PM: hibernate: Restrict GFP mask in power_down()

Commit 12ffc3b151 ("PM: Restrict swap use to later in the
suspend sequence") caused hibernation_platform_enter() to call
pm_restore_gfp_mask() via dpm_resume_end(), so when power_down()
returns after aborting hibernation_platform_enter(), it needs
to match the pm_restore_gfp_mask() call in hibernate() that will
occur subsequently.

Address this by adding a pm_restrict_gfp_mask() call to the relevant
error path in power_down().

Fixes: 12ffc3b151 ("PM: Restrict swap use to later in the suspend sequence")
Cc: 6.16+ <stable@vger.kernel.org> # 6.16+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>

kernel/power/hibernate.c

@@ -733,6 +733,8 @@ static void power_down(void)
 	case HIBERNATION_PLATFORM:
 		error = hibernation_platform_enter();
 		if (error == -EAGAIN || error == -EBUSY) {
+			/* Match pm_restore_gfp_mask() in hibernate(). */
+			pm_restrict_gfp_mask();
 			swsusp_unmark();
 			events_check_enabled = false;
 			pr_info("Wakeup event detected during hibernation, rolling back.\n");