Commit ba31f97d authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'for-linus-5.14-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip 

Pull xen fixes from Juergen Gross:
 "A small cleanup patch and a fix of a rare race in the Xen evtchn
  driver"

* tag 'for-linus-5.14-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/events: Fix race in set_evtchn_to_irq
  xen/events: remove redundant initialization of variable irq
parents a7a4f1c0 88ca2521

drivers/xen/events/events_base.c

+15 −7
Original line number Diff line number Diff line
@@ -198,12 +198,12 @@ static void disable_dynirq(struct irq_data *data); 


static DEFINE_PER_CPU(unsigned int, irq_epoch);



static void clear_evtchn_to_irq_row(unsigned row)

static void clear_evtchn_to_irq_row(int *evtchn_row)

{

	unsigned col;



	for (col = 0; col < EVTCHN_PER_ROW; col++)

		WRITE_ONCE(evtchn_to_irq[row][col], -1);

		WRITE_ONCE(evtchn_row[col], -1);

}



static void clear_evtchn_to_irq_all(void)
@@ -213,7 +213,7 @@ static void clear_evtchn_to_irq_all(void) 
	for (row = 0; row < EVTCHN_ROW(xen_evtchn_max_channels()); row++) {

		if (evtchn_to_irq[row] == NULL)

			continue;

		clear_evtchn_to_irq_row(row);

		clear_evtchn_to_irq_row(evtchn_to_irq[row]);

	}

}
@@ -221,6 +221,7 @@ static int set_evtchn_to_irq(evtchn_port_t evtchn, unsigned int irq) 
{

	unsigned row;

	unsigned col;

	int *evtchn_row;



	if (evtchn >= xen_evtchn_max_channels())

		return -EINVAL;
@@ -233,11 +234,18 @@ static int set_evtchn_to_irq(evtchn_port_t evtchn, unsigned int irq) 
		if (irq == -1)

			return 0;



		evtchn_to_irq[row] = (int *)get_zeroed_page(GFP_KERNEL);

		if (evtchn_to_irq[row] == NULL)

		evtchn_row = (int *) __get_free_pages(GFP_KERNEL, 0);

		if (evtchn_row == NULL)

			return -ENOMEM;



		clear_evtchn_to_irq_row(row);

		clear_evtchn_to_irq_row(evtchn_row);



		/*

		 * We've prepared an empty row for the mapping. If a different

		 * thread was faster inserting it, we can drop ours.

		 */

		if (cmpxchg(&evtchn_to_irq[row], NULL, evtchn_row) != NULL)

			free_page((unsigned long) evtchn_row);

	}



	WRITE_ONCE(evtchn_to_irq[row][col], irq);
@@ -1009,7 +1017,7 @@ static void __unbind_from_irq(unsigned int irq) 
int xen_bind_pirq_gsi_to_irq(unsigned gsi,

			     unsigned pirq, int shareable, char *name)

{

	int irq = -1;

	int irq;

	struct physdev_irq irq_op;

	int ret;