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r: 13944
b: refs/heads/master
c: 3da8b71
h: refs/heads/master
v: v3
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mike.miller@hp.com authored and James Bottomley committed Nov 6, 2005
1 parent 7930202 commit 48cce94
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2 changes: 1 addition & 1 deletion [refs]
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@@ -1,2 +1,2 @@
---
refs/heads/master: 13bf50d1f21b2f11452c4b8a82a91319791f8ba3
refs/heads/master: 3da8b713da723e78a03f0404beedf3cc6f4f860b
29 changes: 29 additions & 0 deletions trunk/Documentation/cciss.txt
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Expand Up @@ -133,3 +133,32 @@ hardware and it is important to prevent the kernel from attempting to directly
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.

188 changes: 162 additions & 26 deletions trunk/drivers/block/cciss.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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,
Expand Down Expand Up @@ -1586,6 +1587,24 @@ static int fill_cmd(CommandList_struct *c, __u8 cmd, int ctlr, void *buff,
}
} 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;
Expand Down Expand Up @@ -1872,6 +1891,52 @@ static unsigned long pollcomplete(int ctlr)
/* 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.
Expand All @@ -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");
Expand All @@ -1916,7 +1981,9 @@ static int sendcmd(
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 */
Expand All @@ -1933,13 +2000,25 @@ static int sendcmd(
* 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)
{
Expand Down Expand Up @@ -1979,6 +2058,10 @@ static int sendcmd(
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,
Expand All @@ -1993,27 +2076,27 @@ static int sendcmd(
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 */
buff_dma_handle.val32.lower = c->SG[0].Addr.lower;
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);
}
Expand Down Expand Up @@ -2338,6 +2421,48 @@ static void do_cciss_request(request_queue_t *q)
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;
Expand All @@ -2347,19 +2472,15 @@ static irqreturn_t do_cciss_intr(int irq, void *dev_id, struct pt_regs *regs)
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);
Expand Down Expand Up @@ -2966,7 +3087,15 @@ static int __devinit cciss_init_one(struct pci_dev *pdev,
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.
Expand Down Expand Up @@ -3034,6 +3163,10 @@ static int __devinit cciss_init_one(struct pci_dev *pdev,
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)
Expand Down Expand Up @@ -3107,6 +3240,9 @@ static void __devexit cciss_remove_one (struct pci_dev *pdev)
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);
}
Expand Down
11 changes: 11 additions & 0 deletions trunk/drivers/block/cciss.h
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Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand Down Expand Up @@ -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;
};
Expand Down
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