Merge tag 'zynqmp-soc-fixes-for-v5.10-rc6' of https://github.com/Xilinx/linux-xlnx into arm/fixes

arm64: soc: ZynqMP SoC fixes for v5.10-rc6

- Fix SD dll reset issue by using proper macro
- Fix PM feature checking for Xilinx Versal SoC

* tag 'zynqmp-soc-fixes-for-v5.10-rc6' of https://github.com/Xilinx/linux-xlnx: (337 commits)
  firmware: xilinx: Use hash-table for api feature check
  firmware: xilinx: Fix SD DLL node reset issue
  Linux 5.10-rc4
  kvm: mmu: fix is_tdp_mmu_check when the TDP MMU is not in use
  afs: Fix afs_write_end() when called with copied == 0 [ver #3]
  ocfs2: initialize ip_next_orphan
  panic: don't dump stack twice on warn
  hugetlbfs: fix anon huge page migration race
  mm: memcontrol: fix missing wakeup polling thread
  kernel/watchdog: fix watchdog_allowed_mask not used warning
  reboot: fix overflow parsing reboot cpu number
  Revert "kernel/reboot.c: convert simple_strtoul to kstrtoint"
  compiler.h: fix barrier_data() on clang
  mm/gup: use unpin_user_pages() in __gup_longterm_locked()
  mm/slub: fix panic in slab_alloc_node()
  mailmap: fix entry for Dmitry Baryshkov/Eremin-Solenikov
  mm/vmscan: fix NR_ISOLATED_FILE corruption on 64-bit
  mm/compaction: stop isolation if too many pages are isolated and we have pages to migrate
  mm/compaction: count pages and stop correctly during page isolation
  drm/nouveau/kms/nv50-: Use atomic encoder callbacks everywhere
  ...

Link: https://lore.kernel.org/r/fd5ab967-f3cf-95fb-7947-5477ff85f97e@monstr.eu
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 9 insertions, 10 deletions

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index b71ad8d9f1c9..d9fb9e19d2ed 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -2765,7 +2765,9 @@ print_deadlock_bug(struct task_struct *curr, struct held_lock *prev,
  * (Note that this has to be done separately, because the graph cannot
  * detect such classes of deadlocks.)
  *
- * Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read
+ * Returns: 0 on deadlock detected, 1 on OK, 2 if another lock with the same
+ * lock class is held but nest_lock is also held, i.e. we rely on the
+ * nest_lock to avoid the deadlock.
  */
 static int
 check_deadlock(struct task_struct *curr, struct held_lock *next)
@@ -2788,7 +2790,7 @@ check_deadlock(struct task_struct *curr, struct held_lock *next)
 		 * lock class (i.e. read_lock(lock)+read_lock(lock)):
 		 */
 		if ((next->read == 2) && prev->read)
-			return 2;
+			continue;
 
 		/*
 		 * We're holding the nest_lock, which serializes this lock's
@@ -3593,15 +3595,12 @@ static int validate_chain(struct task_struct *curr,
 		if (!ret)
 			return 0;
 		/*
-		 * Mark recursive read, as we jump over it when
-		 * building dependencies (just like we jump over
-		 * trylock entries):
-		 */
-		if (ret == 2)
-			hlock->read = 2;
-		/*
 		 * Add dependency only if this lock is not the head
-		 * of the chain, and if it's not a secondary read-lock:
+		 * of the chain, and if the new lock introduces no more
+		 * lock dependency (because we already hold a lock with the
+		 * same lock class) nor deadlock (because the nest_lock
+		 * serializes nesting locks), see the comments for
+		 * check_deadlock().
 		 */
 		if (!chain_head && ret != 2) {
 			if (!check_prevs_add(curr, hlock))