Merge tag 'locking-core-2020-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull locking updates from Ingo Molnar:

 - LKMM updates: mostly documentation changes, but also some new litmus
   tests for atomic ops.

 - KCSAN updates: the most important change is that GCC 11 now has all
   fixes in place to support KCSAN, so GCC support can be enabled again.
   Also more annotations.

 - futex updates: minor cleanups and simplifications

 - seqlock updates: merge preparatory changes/cleanups for the
   'associated locks' facilities.

 - lockdep updates:
    - simplify IRQ trace event handling
    - add various new debug checks
    - simplify header dependencies, split out <linux/lockdep_types.h>,
      decouple lockdep from other low level headers some more
    - fix NMI handling

 - misc cleanups and smaller fixes

* tag 'locking-core-2020-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (60 commits)
  kcsan: Improve IRQ state trace reporting
  lockdep: Refactor IRQ trace events fields into struct
  seqlock: lockdep assert non-preemptibility on seqcount_t write
  lockdep: Add preemption enabled/disabled assertion APIs
  seqlock: Implement raw_seqcount_begin() in terms of raw_read_seqcount()
  seqlock: Add kernel-doc for seqcount_t and seqlock_t APIs
  seqlock: Reorder seqcount_t and seqlock_t API definitions
  seqlock: seqcount_t latch: End read sections with read_seqcount_retry()
  seqlock: Properly format kernel-doc code samples
  Documentation: locking: Describe seqlock design and usage
  locking/qspinlock: Do not include atomic.h from qspinlock_types.h
  locking/atomic: Move ATOMIC_INIT into linux/types.h
  lockdep: Move list.h inclusion into lockdep.h
  locking/lockdep: Fix TRACE_IRQFLAGS vs. NMIs
  futex: Remove unused or redundant includes
  futex: Consistently use fshared as boolean
  futex: Remove needless goto's
  futex: Remove put_futex_key()
  rwsem: fix commas in initialisation
  docs: locking: Replace HTTP links with HTTPS ones
  ...

1 files changed, 26 insertions, 88 deletions

diff --git a/kernel/futex.c b/kernel/futex.c
index e646661f6282..4616d4ad609d 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -32,30 +32,13 @@
  *  "But they come in a choice of three flavours!"
  */
 #include <linux/compat.h>
-#include <linux/slab.h>
-#include <linux/poll.h>
-#include <linux/fs.h>
-#include <linux/file.h>
 #include <linux/jhash.h>
-#include <linux/init.h>
-#include <linux/futex.h>
-#include <linux/mount.h>
 #include <linux/pagemap.h>
 #include <linux/syscalls.h>
-#include <linux/signal.h>
-#include <linux/export.h>
-#include <linux/magic.h>
-#include <linux/pid.h>
-#include <linux/nsproxy.h>
-#include <linux/ptrace.h>
-#include <linux/sched/rt.h>
-#include <linux/sched/wake_q.h>
-#include <linux/sched/mm.h>
 #include <linux/hugetlb.h>
 #include <linux/freezer.h>
 #include <linux/memblock.h>
 #include <linux/fault-inject.h>
-#include <linux/refcount.h>
 
 #include <asm/futex.h>
 
@@ -476,7 +459,7 @@ static u64 get_inode_sequence_number(struct inode *inode)
 /**
  * get_futex_key() - Get parameters which are the keys for a futex
  * @uaddr:	virtual address of the futex
- * @fshared:	0 for a PROCESS_PRIVATE futex, 1 for PROCESS_SHARED
+ * @fshared:	false for a PROCESS_PRIVATE futex, true for PROCESS_SHARED
  * @key:	address where result is stored.
  * @rw:		mapping needs to be read/write (values: FUTEX_READ,
  *              FUTEX_WRITE)
@@ -500,8 +483,8 @@ static u64 get_inode_sequence_number(struct inode *inode)
  *
  * lock_page() might sleep, the caller should not hold a spinlock.
  */
-static int
-get_futex_key(u32 __user *uaddr, int fshared, union futex_key *key, enum futex_access rw)
+static int get_futex_key(u32 __user *uaddr, bool fshared, union futex_key *key,
+			 enum futex_access rw)
 {
 	unsigned long address = (unsigned long)uaddr;
 	struct mm_struct *mm = current->mm;
@@ -538,7 +521,7 @@ get_futex_key(u32 __user *uaddr, int fshared, union futex_key *key, enum futex_a
 
 again:
 	/* Ignore any VERIFY_READ mapping (futex common case) */
-	if (unlikely(should_fail_futex(fshared)))
+	if (unlikely(should_fail_futex(true)))
 		return -EFAULT;
 
 	err = get_user_pages_fast(address, 1, FOLL_WRITE, &page);
@@ -626,7 +609,7 @@ again:
 		 * A RO anonymous page will never change and thus doesn't make
 		 * sense for futex operations.
 		 */
-		if (unlikely(should_fail_futex(fshared)) || ro) {
+		if (unlikely(should_fail_futex(true)) || ro) {
 			err = -EFAULT;
 			goto out;
 		}
@@ -677,10 +660,6 @@ out:
 	return err;
 }
 
-static inline void put_futex_key(union futex_key *key)
-{
-}
-
 /**
  * fault_in_user_writeable() - Fault in user address and verify RW access
  * @uaddr:	pointer to faulting user space address
@@ -1611,13 +1590,13 @@ futex_wake(u32 __user *uaddr, unsigned int flags, int nr_wake, u32 bitset)
 
 	ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &key, FUTEX_READ);
 	if (unlikely(ret != 0))
-		goto out;
+		return ret;
 
 	hb = hash_futex(&key);
 
 	/* Make sure we really have tasks to wakeup */
 	if (!hb_waiters_pending(hb))
-		goto out_put_key;
+		return ret;
 
 	spin_lock(&hb->lock);
 
@@ -1640,9 +1619,6 @@ futex_wake(u32 __user *uaddr, unsigned int flags, int nr_wake, u32 bitset)
 
 	spin_unlock(&hb->lock);
 	wake_up_q(&wake_q);
-out_put_key:
-	put_futex_key(&key);
-out:
 	return ret;
 }
 
@@ -1709,10 +1685,10 @@ futex_wake_op(u32 __user *uaddr1, unsigned int flags, u32 __user *uaddr2,
 retry:
 	ret = get_futex_key(uaddr1, flags & FLAGS_SHARED, &key1, FUTEX_READ);
 	if (unlikely(ret != 0))
-		goto out;
+		return ret;
 	ret = get_futex_key(uaddr2, flags & FLAGS_SHARED, &key2, FUTEX_WRITE);
 	if (unlikely(ret != 0))
-		goto out_put_key1;
+		return ret;
 
 	hb1 = hash_futex(&key1);
 	hb2 = hash_futex(&key2);
@@ -1730,13 +1706,13 @@ retry_private:
 			 * an MMU, but we might get them from range checking
 			 */
 			ret = op_ret;
-			goto out_put_keys;
+			return ret;
 		}
 
 		if (op_ret == -EFAULT) {
 			ret = fault_in_user_writeable(uaddr2);
 			if (ret)
-				goto out_put_keys;
+				return ret;
 		}
 
 		if (!(flags & FLAGS_SHARED)) {
@@ -1744,8 +1720,6 @@ retry_private:
 			goto retry_private;
 		}
 
-		put_futex_key(&key2);
-		put_futex_key(&key1);
 		cond_resched();
 		goto retry;
 	}
@@ -1781,11 +1755,6 @@ retry_private:
 out_unlock:
 	double_unlock_hb(hb1, hb2);
 	wake_up_q(&wake_q);
-out_put_keys:
-	put_futex_key(&key2);
-out_put_key1:
-	put_futex_key(&key1);
-out:
 	return ret;
 }
 
@@ -1992,20 +1961,18 @@ static int futex_requeue(u32 __user *uaddr1, unsigned int flags,
 retry:
 	ret = get_futex_key(uaddr1, flags & FLAGS_SHARED, &key1, FUTEX_READ);
 	if (unlikely(ret != 0))
-		goto out;
+		return ret;
 	ret = get_futex_key(uaddr2, flags & FLAGS_SHARED, &key2,
 			    requeue_pi ? FUTEX_WRITE : FUTEX_READ);
 	if (unlikely(ret != 0))
-		goto out_put_key1;
+		return ret;
 
 	/*
 	 * The check above which compares uaddrs is not sufficient for
 	 * shared futexes. We need to compare the keys:
 	 */
-	if (requeue_pi && match_futex(&key1, &key2)) {
-		ret = -EINVAL;
-		goto out_put_keys;
-	}
+	if (requeue_pi && match_futex(&key1, &key2))
+		return -EINVAL;
 
 	hb1 = hash_futex(&key1);
 	hb2 = hash_futex(&key2);
@@ -2025,13 +1992,11 @@ retry_private:
 
 			ret = get_user(curval, uaddr1);
 			if (ret)
-				goto out_put_keys;
+				return ret;
 
 			if (!(flags & FLAGS_SHARED))
 				goto retry_private;
 
-			put_futex_key(&key2);
-			put_futex_key(&key1);
 			goto retry;
 		}
 		if (curval != *cmpval) {
@@ -2090,12 +2055,10 @@ retry_private:
 		case -EFAULT:
 			double_unlock_hb(hb1, hb2);
 			hb_waiters_dec(hb2);
-			put_futex_key(&key2);
-			put_futex_key(&key1);
 			ret = fault_in_user_writeable(uaddr2);
 			if (!ret)
 				goto retry;
-			goto out;
+			return ret;
 		case -EBUSY:
 		case -EAGAIN:
 			/*
@@ -2106,8 +2069,6 @@ retry_private:
 			 */
 			double_unlock_hb(hb1, hb2);
 			hb_waiters_dec(hb2);
-			put_futex_key(&key2);
-			put_futex_key(&key1);
 			/*
 			 * Handle the case where the owner is in the middle of
 			 * exiting. Wait for the exit to complete otherwise
@@ -2216,12 +2177,6 @@ out_unlock:
 	double_unlock_hb(hb1, hb2);
 	wake_up_q(&wake_q);
 	hb_waiters_dec(hb2);
-
-out_put_keys:
-	put_futex_key(&key2);
-out_put_key1:
-	put_futex_key(&key1);
-out:
 	return ret ? ret : task_count;
 }
 
@@ -2567,7 +2522,7 @@ static int fixup_owner(u32 __user *uaddr, struct futex_q *q, int locked)
 		 */
 		if (q->pi_state->owner != current)
 			ret = fixup_pi_state_owner(uaddr, q, current);
-		goto out;
+		return ret ? ret : locked;
 	}
 
 	/*
@@ -2580,7 +2535,7 @@ static int fixup_owner(u32 __user *uaddr, struct futex_q *q, int locked)
 	 */
 	if (q->pi_state->owner == current) {
 		ret = fixup_pi_state_owner(uaddr, q, NULL);
-		goto out;
+		return ret;
 	}
 
 	/*
@@ -2594,8 +2549,7 @@ static int fixup_owner(u32 __user *uaddr, struct futex_q *q, int locked)
 				q->pi_state->owner);
 	}
 
-out:
-	return ret ? ret : locked;
+	return ret;
 }
 
 /**
@@ -2692,12 +2646,11 @@ retry_private:
 
 		ret = get_user(uval, uaddr);
 		if (ret)
-			goto out;
+			return ret;
 
 		if (!(flags & FLAGS_SHARED))
 			goto retry_private;
 
-		put_futex_key(&q->key);
 		goto retry;
 	}
 
@@ -2706,9 +2659,6 @@ retry_private:
 		ret = -EWOULDBLOCK;
 	}
 
-out:
-	if (ret)
-		put_futex_key(&q->key);
 	return ret;
 }
 
@@ -2853,7 +2803,6 @@ retry_private:
 			 * - EAGAIN: The user space value changed.
 			 */
 			queue_unlock(hb);
-			put_futex_key(&q.key);
 			/*
 			 * Handle the case where the owner is in the middle of
 			 * exiting. Wait for the exit to complete otherwise
@@ -2961,13 +2910,11 @@ no_block:
 		put_pi_state(pi_state);
 	}
 
-	goto out_put_key;
+	goto out;
 
 out_unlock_put_key:
 	queue_unlock(hb);
 
-out_put_key:
-	put_futex_key(&q.key);
 out:
 	if (to) {
 		hrtimer_cancel(&to->timer);
@@ -2980,12 +2927,11 @@ uaddr_faulted:
 
 	ret = fault_in_user_writeable(uaddr);
 	if (ret)
-		goto out_put_key;
+		goto out;
 
 	if (!(flags & FLAGS_SHARED))
 		goto retry_private;
 
-	put_futex_key(&q.key);
 	goto retry;
 }
 
@@ -3114,16 +3060,13 @@ retry:
 out_unlock:
 	spin_unlock(&hb->lock);
 out_putkey:
-	put_futex_key(&key);
 	return ret;
 
 pi_retry:
-	put_futex_key(&key);
 	cond_resched();
 	goto retry;
 
 pi_faulted:
-	put_futex_key(&key);
 
 	ret = fault_in_user_writeable(uaddr);
 	if (!ret)
@@ -3265,7 +3208,7 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags,
 	 */
 	ret = futex_wait_setup(uaddr, val, flags, &q, &hb);
 	if (ret)
-		goto out_key2;
+		goto out;
 
 	/*
 	 * The check above which compares uaddrs is not sufficient for
@@ -3274,7 +3217,7 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags,
 	if (match_futex(&q.key, &key2)) {
 		queue_unlock(hb);
 		ret = -EINVAL;
-		goto out_put_keys;
+		goto out;
 	}
 
 	/* Queue the futex_q, drop the hb lock, wait for wakeup. */
@@ -3284,7 +3227,7 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags,
 	ret = handle_early_requeue_pi_wakeup(hb, &q, &key2, to);
 	spin_unlock(&hb->lock);
 	if (ret)
-		goto out_put_keys;
+		goto out;
 
 	/*
 	 * In order for us to be here, we know our q.key == key2, and since
@@ -3374,11 +3317,6 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags,
 		ret = -EWOULDBLOCK;
 	}
 
-out_put_keys:
-	put_futex_key(&q.key);
-out_key2:
-	put_futex_key(&key2);
-
 out:
 	if (to) {
 		hrtimer_cancel(&to->timer);