Commit 5ef3720d authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'powerpc-6.7-5' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux 

Pull powerpc fixes from Michael Ellerman:

 - Fix a bug where heavy VAS (accelerator) usage could race with
   partition migration and prevent the migration from completing.

 - Update MAINTAINERS to add Aneesh & Naveen.

Thanks to Haren Myneni.

* tag 'powerpc-6.7-5' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  MAINTAINERS: powerpc: Add Aneesh & Naveen
  powerpc/pseries/vas: Migration suspend waits for no in-progress open windows
parents dde0672b d2441d3e

MAINTAINERS

+2 −0
Original line number Diff line number Diff line
@@ -12189,6 +12189,8 @@ LINUX FOR POWERPC (32-BIT AND 64-BIT) 
M:	Michael Ellerman <mpe@ellerman.id.au>

R:	Nicholas Piggin <npiggin@gmail.com>

R:	Christophe Leroy <christophe.leroy@csgroup.eu>

R:	Aneesh Kumar K.V <aneesh.kumar@kernel.org>

R:	Naveen N. Rao <naveen.n.rao@linux.ibm.com>

L:	linuxppc-dev@lists.ozlabs.org

S:	Supported

W:	https://github.com/linuxppc/wiki/wiki

arch/powerpc/platforms/pseries/vas.c

+44 −7
Original line number Diff line number Diff line
@@ -385,11 +385,15 @@ static struct vas_window *vas_allocate_window(int vas_id, u64 flags, 
	 * same fault IRQ is not freed by the OS before.

	 */

	mutex_lock(&vas_pseries_mutex);

	if (migration_in_progress)

	if (migration_in_progress) {

		rc = -EBUSY;

	else

	} else {

		rc = allocate_setup_window(txwin, (u64 *)&domain[0],

				   cop_feat_caps->win_type);

		if (!rc)

			caps->nr_open_wins_progress++;

	}



	mutex_unlock(&vas_pseries_mutex);

	if (rc)

		goto out;
@@ -404,8 +408,17 @@ static struct vas_window *vas_allocate_window(int vas_id, u64 flags, 
		goto out_free;



	txwin->win_type = cop_feat_caps->win_type;

	mutex_lock(&vas_pseries_mutex);



	/*

	 * The migration SUSPEND thread sets migration_in_progress and

	 * closes all open windows from the list. But the window is

	 * added to the list after open and modify HCALLs. So possible

	 * that migration_in_progress is set before modify HCALL which

	 * may cause some windows are still open when the hypervisor

	 * initiates the migration.

	 * So checks the migration_in_progress flag again and close all

	 * open windows.

	 *

	 * Possible to lose the acquired credit with DLPAR core

	 * removal after the window is opened. So if there are any

	 * closed windows (means with lost credits), do not give new
@@ -413,9 +426,11 @@ static struct vas_window *vas_allocate_window(int vas_id, u64 flags, 
	 * after the existing windows are reopened when credits are

	 * available.

	 */

	if (!caps->nr_close_wins) {

	mutex_lock(&vas_pseries_mutex);

	if (!caps->nr_close_wins && !migration_in_progress) {

		list_add(&txwin->win_list, &caps->list);

		caps->nr_open_windows++;

		caps->nr_open_wins_progress--;

		mutex_unlock(&vas_pseries_mutex);

		vas_user_win_add_mm_context(&txwin->vas_win.task_ref);

		return &txwin->vas_win;
@@ -433,6 +448,12 @@ static struct vas_window *vas_allocate_window(int vas_id, u64 flags, 
	 */

	free_irq_setup(txwin);

	h_deallocate_vas_window(txwin->vas_win.winid);

	/*

	 * Hold mutex and reduce nr_open_wins_progress counter.

	 */

	mutex_lock(&vas_pseries_mutex);

	caps->nr_open_wins_progress--;

	mutex_unlock(&vas_pseries_mutex);

out:

	atomic_dec(&cop_feat_caps->nr_used_credits);

	kfree(txwin);
@@ -937,14 +958,14 @@ int vas_migration_handler(int action) 
	struct vas_caps *vcaps;

	int i, rc = 0;



	pr_info("VAS migration event %d\n", action);



	/*

	 * NX-GZIP is not enabled. Nothing to do for migration.

	 */

	if (!copypaste_feat)

		return rc;



	mutex_lock(&vas_pseries_mutex);



	if (action == VAS_SUSPEND)

		migration_in_progress = true;

	else
@@ -990,12 +1011,27 @@ int vas_migration_handler(int action) 


		switch (action) {

		case VAS_SUSPEND:

			mutex_lock(&vas_pseries_mutex);

			rc = reconfig_close_windows(vcaps, vcaps->nr_open_windows,

							true);

			/*

			 * Windows are included in the list after successful

			 * open. So wait for closing these in-progress open

			 * windows in vas_allocate_window() which will be

			 * done if the migration_in_progress is set.

			 */

			while (vcaps->nr_open_wins_progress) {

				mutex_unlock(&vas_pseries_mutex);

				msleep(10);

				mutex_lock(&vas_pseries_mutex);

			}

			mutex_unlock(&vas_pseries_mutex);

			break;

		case VAS_RESUME:

			mutex_lock(&vas_pseries_mutex);

			atomic_set(&caps->nr_total_credits, new_nr_creds);

			rc = reconfig_open_windows(vcaps, new_nr_creds, true);

			mutex_unlock(&vas_pseries_mutex);

			break;

		default:

			/* should not happen */
@@ -1011,8 +1047,9 @@ int vas_migration_handler(int action) 
			goto out;

	}



	pr_info("VAS migration event (%d) successful\n", action);



out:

	mutex_unlock(&vas_pseries_mutex);

	return rc;

}

arch/powerpc/platforms/pseries/vas.h

+2 −0
Original line number Diff line number Diff line
@@ -91,6 +91,8 @@ struct vas_cop_feat_caps { 
struct vas_caps {

	struct vas_cop_feat_caps caps;

	struct list_head list;	/* List of open windows */

	int nr_open_wins_progress;	/* Number of open windows in */

					/* progress. Used in migration */

	int nr_close_wins;	/* closed windows in the hypervisor for DLPAR */

	int nr_open_windows;	/* Number of successful open windows */

	u8 feat;		/* Feature type */