Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost

Pull virtio updates from Michael Tsirkin:
 "A small number of improvements all over the place:

   - shutdown has been reworked to reset devices

   - virtio fs is now allowed in vduse

   - vhost-scsi memory use has been reduced

   - cleanups, fixes all over the place

  A couple more fixes are being tested and will be merged after rc1"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  vhost-scsi: Reduce response iov mem use
  vhost-scsi: Allocate iov_iter used for unaligned copies when needed
  vhost-scsi: Stop duplicating se_cmd fields
  vhost-scsi: Dynamically allocate scatterlists
  vhost-scsi: Return queue full for page alloc failures during copy
  vhost-scsi: Add better resource allocation failure handling
  vhost-scsi: Allocate T10 PI structs only when enabled
  vhost-scsi: Reduce mem use by moving upages to per queue
  vduse: add virtio_fs to allowed dev id
  sound/virtio: Fix cancel_sync warnings on uninitialized work_structs
  vdpa/mlx5: Fix oversized null mkey longer than 32bit
  vdpa/mlx5: Fix mlx5_vdpa_get_config() endianness on big-endian machines
  vhost-scsi: Fix handling of multiple calls to vhost_scsi_set_endpoint
  tools: virtio/linux/module.h add MODULE_DESCRIPTION() define.
  tools: virtio/linux/compiler.h: Add data_race() define.
  tools/virtio: Add DMA_MAPPING_ERROR and sg_dma_len api define for virtio test
  virtio: break and reset virtio devices on device_shutdown()

1 files changed, 25 insertions, 0 deletions

diff --git a/tools/virtio/linux/compiler.h b/tools/virtio/linux/compiler.h
index 1f3a15b954b9..204ef0e9f542 100644
--- a/tools/virtio/linux/compiler.h
+++ b/tools/virtio/linux/compiler.h
@@ -10,4 +10,29 @@
 #define READ_ONCE(var) (*((volatile typeof(var) *)(&(var))))
 
 #define __aligned(x) __attribute((__aligned__(x)))
+
+/**
+ * data_race - mark an expression as containing intentional data races
+ *
+ * This data_race() macro is useful for situations in which data races
+ * should be forgiven.  One example is diagnostic code that accesses
+ * shared variables but is not a part of the core synchronization design.
+ * For example, if accesses to a given variable are protected by a lock,
+ * except for diagnostic code, then the accesses under the lock should
+ * be plain C-language accesses and those in the diagnostic code should
+ * use data_race().  This way, KCSAN will complain if buggy lockless
+ * accesses to that variable are introduced, even if the buggy accesses
+ * are protected by READ_ONCE() or WRITE_ONCE().
+ *
+ * This macro *does not* affect normal code generation, but is a hint
+ * to tooling that data races here are to be ignored.  If the access must
+ * be atomic *and* KCSAN should ignore the access, use both data_race()
+ * and READ_ONCE(), for example, data_race(READ_ONCE(x)).
+ */
+#define data_race(expr)							\
+({									\
+	__auto_type __v = (expr);					\
+	__v;								\
+})
+
 #endif