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Commit b6c96c02 authored by Stratos Psomadakis's avatar Stratos Psomadakis Committed by Rusty Russell
Browse files

lguest: Make sure interrupt is allocated ok by lguest_setup_irq 



Make sure the interrupt is allocated correctly by lguest_setup_irq (check the
return value of irq_alloc_desc_at for -ENOMEM)

Signed-off-by: default avatarStratos Psomadakis <psomas@cslab.ece.ntua.gr>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (cleanups and commentry)
parent 07fe9977

arch/x86/lguest/boot.c

+13 −8
Original line number Diff line number Diff line
@@ -856,18 +856,23 @@ static void __init lguest_init_IRQ(void) 
}



/*

 * With CONFIG_SPARSE_IRQ, interrupt descriptors are allocated as-needed, so

 * rather than set them in lguest_init_IRQ we are called here every time an

 * lguest device needs an interrupt.

 *

 * FIXME: irq_alloc_desc_at() can fail due to lack of memory, we should

 * pass that up!

 * Interrupt descriptors are allocated as-needed, but low-numbered ones are

 * reserved by the generic x86 code.  So we ignore irq_alloc_desc_at if it

 * tells us the irq is already used: other errors (ie. ENOMEM) we take

 * seriously.

 */

void lguest_setup_irq(unsigned int irq)

int lguest_setup_irq(unsigned int irq)

{

	irq_alloc_desc_at(irq, 0);

	int err;



	/* Returns -ve error or vector number. */

	err = irq_alloc_desc_at(irq, 0);

	if (err < 0 && err != -EEXIST)

		return err;



	irq_set_chip_and_handler_name(irq, &lguest_irq_controller,

				      handle_level_irq, "level");

	return 0;

}



/*

drivers/lguest/lguest_device.c

+7 −3
Original line number Diff line number Diff line
@@ -241,7 +241,7 @@ static void lg_notify(struct virtqueue *vq) 
}



/* An extern declaration inside a C file is bad form.  Don't do it. */

extern void lguest_setup_irq(unsigned int irq);

extern int lguest_setup_irq(unsigned int irq);



/*

 * This routine finds the Nth virtqueue described in the configuration of
@@ -304,7 +304,9 @@ static struct virtqueue *lg_find_vq(struct virtio_device *vdev, 
	}



	/* Make sure the interrupt is allocated. */

	lguest_setup_irq(lvq->config.irq);

	err = lguest_setup_irq(lvq->config.irq);

	if (err)

		goto destroy_vring;



	/*

	 * Tell the interrupt for this virtqueue to go to the virtio_ring
@@ -317,7 +319,7 @@ static struct virtqueue *lg_find_vq(struct virtio_device *vdev, 
	err = request_irq(lvq->config.irq, vring_interrupt, IRQF_SHARED,

			  dev_name(&vdev->dev), vq);

	if (err)

		goto destroy_vring;

		goto free_desc;



	/*

	 * Last of all we hook up our 'struct lguest_vq_info" to the
@@ -326,6 +328,8 @@ static struct virtqueue *lg_find_vq(struct virtio_device *vdev, 
	vq->priv = lvq;

	return vq;



free_desc:

	irq_free_desc(lvq->config.irq);

destroy_vring:

	vring_del_virtqueue(vq);

unmap: