Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

net/mptcp/protocol.c
  977d293e23b4 ("mptcp: ensure tx skbs always have the MPTCP ext")
  efe686ffce01 ("mptcp: ensure tx skbs always have the MPTCP ext")

same patch merged in both trees, keep net-next.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>

4 files changed, 50 insertions, 23 deletions

diff --git a/kernel/dma/debug.c b/kernel/dma/debug.c
index 6c90c69e5311..95445bd6eb72 100644
--- a/kernel/dma/debug.c
+++ b/kernel/dma/debug.c
@@ -567,7 +567,8 @@ static void add_dma_entry(struct dma_debug_entry *entry)
 		pr_err("cacheline tracking ENOMEM, dma-debug disabled\n");
 		global_disable = true;
 	} else if (rc == -EEXIST) {
-		pr_err("cacheline tracking EEXIST, overlapping mappings aren't supported\n");
+		err_printk(entry->dev, entry,
+			"cacheline tracking EEXIST, overlapping mappings aren't supported\n");
 	}
 }
 
diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index 7ee5284bff58..06fec5547e7c 100644
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c
@@ -206,7 +206,8 @@ static int __dma_map_sg_attrs(struct device *dev, struct scatterlist *sg,
 /**
  * dma_map_sg_attrs - Map the given buffer for DMA
  * @dev:	The device for which to perform the DMA operation
- * @sg:	The sg_table object describing the buffer
+ * @sg:		The sg_table object describing the buffer
+ * @nents:	Number of entries to map
  * @dir:	DMA direction
  * @attrs:	Optional DMA attributes for the map operation
  *
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 349f80aa9e7d..20367196fa9a 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -10193,7 +10193,7 @@ static void perf_event_addr_filters_apply(struct perf_event *event)
 		return;
 
 	if (ifh->nr_file_filters) {
-		mm = get_task_mm(event->ctx->task);
+		mm = get_task_mm(task);
 		if (!mm)
 			goto restart;
 
diff --git a/kernel/locking/rwbase_rt.c b/kernel/locking/rwbase_rt.c
index 4ba15088e640..88191f6e252c 100644
--- a/kernel/locking/rwbase_rt.c
+++ b/kernel/locking/rwbase_rt.c
@@ -41,6 +41,12 @@
  * The risk of writer starvation is there, but the pathological use cases
  * which trigger it are not necessarily the typical RT workloads.
  *
+ * Fast-path orderings:
+ * The lock/unlock of readers can run in fast paths: lock and unlock are only
+ * atomic ops, and there is no inner lock to provide ACQUIRE and RELEASE
+ * semantics of rwbase_rt. Atomic ops should thus provide _acquire()
+ * and _release() (or stronger).
+ *
  * Common code shared between RT rw_semaphore and rwlock
  */
 
@@ -53,6 +59,7 @@ static __always_inline int rwbase_read_trylock(struct rwbase_rt *rwb)
 	 * set.
 	 */
 	for (r = atomic_read(&rwb->readers); r < 0;) {
+		/* Fully-ordered if cmpxchg() succeeds, provides ACQUIRE */
 		if (likely(atomic_try_cmpxchg(&rwb->readers, &r, r + 1)))
 			return 1;
 	}
@@ -162,6 +169,8 @@ static __always_inline void rwbase_read_unlock(struct rwbase_rt *rwb,
 	/*
 	 * rwb->readers can only hit 0 when a writer is waiting for the
 	 * active readers to leave the critical section.
+	 *
+	 * dec_and_test() is fully ordered, provides RELEASE.
 	 */
 	if (unlikely(atomic_dec_and_test(&rwb->readers)))
 		__rwbase_read_unlock(rwb, state);
@@ -172,7 +181,11 @@ static inline void __rwbase_write_unlock(struct rwbase_rt *rwb, int bias,
 {
 	struct rt_mutex_base *rtm = &rwb->rtmutex;
 
-	atomic_add(READER_BIAS - bias, &rwb->readers);
+	/*
+	 * _release() is needed in case that reader is in fast path, pairing
+	 * with atomic_try_cmpxchg() in rwbase_read_trylock(), provides RELEASE
+	 */
+	(void)atomic_add_return_release(READER_BIAS - bias, &rwb->readers);
 	raw_spin_unlock_irqrestore(&rtm->wait_lock, flags);
 	rwbase_rtmutex_unlock(rtm);
 }
@@ -196,6 +209,23 @@ static inline void rwbase_write_downgrade(struct rwbase_rt *rwb)
 	__rwbase_write_unlock(rwb, WRITER_BIAS - 1, flags);
 }
 
+static inline bool __rwbase_write_trylock(struct rwbase_rt *rwb)
+{
+	/* Can do without CAS because we're serialized by wait_lock. */
+	lockdep_assert_held(&rwb->rtmutex.wait_lock);
+
+	/*
+	 * _acquire is needed in case the reader is in the fast path, pairing
+	 * with rwbase_read_unlock(), provides ACQUIRE.
+	 */
+	if (!atomic_read_acquire(&rwb->readers)) {
+		atomic_set(&rwb->readers, WRITER_BIAS);
+		return 1;
+	}
+
+	return 0;
+}
+
 static int __sched rwbase_write_lock(struct rwbase_rt *rwb,
 				     unsigned int state)
 {
@@ -210,34 +240,30 @@ static int __sched rwbase_write_lock(struct rwbase_rt *rwb,
 	atomic_sub(READER_BIAS, &rwb->readers);
 
 	raw_spin_lock_irqsave(&rtm->wait_lock, flags);
-	/*
-	 * set_current_state() for rw_semaphore
-	 * current_save_and_set_rtlock_wait_state() for rwlock
-	 */
-	rwbase_set_and_save_current_state(state);
+	if (__rwbase_write_trylock(rwb))
+		goto out_unlock;
 
-	/* Block until all readers have left the critical section. */
-	for (; atomic_read(&rwb->readers);) {
+	rwbase_set_and_save_current_state(state);
+	for (;;) {
 		/* Optimized out for rwlocks */
 		if (rwbase_signal_pending_state(state, current)) {
-			__set_current_state(TASK_RUNNING);
+			rwbase_restore_current_state();
 			__rwbase_write_unlock(rwb, 0, flags);
 			return -EINTR;
 		}
+
+		if (__rwbase_write_trylock(rwb))
+			break;
+
 		raw_spin_unlock_irqrestore(&rtm->wait_lock, flags);
+		rwbase_schedule();
+		raw_spin_lock_irqsave(&rtm->wait_lock, flags);
 
-		/*
-		 * Schedule and wait for the readers to leave the critical
-		 * section. The last reader leaving it wakes the waiter.
-		 */
-		if (atomic_read(&rwb->readers) != 0)
-			rwbase_schedule();
 		set_current_state(state);
-		raw_spin_lock_irqsave(&rtm->wait_lock, flags);
 	}
-
-	atomic_set(&rwb->readers, WRITER_BIAS);
 	rwbase_restore_current_state();
+
+out_unlock:
 	raw_spin_unlock_irqrestore(&rtm->wait_lock, flags);
 	return 0;
 }
@@ -253,8 +279,7 @@ static inline int rwbase_write_trylock(struct rwbase_rt *rwb)
 	atomic_sub(READER_BIAS, &rwb->readers);
 
 	raw_spin_lock_irqsave(&rtm->wait_lock, flags);
-	if (!atomic_read(&rwb->readers)) {
-		atomic_set(&rwb->readers, WRITER_BIAS);
+	if (__rwbase_write_trylock(rwb)) {
 		raw_spin_unlock_irqrestore(&rtm->wait_lock, flags);
 		return 1;
 	}