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

Pull virtio barrier rework+fixes from Michael Tsirkin:
 "This adds a new kind of barrier, and reworks virtio and xen to use it.

  Plus some fixes here and there"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost: (44 commits)
  checkpatch: add virt barriers
  checkpatch: check for __smp outside barrier.h
  checkpatch.pl: add missing memory barriers
  virtio: make find_vqs() checkpatch.pl-friendly
  virtio_balloon: fix race between migration and ballooning
  virtio_balloon: fix race by fill and leak
  s390: more efficient smp barriers
  s390: use generic memory barriers
  xen/events: use virt_xxx barriers
  xen/io: use virt_xxx barriers
  xenbus: use virt_xxx barriers
  virtio_ring: use virt_store_mb
  sh: move xchg_cmpxchg to a header by itself
  sh: support 1 and 2 byte xchg
  virtio_ring: update weak barriers to use virt_xxx
  Revert "virtio_ring: Update weak barriers to use dma_wmb/rmb"
  asm-generic: implement virt_xxx memory barriers
  x86: define __smp_xxx
  xtensa: define __smp_xxx
  tile: define __smp_xxx
  ...

1 files changed, 32 insertions, 1 deletions

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 2b3c22808c3b..c7bf1aa2eeb3 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -5116,13 +5116,44 @@ sub process {
                         }
                 }
 # check for memory barriers without a comment.
-                if ($line =~ /\b(mb|rmb|wmb|read_barrier_depends|smp_mb|smp_rmb|smp_wmb|smp_read_barrier_depends)\(/) {
+
+                my $barriers = qr{
+                        mb|
+                        rmb|
+                        wmb|
+                        read_barrier_depends
+                }x;
+                my $barrier_stems = qr{
+                        mb__before_atomic|
+                        mb__after_atomic|
+                        store_release|
+                        load_acquire|
+                        store_mb|
+                        (?:$barriers)
+                }x;
+                my $all_barriers = qr{
+                        (?:$barriers)|
+                        smp_(?:$barrier_stems)|
+                        virt_(?:$barrier_stems)
+                }x;
+
+                if ($line =~ /\b(?:$all_barriers)\s*\(/) {
                         if (!ctx_has_comment($first_line, $linenr)) {
                                 WARN("MEMORY_BARRIER",
                                      "memory barrier without comment\n" . $herecurr);
                         }
                 }
 
+                my $underscore_smp_barriers = qr{__smp_(?:$barrier_stems)}x;
+
+                if ($realfile !~ m@^include/asm-generic/@ &&
+                    $realfile !~ m@/barrier\.h$@ &&
+                    $line =~ m/\b(?:$underscore_smp_barriers)\s*\(/ &&
+                    $line !~ m/^.\s*\#\s*define\s+(?:$underscore_smp_barriers)\s*\(/) {
+                        WARN("MEMORY_BARRIER",
+                             "__smp memory barriers shouldn't be used outside barrier.h and asm-generic\n" . $herecurr);
+                }
+
 # check for waitqueue_active without a comment.
                 if ($line =~ /\bwaitqueue_active\s*\(/) {
                         if (!ctx_has_comment($first_line, $linenr)) {