;
 
-	if (pci_channel_offline(pdev))
-		return FAILED;
-	return sym_eh_handler(shost, SYM_EH_DEVICE_RESET, "DEVICE RESET", cmd);
+			ucmd = SYM_UCMD_PTR(cmd);
+			init_completion(&eh_done);
+			ucmd->eh_done = &eh_done;
+			spin_unlock_irq(shost->host_lock);
+			if (!wait_for_completion_timeout(&eh_done, 5*HZ)) {
+				ucmd->eh_done = NULL;
+				sts = -2;
+			}
+			spin_lock_irq(shost->host_lock);
+		}
+	}
+	spin_unlock_irq(shost->host_lock);
+
+	starget_printk(KERN_WARNING, starget, "TARGET RESET operation %s.\n",
+			sts==0 ? "complete" :sts==-2 ? "timed-out" : "failed");
+	return SCSI_SUCCESS;
 }
 
 static int sym53c8xx_eh_bus_reset_handler(struct scsi_cmnd *cmd)
@@ -1699,7 +1711,7 @@ static struct scsi_host_template sym2_template = {
 	.slave_configure	= sym53c8xx_slave_configure,
 	.slave_destroy		= sym53c8xx_slave_destroy,
 	.eh_abort_handler	= sym53c8xx_eh_abort_handler,
-	.eh_device_reset_handler = sym53c8xx_eh_device_reset_handler,
+	.eh_target_reset_handler = sym53c8xx_eh_target_reset_handler,
 	.eh_bus_reset_handler	= sym53c8xx_eh_bus_reset_handler,
 	.eh_host_reset_handler	= sym53c8xx_eh_host_reset_handler,
 	.this_id		= 7,
-- 
2.29.2