Commit 0390f0c0 authored by Stephen M. Cameron's avatar Stephen M. Cameron Committed by James Bottomley
Browse files

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



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: default avatarStephen M. Cameron <scameron@beardog.cce.hp.com>
Signed-off-by: default avatarJames Bottomley <JBottomley@Parallels.com>
parent e06c8e5c

drivers/scsi/hpsa.c

+42 −2
Original line number Diff line number Diff line
@@ -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;

drivers/scsi/hpsa.h

+5 −0
Original line number Diff line number Diff line
@@ -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

	 */

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