[PATCH RT 08/24] Revert "x86: UV: raw_spinlock conversion"

[Steven Rostedt <rostedt@goodmis.org>]

4.14.63-rt41-rc2 stable review patch.
If anyone has any objections, please let me know.

------------------

From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

[ Upstream commit 2a9c45d8f89112458364285cbe2b0729561953f1 ]

Drop the Ultraviolet patch. UV looks broken upstream for PREEMPT, too.
Mike is the only person I know that has such a thing and he isn't going
to fix this upstream (from 1526977462.6491.1.camel@gmx.de):

|From: Mike Galbraith <gleep@gmx.de>
|On Tue, 2018-05-22 at 08:50 +0200, Sebastian Andrzej Siewior wrote:
|>
|> Regarding the preempt_disable() in the original patch in uv_read_rtc():
|> This looks essential for PREEMPT configs. Is it possible to get this
|> tested by someone or else get rid of the UV code? It looks broken for
|> "uv_get_min_hub_revision_id() != 1".
|
|I suspect SGI cares not one whit about PREEMPT.
|
|> Why does PREEMPT_RT require migrate_disable() but PREEMPT only is fine
|> as-is? This does not look right.
|
|UV is not ok with a PREEMPT config, it's just that for RT it's dirt
|simple to shut it up, whereas for PREEMPT, preempt_disable() across
|uv_bau_init() doesn't cut it due to allocations, and whatever else I
|would have met before ending the whack-a-mole game.
|
|If I were in your shoes, I think I'd just stop caring about UV until a
|real user appears.  AFAIK, I'm the only guy who ever ran RT on UV, and
|I only did so because SUSE asked me to look into it.. years ago now.
|
|        -Mike

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 arch/x86/include/asm/uv/uv_bau.h | 14 +++++++-------
 arch/x86/platform/uv/tlb_uv.c    | 26 +++++++++++++-------------
 arch/x86/platform/uv/uv_time.c   | 20 ++++++++------------
 3 files changed, 28 insertions(+), 32 deletions(-)

diff --git a/arch/x86/include/asm/uv/uv_bau.h b/arch/x86/include/asm/uv/uv_bau.h
index 2ac6e347bdc5..7cac79802ad2 100644
--- a/arch/x86/include/asm/uv/uv_bau.h
+++ b/arch/x86/include/asm/uv/uv_bau.h
@@ -643,9 +643,9 @@ struct bau_control {
 	cycles_t		send_message;
 	cycles_t		period_end;
 	cycles_t		period_time;
-	raw_spinlock_t		uvhub_lock;
-	raw_spinlock_t		queue_lock;
-	raw_spinlock_t		disable_lock;
+	spinlock_t		uvhub_lock;
+	spinlock_t		queue_lock;
+	spinlock_t		disable_lock;
 	/* tunables */
 	int			max_concurr;
 	int			max_concurr_const;
@@ -847,15 +847,15 @@ static inline int atom_asr(short i, struct atomic_short *v)
  * to be lowered below the current 'v'.  atomic_add_unless can only stop
  * on equal.
  */
-static inline int atomic_inc_unless_ge(raw_spinlock_t *lock, atomic_t *v, int u)
+static inline int atomic_inc_unless_ge(spinlock_t *lock, atomic_t *v, int u)
 {
-	raw_spin_lock(lock);
+	spin_lock(lock);
 	if (atomic_read(v) >= u) {
-		raw_spin_unlock(lock);
+		spin_unlock(lock);
 		return 0;
 	}
 	atomic_inc(v);
-	raw_spin_unlock(lock);
+	spin_unlock(lock);
 	return 1;
 }
 
diff --git a/arch/x86/platform/uv/tlb_uv.c b/arch/x86/platform/uv/tlb_uv.c
index 5607611df740..34f9a9ce6236 100644
--- a/arch/x86/platform/uv/tlb_uv.c
+++ b/arch/x86/platform/uv/tlb_uv.c
@@ -740,9 +740,9 @@ static void destination_plugged(struct bau_desc *bau_desc,
 
 		quiesce_local_uvhub(hmaster);
 
-		raw_spin_lock(&hmaster->queue_lock);
+		spin_lock(&hmaster->queue_lock);
 		reset_with_ipi(&bau_desc->distribution, bcp);
-		raw_spin_unlock(&hmaster->queue_lock);
+		spin_unlock(&hmaster->queue_lock);
 
 		end_uvhub_quiesce(hmaster);
 
@@ -762,9 +762,9 @@ static void destination_timeout(struct bau_desc *bau_desc,
 
 		quiesce_local_uvhub(hmaster);
 
-		raw_spin_lock(&hmaster->queue_lock);
+		spin_lock(&hmaster->queue_lock);
 		reset_with_ipi(&bau_desc->distribution, bcp);
-		raw_spin_unlock(&hmaster->queue_lock);
+		spin_unlock(&hmaster->queue_lock);
 
 		end_uvhub_quiesce(hmaster);
 
@@ -785,7 +785,7 @@ static void disable_for_period(struct bau_control *bcp, struct ptc_stats *stat)
 	cycles_t tm1;
 
 	hmaster = bcp->uvhub_master;
-	raw_spin_lock(&hmaster->disable_lock);
+	spin_lock(&hmaster->disable_lock);
 	if (!bcp->baudisabled) {
 		stat->s_bau_disabled++;
 		tm1 = get_cycles();
@@ -798,7 +798,7 @@ static void disable_for_period(struct bau_control *bcp, struct ptc_stats *stat)
 			}
 		}
 	}
-	raw_spin_unlock(&hmaster->disable_lock);
+	spin_unlock(&hmaster->disable_lock);
 }
 
 static void count_max_concurr(int stat, struct bau_control *bcp,
@@ -861,7 +861,7 @@ static void record_send_stats(cycles_t time1, cycles_t time2,
  */
 static void uv1_throttle(struct bau_control *hmaster, struct ptc_stats *stat)
 {
-	raw_spinlock_t *lock = &hmaster->uvhub_lock;
+	spinlock_t *lock = &hmaster->uvhub_lock;
 	atomic_t *v;
 
 	v = &hmaster->active_descriptor_count;
@@ -995,7 +995,7 @@ static int check_enable(struct bau_control *bcp, struct ptc_stats *stat)
 	struct bau_control *hmaster;
 
 	hmaster = bcp->uvhub_master;
-	raw_spin_lock(&hmaster->disable_lock);
+	spin_lock(&hmaster->disable_lock);
 	if (bcp->baudisabled && (get_cycles() >= bcp->set_bau_on_time)) {
 		stat->s_bau_reenabled++;
 		for_each_present_cpu(tcpu) {
@@ -1007,10 +1007,10 @@ static int check_enable(struct bau_control *bcp, struct ptc_stats *stat)
 				tbcp->period_giveups = 0;
 			}
 		}
-		raw_spin_unlock(&hmaster->disable_lock);
+		spin_unlock(&hmaster->disable_lock);
 		return 0;
 	}
-	raw_spin_unlock(&hmaster->disable_lock);
+	spin_unlock(&hmaster->disable_lock);
 	return -1;
 }
 
@@ -1942,9 +1942,9 @@ static void __init init_per_cpu_tunables(void)
 		bcp->cong_reps			= congested_reps;
 		bcp->disabled_period		= sec_2_cycles(disabled_period);
 		bcp->giveup_limit		= giveup_limit;
-		raw_spin_lock_init(&bcp->queue_lock);
-		raw_spin_lock_init(&bcp->uvhub_lock);
-		raw_spin_lock_init(&bcp->disable_lock);
+		spin_lock_init(&bcp->queue_lock);
+		spin_lock_init(&bcp->uvhub_lock);
+		spin_lock_init(&bcp->disable_lock);
 	}
 }
 
diff --git a/arch/x86/platform/uv/uv_time.c b/arch/x86/platform/uv/uv_time.c
index badf377efc21..b082d71b08ee 100644
--- a/arch/x86/platform/uv/uv_time.c
+++ b/arch/x86/platform/uv/uv_time.c
@@ -57,7 +57,7 @@ static DEFINE_PER_CPU(struct clock_event_device, cpu_ced);
 
 /* There is one of these allocated per node */
 struct uv_rtc_timer_head {
-	raw_spinlock_t	lock;
+	spinlock_t	lock;
 	/* next cpu waiting for timer, local node relative: */
 	int		next_cpu;
 	/* number of cpus on this node: */
@@ -177,7 +177,7 @@ static __init int uv_rtc_allocate_timers(void)
 				uv_rtc_deallocate_timers();
 				return -ENOMEM;
 			}
-			raw_spin_lock_init(&head->lock);
+			spin_lock_init(&head->lock);
 			head->ncpus = uv_blade_nr_possible_cpus(bid);
 			head->next_cpu = -1;
 			blade_info[bid] = head;
@@ -231,7 +231,7 @@ static int uv_rtc_set_timer(int cpu, u64 expires)
 	unsigned long flags;
 	int next_cpu;
 
-	raw_spin_lock_irqsave(&head->lock, flags);
+	spin_lock_irqsave(&head->lock, flags);
 
 	next_cpu = head->next_cpu;
 	*t = expires;
@@ -243,12 +243,12 @@ static int uv_rtc_set_timer(int cpu, u64 expires)
 		if (uv_setup_intr(cpu, expires)) {
 			*t = ULLONG_MAX;
 			uv_rtc_find_next_timer(head, pnode);
-			raw_spin_unlock_irqrestore(&head->lock, flags);
+			spin_unlock_irqrestore(&head->lock, flags);
 			return -ETIME;
 		}
 	}
 
-	raw_spin_unlock_irqrestore(&head->lock, flags);
+	spin_unlock_irqrestore(&head->lock, flags);
 	return 0;
 }
 
@@ -267,7 +267,7 @@ static int uv_rtc_unset_timer(int cpu, int force)
 	unsigned long flags;
 	int rc = 0;
 
-	raw_spin_lock_irqsave(&head->lock, flags);
+	spin_lock_irqsave(&head->lock, flags);
 
 	if ((head->next_cpu == bcpu && uv_read_rtc(NULL) >= *t) || force)
 		rc = 1;
@@ -279,7 +279,7 @@ static int uv_rtc_unset_timer(int cpu, int force)
 			uv_rtc_find_next_timer(head, pnode);
 	}
 
-	raw_spin_unlock_irqrestore(&head->lock, flags);
+	spin_unlock_irqrestore(&head->lock, flags);
 
 	return rc;
 }
@@ -299,17 +299,13 @@ static int uv_rtc_unset_timer(int cpu, int force)
 static u64 uv_read_rtc(struct clocksource *cs)
 {
 	unsigned long offset;
-	u64 cycles;
 
-	preempt_disable();
 	if (uv_get_min_hub_revision_id() == 1)
 		offset = 0;
 	else
 		offset = (uv_blade_processor_id() * L1_CACHE_BYTES) % PAGE_SIZE;
 
-	cycles = (u64)uv_read_local_mmr(UVH_RTC | offset);
-	preempt_enable();
-	return cycles;
+	return (u64)uv_read_local_mmr(UVH_RTC | offset);
 }
 
 /*
-- 
2.18.0