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Subject[PATCH 1/1] cciss: scsi error handling
PATCH 1 of 1

This patch adds SCSI error handling code to the SCSI portion
of the cciss driver.

Signed-off-by: Stephen M. Cameron <steve.cameron@hp.com>
Acked-by: Mike Miller <mike.miller@hp.com>


Documentation/cciss.txt | 29 ++++++
drivers/block/cciss.c | 188 ++++++++++++++++++++++++++++++++++++++-------
drivers/block/cciss.h | 11 ++
drivers/block/cciss_scsi.c | 82 +++++++++++++++++++
4 files changed, 283 insertions(+), 27 deletions(-)
--- linux-2.6.14/Documentation/cciss.txt~cciss_scsi_error 2005-10-28 12:19:08.959011488 -0500
+++ linux-2.6.14-scameron/Documentation/cciss.txt 2005-10-28 12:19:08.971009664 -0500
@@ -133,3 +133,32 @@ hardware and it is important to prevent
access these devices too, as if the array controller were merely a SCSI
controller in the same way that we are allowing it to access SCSI tape drives.

+SCSI error handling for tape drives and medium changers
+-------------------------------------------------------
+
+The linux SCSI mid layer provides an error handling protocol which
+kicks into gear whenever a SCSI command fails to complete within a
+certain amount of time (which can vary depending on the command).
+The cciss driver participates in this protocol to some extent. The
+normal protocol is a four step process. First the device is told
+to abort the command. If that doesn't work, the device is reset.
+If that doesn't work, the SCSI bus is reset. If that doesn't work
+the host bus adapter is reset. Because the cciss driver is a block
+driver as well as a SCSI driver and only the tape drives and medium
+changers are presented to the SCSI mid layer, and unlike more
+straightforward SCSI drivers, disk i/o continues through the block
+side during the SCSI error recovery process, the cciss driver only
+implements the first two of these actions, aborting the command, and
+resetting the device. Additionally, most tape drives will not oblige
+in aborting commands, and sometimes it appears they will not even
+obey a reset coommand, though in most circumstances they will. In
+the case that the command cannot be aborted and the device cannot be
+reset, the device will be set offline.
+
+In the event the error handling code is triggered and a tape drive is
+successfully reset or the tardy command is successfully aborted, the
+tape drive may still not allow i/o to continue until some command
+is issued which positions the tape to a known position. Typically you
+must rewind the tape (by issuing "mt -f /dev/st0 rewind" for example)
+before i/o can proceed again to a tape drive which was reset.
+
--- linux-2.6.14/drivers/block/cciss.c~cciss_scsi_error 2005-10-28 12:19:08.964010728 -0500
+++ linux-2.6.14-scameron/drivers/block/cciss.c 2005-10-28 12:21:49.010679936 -0500
@@ -148,6 +148,7 @@ static struct board_type products[] = {
static ctlr_info_t *hba[MAX_CTLR];

static void do_cciss_request(request_queue_t *q);
+static irqreturn_t do_cciss_intr(int irq, void *dev_id, struct pt_regs *regs);
static int cciss_open(struct inode *inode, struct file *filep);
static int cciss_release(struct inode *inode, struct file *filep);
static int cciss_ioctl(struct inode *inode, struct file *filep,
@@ -1586,6 +1587,24 @@ static int fill_cmd(CommandList_struct *
}
} else if (cmd_type == TYPE_MSG) {
switch (cmd) {
+ case 0: /* ABORT message */
+ c->Request.CDBLen = 12;
+ c->Request.Type.Attribute = ATTR_SIMPLE;
+ c->Request.Type.Direction = XFER_WRITE;
+ c->Request.Timeout = 0;
+ c->Request.CDB[0] = cmd; /* abort */
+ c->Request.CDB[1] = 0; /* abort a command */
+ /* buff contains the tag of the command to abort */
+ memcpy(&c->Request.CDB[4], buff, 8);
+ break;
+ case 1: /* RESET message */
+ c->Request.CDBLen = 12;
+ c->Request.Type.Attribute = ATTR_SIMPLE;
+ c->Request.Type.Direction = XFER_WRITE;
+ c->Request.Timeout = 0;
+ memset(&c->Request.CDB[0], 0, sizeof(c->Request.CDB));
+ c->Request.CDB[0] = cmd; /* reset */
+ c->Request.CDB[1] = 0x04; /* reset a LUN */
case 3: /* No-Op message */
c->Request.CDBLen = 1;
c->Request.Type.Attribute = ATTR_SIMPLE;
@@ -1872,6 +1891,52 @@ static unsigned long pollcomplete(int ct
/* Invalid address to tell caller we ran out of time */
return 1;
}
+
+static int add_sendcmd_reject(__u8 cmd, int ctlr, unsigned long complete)
+{
+ /* We get in here if sendcmd() is polling for completions
+ and gets some command back that it wasn't expecting --
+ something other than that which it just sent down.
+ Ordinarily, that shouldn't happen, but it can happen when
+ the scsi tape stuff gets into error handling mode, and
+ starts using sendcmd() to try to abort commands and
+ reset tape drives. In that case, sendcmd may pick up
+ completions of commands that were sent to logical drives
+ through the block i/o system, or cciss ioctls completing, etc.
+ In that case, we need to save those completions for later
+ processing by the interrupt handler.
+ */
+
+#ifdef CONFIG_CISS_SCSI_TAPE
+ struct sendcmd_reject_list *srl = &hba[ctlr]->scsi_rejects;
+
+ /* If it's not the scsi tape stuff doing error handling, (abort */
+ /* or reset) then we don't expect anything weird. */
+ if (cmd != CCISS_RESET_MSG && cmd != CCISS_ABORT_MSG) {
+#endif
+ printk( KERN_WARNING "cciss cciss%d: SendCmd "
+ "Invalid command list address returned! (%lx)\n",
+ ctlr, complete);
+ /* not much we can do. */
+#ifdef CONFIG_CISS_SCSI_TAPE
+ return 1;
+ }
+
+ /* We've sent down an abort or reset, but something else
+ has completed */
+ if (srl->ncompletions >= (NR_CMDS + 2)) {
+ /* Uh oh. No room to save it for later... */
+ printk(KERN_WARNING "cciss%d: Sendcmd: Invalid command addr, "
+ "reject list overflow, command lost!\n", ctlr);
+ return 1;
+ }
+ /* Save it for later */
+ srl->complete[srl->ncompletions] = complete;
+ srl->ncompletions++;
+#endif
+ return 0;
+}
+
/*
* Send a command to the controller, and wait for it to complete.
* Only used at init time.
@@ -1894,7 +1959,7 @@ static int sendcmd(
unsigned long complete;
ctlr_info_t *info_p= hba[ctlr];
u64bit buff_dma_handle;
- int status;
+ int status, done = 0;

if ((c = cmd_alloc(info_p, 1)) == NULL) {
printk(KERN_WARNING "cciss: unable to get memory");
@@ -1916,7 +1981,9 @@ resend_cmd1:
info_p->access.set_intr_mask(info_p, CCISS_INTR_OFF);

/* Make sure there is room in the command FIFO */
- /* Actually it should be completely empty at this time. */
+ /* Actually it should be completely empty at this time */
+ /* unless we are in here doing error handling for the scsi */
+ /* tape side of the driver. */
for (i = 200000; i > 0; i--)
{
/* if fifo isn't full go */
@@ -1933,13 +2000,25 @@ resend_cmd1:
* Send the cmd
*/
info_p->access.submit_command(info_p, c);
- complete = pollcomplete(ctlr);
+ done = 0;
+ do {
+ complete = pollcomplete(ctlr);

#ifdef CCISS_DEBUG
- printk(KERN_DEBUG "cciss: command completed\n");
+ printk(KERN_DEBUG "cciss: command completed\n");
#endif /* CCISS_DEBUG */

- if (complete != 1) {
+ if (complete == 1) {
+ printk( KERN_WARNING
+ "cciss cciss%d: SendCmd Timeout out, "
+ "No command list address returned!\n",
+ ctlr);
+ status = IO_ERROR;
+ done = 1;
+ break;
+ }
+
+ /* This will need to change for direct lookup completions */
if ( (complete & CISS_ERROR_BIT)
&& (complete & ~CISS_ERROR_BIT) == c->busaddr)
{
@@ -1979,6 +2058,10 @@ resend_cmd1:
status = IO_ERROR;
goto cleanup1;
}
+ } else if (c->err_info->CommandStatus == CMD_UNABORTABLE) {
+ printk(KERN_WARNING "cciss%d: command could not be aborted.\n", ctlr);
+ status = IO_ERROR;
+ goto cleanup1;
}
printk(KERN_WARNING "ciss ciss%d: sendcmd"
" Error %x \n", ctlr,
@@ -1993,20 +2076,15 @@ resend_cmd1:
goto cleanup1;
}
}
+ /* This will need changing for direct lookup completions */
if (complete != c->busaddr) {
- printk( KERN_WARNING "cciss cciss%d: SendCmd "
- "Invalid command list address returned! (%lx)\n",
- ctlr, complete);
- status = IO_ERROR;
- goto cleanup1;
- }
- } else {
- printk( KERN_WARNING
- "cciss cciss%d: SendCmd Timeout out, "
- "No command list address returned!\n",
- ctlr);
- status = IO_ERROR;
- }
+ if (add_sendcmd_reject(cmd, ctlr, complete) != 0) {
+ BUG(); /* we are pretty much hosed if we get here. */
+ }
+ continue;
+ } else
+ done = 1;
+ } while (!done);

cleanup1:
/* unlock the data buffer from DMA */
@@ -2014,6 +2092,11 @@ cleanup1:
buff_dma_handle.val32.upper = c->SG[0].Addr.upper;
pci_unmap_single(info_p->pdev, (dma_addr_t) buff_dma_handle.val,
c->SG[0].Len, PCI_DMA_BIDIRECTIONAL);
+#ifdef CONFIG_CISS_SCSI_TAPE
+ /* if we saved some commands for later, process them now. */
+ if (info_p->scsi_rejects.ncompletions > 0)
+ do_cciss_intr(0, info_p, NULL);
+#endif
cmd_free(info_p, c, 1);
return (status);
}
@@ -2338,6 +2421,48 @@ startio:
start_io(h);
}

+static inline unsigned long get_next_completion(ctlr_info_t *h)
+{
+#ifdef CONFIG_CISS_SCSI_TAPE
+ /* Any rejects from sendcmd() lying around? Process them first */
+ if (h->scsi_rejects.ncompletions == 0)
+ return h->access.command_completed(h);
+ else {
+ struct sendcmd_reject_list *srl;
+ int n;
+ srl = &h->scsi_rejects;
+ n = --srl->ncompletions;
+ /* printk("cciss%d: processing saved reject\n", h->ctlr); */
+ printk("p");
+ return srl->complete[n];
+ }
+#else
+ return h->access.command_completed(h);
+#endif
+}
+
+static inline int interrupt_pending(ctlr_info_t *h)
+{
+#ifdef CONFIG_CISS_SCSI_TAPE
+ return ( h->access.intr_pending(h)
+ || (h->scsi_rejects.ncompletions > 0));
+#else
+ return h->access.intr_pending(h);
+#endif
+}
+
+static inline long interrupt_not_for_us(ctlr_info_t *h)
+{
+#ifdef CONFIG_CISS_SCSI_TAPE
+ return (((h->access.intr_pending(h) == 0) ||
+ (h->interrupts_enabled == 0))
+ && (h->scsi_rejects.ncompletions == 0));
+#else
+ return (((h->access.intr_pending(h) == 0) ||
+ (h->interrupts_enabled == 0)));
+#endif
+}
+
static irqreturn_t do_cciss_intr(int irq, void *dev_id, struct pt_regs *regs)
{
ctlr_info_t *h = dev_id;
@@ -2347,19 +2472,15 @@ static irqreturn_t do_cciss_intr(int irq
int j;
int start_queue = h->next_to_run;

- /* Is this interrupt for us? */
- if (( h->access.intr_pending(h) == 0) || (h->interrupts_enabled == 0))
+ if (interrupt_not_for_us(h))
return IRQ_NONE;
-
/*
* If there are completed commands in the completion queue,
* we had better do something about it.
*/
spin_lock_irqsave(CCISS_LOCK(h->ctlr), flags);
- while( h->access.intr_pending(h))
- {
- while((a = h->access.command_completed(h)) != FIFO_EMPTY)
- {
+ while (interrupt_pending(h)) {
+ while((a = get_next_completion(h)) != FIFO_EMPTY) {
a1 = a;
if ((a & 0x04)) {
a2 = (a >> 3);
@@ -2966,7 +3087,15 @@ static int __devinit cciss_init_one(stru
printk( KERN_ERR "cciss: out of memory");
goto clean4;
}
-
+#ifdef CONFIG_CISS_SCSI_TAPE
+ hba[i]->scsi_rejects.complete =
+ kmalloc(sizeof(hba[i]->scsi_rejects.complete[0]) *
+ (NR_CMDS + 5), GFP_KERNEL);
+ if (hba[i]->scsi_rejects.complete == NULL) {
+ printk( KERN_ERR "cciss: out of memory");
+ goto clean4;
+ }
+#endif
spin_lock_init(&hba[i]->lock);

/* Initialize the pdev driver private data.
@@ -3034,6 +3163,10 @@ static int __devinit cciss_init_one(stru
return(1);

clean4:
+#ifdef CONFIG_CISS_SCSI_TAPE
+ if(hba[i]->scsi_rejects.complete)
+ kfree(hba[i]->scsi_rejects.complete);
+#endif
if(hba[i]->cmd_pool_bits)
kfree(hba[i]->cmd_pool_bits);
if(hba[i]->cmd_pool)
@@ -3107,6 +3240,9 @@ static void __devexit cciss_remove_one (
pci_free_consistent(hba[i]->pdev, NR_CMDS * sizeof( ErrorInfo_struct),
hba[i]->errinfo_pool, hba[i]->errinfo_pool_dhandle);
kfree(hba[i]->cmd_pool_bits);
+#ifdef CONFIG_CISS_SCSI_TAPE
+ kfree(hba[i]->scsi_rejects.complete);
+#endif
release_io_mem(hba[i]);
free_hba(i);
}
--- linux-2.6.14/drivers/block/cciss.h~cciss_scsi_error 2005-10-28 12:19:08.966010424 -0500
+++ linux-2.6.14-scameron/drivers/block/cciss.h 2005-10-28 12:19:08.985007536 -0500
@@ -44,6 +44,14 @@ typedef struct _drive_info_struct
*/
} drive_info_struct;

+#ifdef CONFIG_CISS_SCSI_TAPE
+
+struct sendcmd_reject_list {
+ int ncompletions;
+ unsigned long *complete; /* array of NR_CMDS tags */
+};
+
+#endif
struct ctlr_info
{
int ctlr;
@@ -100,6 +108,9 @@ struct ctlr_info
struct gendisk *gendisk[NWD];
#ifdef CONFIG_CISS_SCSI_TAPE
void *scsi_ctlr; /* ptr to structure containing scsi related stuff */
+ /* list of block side commands the scsi error handling sucked up */
+ /* and saved for later processing */
+ struct sendcmd_reject_list scsi_rejects;
#endif
unsigned char alive;
};
--- linux-2.6.14/drivers/block/cciss_scsi.c~cciss_scsi_error 2005-10-28 12:19:08.968010120 -0500
+++ linux-2.6.14-scameron/drivers/block/cciss_scsi.c 2005-10-28 12:19:08.987007232 -0500
@@ -38,6 +38,9 @@

#include "cciss_scsi.h"

+#define CCISS_ABORT_MSG 0x00
+#define CCISS_RESET_MSG 0x01
+
/* some prototypes... */
static int sendcmd(
__u8 cmd,
@@ -63,6 +66,8 @@ static int cciss_scsi_proc_info(

static int cciss_scsi_queue_command (struct scsi_cmnd *cmd,
void (* done)(struct scsi_cmnd *));
+static int cciss_eh_device_reset_handler(struct scsi_cmnd *);
+static int cciss_eh_abort_handler(struct scsi_cmnd *);

static struct cciss_scsi_hba_t ccissscsi[MAX_CTLR] = {
{ .name = "cciss0", .ndevices = 0 },
@@ -86,6 +91,9 @@ static struct scsi_host_template cciss_d
.sg_tablesize = MAXSGENTRIES,
.cmd_per_lun = 1,
.use_clustering = DISABLE_CLUSTERING,
+ /* Can't have eh_bus_reset_handler or eh_host_reset_handler for cciss */
+ .eh_device_reset_handler= cciss_eh_device_reset_handler,
+ .eh_abort_handler = cciss_eh_abort_handler,
};

#pragma pack(1)
@@ -243,7 +251,7 @@ scsi_cmd_stack_free(int ctlr)
#define DEVICETYPE(n) (n<0 || n>MAX_SCSI_DEVICE_CODE) ? \
"Unknown" : scsi_device_types[n]

-#if 0
+#if 1
static int xmargin=8;
static int amargin=60;

@@ -1444,6 +1452,78 @@ cciss_proc_tape_report(int ctlr, unsigne
*pos += size; *len += size;
}

+/* Need at least one of these error handlers to keep ../scsi/hosts.c from
+ * complaining. Doing a host- or bus-reset can't do anything good here.
+ * Despite what it might say in scsi_error.c, there may well be commands
+ * on the controller, as the cciss driver registers twice, once as a block
+ * device for the logical drives, and once as a scsi device, for any tape
+ * drives. So we know there are no commands out on the tape drives, but we
+ * don't know there are no commands on the controller, and it is likely
+ * that there probably are, as the cciss block device is most commonly used
+ * as a boot device (embedded controller on HP/Compaq systems.)
+*/
+
+static int cciss_eh_device_reset_handler(struct scsi_cmnd *scsicmd)
+{
+ int rc;
+ CommandList_struct *cmd_in_trouble;
+ ctlr_info_t **c;
+ int ctlr;
+
+ /* find the controller to which the command to be aborted was sent */
+ c = (ctlr_info_t **) &scsicmd->device->host->hostdata[0];
+ if (c == NULL) /* paranoia */
+ return FAILED;
+ ctlr = (*c)->ctlr;
+ printk(KERN_WARNING "cciss%d: resetting tape drive or medium changer.\n", ctlr);
+
+ /* find the command that's giving us trouble */
+ cmd_in_trouble = (CommandList_struct *) scsicmd->host_scribble;
+ if (cmd_in_trouble == NULL) { /* paranoia */
+ return FAILED;
+ }
+ /* send a reset to the SCSI LUN which the command was sent to */
+ rc = sendcmd(CCISS_RESET_MSG, ctlr, NULL, 0, 2, 0, 0,
+ (unsigned char *) &cmd_in_trouble->Header.LUN.LunAddrBytes[0],
+ TYPE_MSG);
+ /* sendcmd turned off interrputs on the board, turn 'em back on. */
+ (*c)->access.set_intr_mask(*c, CCISS_INTR_ON);
+ if (rc == 0)
+ return SUCCESS;
+ printk(KERN_WARNING "cciss%d: resetting device failed.\n", ctlr);
+ return FAILED;
+}
+
+static int cciss_eh_abort_handler(struct scsi_cmnd *scsicmd)
+{
+ int rc;
+ CommandList_struct *cmd_to_abort;
+ ctlr_info_t **c;
+ int ctlr;
+
+ /* find the controller to which the command to be aborted was sent */
+ c = (ctlr_info_t **) &scsicmd->device->host->hostdata[0];
+ if (c == NULL) /* paranoia */
+ return FAILED;
+ ctlr = (*c)->ctlr;
+ printk(KERN_WARNING "cciss%d: aborting tardy SCSI cmd\n", ctlr);
+
+ /* find the command to be aborted */
+ cmd_to_abort = (CommandList_struct *) scsicmd->host_scribble;
+ if (cmd_to_abort == NULL) /* paranoia */
+ return FAILED;
+ rc = sendcmd(CCISS_ABORT_MSG, ctlr, &cmd_to_abort->Header.Tag,
+ 0, 2, 0, 0,
+ (unsigned char *) &cmd_to_abort->Header.LUN.LunAddrBytes[0],
+ TYPE_MSG);
+ /* sendcmd turned off interrputs on the board, turn 'em back on. */
+ (*c)->access.set_intr_mask(*c, CCISS_INTR_ON);
+ if (rc == 0)
+ return SUCCESS;
+ return FAILED;
+
+}
+
#else /* no CONFIG_CISS_SCSI_TAPE */

/* If no tape support, then these become defined out of existence */
_
-
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