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[SCSI] hpsa: cap CCISS_PASSTHRU at 20 concurrent commands.

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Cap CCISS_BIG_PASSTHRU as well.  If an attempt is made
to exceed this, ioctl() will return -1 with errno == EAGAIN.

This is to prevent a userland program from exhausting all of
pci_alloc_consistent memory.  I've only seen this problem when
running a special test program designed to provoke it.  20
concurrent commands via the passthru ioctls (not counting SG_IO)
should be more than enough.

Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
This commit is contained in:
Stephen M. Cameron 2013-09-23 13:34:12 -05:00 committed by James Bottomley
parent e06c8e5c34
commit 0390f0c0df
2 changed files with 47 additions and 2 deletions
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44
drivers/scsi/hpsa.c
View File

@ -3222,6 +3222,36 @@ static void check_ioctl_unit_attention(struct ctlr_info *h,
c->err_info->ScsiStatus != SAM_STAT_CHECK_CONDITION)
(void) check_for_unit_attention(h, c);
}
static int increment_passthru_count(struct ctlr_info *h)
{
unsigned long flags;
spin_lock_irqsave(&h->passthru_count_lock, flags);
if (h->passthru_count >= HPSA_MAX_CONCURRENT_PASSTHRUS) {
spin_unlock_irqrestore(&h->passthru_count_lock, flags);
return -1;
}
h->passthru_count++;
spin_unlock_irqrestore(&h->passthru_count_lock, flags);
return 0;
}
static void decrement_passthru_count(struct ctlr_info *h)
{
unsigned long flags;
spin_lock_irqsave(&h->passthru_count_lock, flags);
if (h->passthru_count <= 0) {
spin_unlock_irqrestore(&h->passthru_count_lock, flags);
/* not expecting to get here. */
dev_warn(&h->pdev->dev, "Bug detected, passthru_count seems to be incorrect.\n");
return;
}
h->passthru_count--;
spin_unlock_irqrestore(&h->passthru_count_lock, flags);
}
/*
* ioctl
*/
@ -3229,6 +3259,7 @@ static int hpsa_ioctl(struct scsi_device *dev, int cmd, void *arg)
{
struct ctlr_info *h;
void __user *argp = (void __user *)arg;
int rc;
h = sdev_to_hba(dev);
@ -3243,9 +3274,17 @@ static int hpsa_ioctl(struct scsi_device *dev, int cmd, void *arg)
case CCISS_GETDRIVVER:
return hpsa_getdrivver_ioctl(h, argp);
case CCISS_PASSTHRU:
return hpsa_passthru_ioctl(h, argp);
if (increment_passthru_count(h))
return -EAGAIN;
rc = hpsa_passthru_ioctl(h, argp);
decrement_passthru_count(h);
return rc;
case CCISS_BIG_PASSTHRU:
return hpsa_big_passthru_ioctl(h, argp);
if (increment_passthru_count(h))
return -EAGAIN;
rc = hpsa_big_passthru_ioctl(h, argp);
decrement_passthru_count(h);
return rc;
default:
return -ENOTTY;
}
@ -4835,6 +4874,7 @@ reinit_after_soft_reset:
INIT_LIST_HEAD(&h->reqQ);
spin_lock_init(&h->lock);
spin_lock_init(&h->scan_lock);
spin_lock_init(&h->passthru_count_lock);
rc = hpsa_pci_init(h);
if (rc != 0)
goto clean1;

5
drivers/scsi/hpsa.h
View File

@ -114,6 +114,11 @@ struct ctlr_info {
struct TransTable_struct *transtable;
unsigned long transMethod;
/* cap concurrent passthrus at some reasonable maximum */
#define HPSA_MAX_CONCURRENT_PASSTHRUS (20)
spinlock_t passthru_count_lock; /* protects passthru_count */
int passthru_count;
/*
* Performant mode completion buffers
*/