[PATCH 6.1.y 1/2] vfio/pci: Use bitfield for struct vfio_pci_core_device flags

[Sasha Levin <sashal@kernel.org>]

From: Reinette Chatre <reinette.chatre@intel.com>

[ Upstream commit 9cd0f6d5cbb6fda09aa83beb8146c287a552017e ]

struct vfio_pci_core_device contains eleven boolean flags.
Boolean flags clearly indicate their usage but space usage
starts to be a concern when there are many.

An upcoming change adds another boolean flag to
struct vfio_pci_core_device, thereby increasing the concern
that the boolean flags are consuming unnecessary space.

Transition the boolean flags to use bitfields. On a system that
uses one byte per boolean this reduces the space consumed
by existing flags from 11 bytes to 2 bytes with room for
a few more flags without increasing the structure's size.

Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/cf34bf0499c889554a8105eeb18cc0ab673005be.1683740667.git.reinette.chatre@intel.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Stable-dep-of: 40ef3edf151e ("vfio/pci: Use a private flag to prevent power state change with VFs")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 include/linux/vfio_pci_core.h | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/include/linux/vfio_pci_core.h b/include/linux/vfio_pci_core.h
index 367fd79226a306..1c56c1df163cca 100644
--- a/include/linux/vfio_pci_core.h
+++ b/include/linux/vfio_pci_core.h
@@ -69,17 +69,17 @@ struct vfio_pci_core_device {
 	u16			msix_size;
 	u32			msix_offset;
 	u32			rbar[7];
-	bool			pci_2_3;
-	bool			virq_disabled;
-	bool			reset_works;
-	bool			extended_caps;
-	bool			bardirty;
-	bool			has_vga;
-	bool			needs_reset;
-	bool			nointx;
-	bool			needs_pm_restore;
-	bool			pm_intx_masked;
-	bool			pm_runtime_engaged;
+	bool			pci_2_3:1;
+	bool			virq_disabled:1;
+	bool			reset_works:1;
+	bool			extended_caps:1;
+	bool			bardirty:1;
+	bool			has_vga:1;
+	bool			needs_reset:1;
+	bool			nointx:1;
+	bool			needs_pm_restore:1;
+	bool			pm_intx_masked:1;
+	bool			pm_runtime_engaged:1;
 	struct pci_saved_state	*pci_saved_state;
 	struct pci_saved_state	*pm_save;
 	int			ioeventfds_nr;
-- 
2.53.0