linux-kernel - [PATCH 4.9 091/109] dma-buf/sw-sync: Reduce irqsave/irqrestore from known context

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20171207125645.152493642@linuxfoundation.org>
Date:   Thu,  7 Dec 2017 13:57:15 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Chris Wilson <chris@...is-wilson.co.uk>,
        Sumit Semwal <sumit.semwal@...aro.org>,
        Sean Paul <seanpaul@...omium.org>,
        Gustavo Padovan <gustavo@...ovan.org>,
        Gustavo Padovan <gustavo.padovan@...labora.com>,
        Jisheng Zhang <Jisheng.Zhang@...aptics.com>
Subject: [PATCH 4.9 091/109] dma-buf/sw-sync: Reduce irqsave/irqrestore from known context

4.9-stable review patch.  If anyone has any objections, please let me know.

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

From: Chris Wilson <chris@...is-wilson.co.uk>

commit a6aa8fca4d792c72947e341d7842d2f700534335 upstream.

If we know the context under which we are called, then we can use the
simpler form of spin_lock_irq (saving the save/restore).

Signed-off-by: Chris Wilson <chris@...is-wilson.co.uk>
Cc: Sumit Semwal <sumit.semwal@...aro.org>
Cc: Sean Paul <seanpaul@...omium.org>
Cc: Gustavo Padovan <gustavo@...ovan.org>
Reviewed-by: Sean Paul <seanpaul@...omium.org>
Signed-off-by: Gustavo Padovan <gustavo.padovan@...labora.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170629125930.821-4-chris@chris-wilson.co.uk
[s/dma_fence/fence/g - gregkh]
Cc: Jisheng Zhang <Jisheng.Zhang@...aptics.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/dma-buf/sw_sync.c    |   15 +++++++++------
 drivers/dma-buf/sync_debug.c |   14 ++++++--------
 2 files changed, 15 insertions(+), 14 deletions(-)

--- a/drivers/dma-buf/sw_sync.c
+++ b/drivers/dma-buf/sw_sync.c
@@ -135,12 +135,11 @@ static void sync_timeline_put(struct syn
  */
 static void sync_timeline_signal(struct sync_timeline *obj, unsigned int inc)
 {
-	unsigned long flags;
 	struct sync_pt *pt, *next;
 
 	trace_sync_timeline(obj);
 
-	spin_lock_irqsave(&obj->child_list_lock, flags);
+	spin_lock_irq(&obj->child_list_lock);
 
 	obj->value += inc;
 
@@ -150,7 +149,7 @@ static void sync_timeline_signal(struct
 			list_del_init(&pt->active_list);
 	}
 
-	spin_unlock_irqrestore(&obj->child_list_lock, flags);
+	spin_unlock_irq(&obj->child_list_lock);
 }
 
 /**
@@ -167,7 +166,6 @@ static void sync_timeline_signal(struct
 static struct sync_pt *sync_pt_create(struct sync_timeline *obj, int size,
 			     unsigned int value)
 {
-	unsigned long flags;
 	struct sync_pt *pt;
 
 	if (size < sizeof(*pt))
@@ -177,13 +175,16 @@ static struct sync_pt *sync_pt_create(st
 	if (!pt)
 		return NULL;
 
-	spin_lock_irqsave(&obj->child_list_lock, flags);
+	spin_lock_irq(&obj->child_list_lock);
+
 	sync_timeline_get(obj);
 	fence_init(&pt->base, &timeline_fence_ops, &obj->child_list_lock,
 		   obj->context, value);
 	list_add_tail(&pt->child_list, &obj->child_list_head);
 	INIT_LIST_HEAD(&pt->active_list);
-	spin_unlock_irqrestore(&obj->child_list_lock, flags);
+
+	spin_unlock_irq(&obj->child_list_lock);
+
 	return pt;
 }
 
@@ -206,9 +207,11 @@ static void timeline_fence_release(struc
 	unsigned long flags;
 
 	spin_lock_irqsave(fence->lock, flags);
+
 	list_del(&pt->child_list);
 	if (!list_empty(&pt->active_list))
 		list_del(&pt->active_list);
+
 	spin_unlock_irqrestore(fence->lock, flags);
 
 	sync_timeline_put(parent);
--- a/drivers/dma-buf/sync_debug.c
+++ b/drivers/dma-buf/sync_debug.c
@@ -116,17 +116,16 @@ static void sync_print_fence(struct seq_
 static void sync_print_obj(struct seq_file *s, struct sync_timeline *obj)
 {
 	struct list_head *pos;
-	unsigned long flags;
 
 	seq_printf(s, "%s: %d\n", obj->name, obj->value);
 
-	spin_lock_irqsave(&obj->child_list_lock, flags);
+	spin_lock_irq(&obj->child_list_lock);
 	list_for_each(pos, &obj->child_list_head) {
 		struct sync_pt *pt =
 			container_of(pos, struct sync_pt, child_list);
 		sync_print_fence(s, &pt->base, false);
 	}
-	spin_unlock_irqrestore(&obj->child_list_lock, flags);
+	spin_unlock_irq(&obj->child_list_lock);
 }
 
 static void sync_print_sync_file(struct seq_file *s,
@@ -149,12 +148,11 @@ static void sync_print_sync_file(struct
 
 static int sync_debugfs_show(struct seq_file *s, void *unused)
 {
-	unsigned long flags;
 	struct list_head *pos;
 
 	seq_puts(s, "objs:\n--------------\n");
 
-	spin_lock_irqsave(&sync_timeline_list_lock, flags);
+	spin_lock_irq(&sync_timeline_list_lock);
 	list_for_each(pos, &sync_timeline_list_head) {
 		struct sync_timeline *obj =
 			container_of(pos, struct sync_timeline,
@@ -163,11 +161,11 @@ static int sync_debugfs_show(struct seq_
 		sync_print_obj(s, obj);
 		seq_puts(s, "\n");
 	}
-	spin_unlock_irqrestore(&sync_timeline_list_lock, flags);
+	spin_unlock_irq(&sync_timeline_list_lock);
 
 	seq_puts(s, "fences:\n--------------\n");
 
-	spin_lock_irqsave(&sync_file_list_lock, flags);
+	spin_lock_irq(&sync_file_list_lock);
 	list_for_each(pos, &sync_file_list_head) {
 		struct sync_file *sync_file =
 			container_of(pos, struct sync_file, sync_file_list);
@@ -175,7 +173,7 @@ static int sync_debugfs_show(struct seq_
 		sync_print_sync_file(s, sync_file);
 		seq_puts(s, "\n");
 	}
-	spin_unlock_irqrestore(&sync_file_list_lock, flags);
+	spin_unlock_irq(&sync_file_list_lock);
 	return 0;
 }