Patch "ARC: Elide redundant setup of DMA callbacks" has been added to the 4.4-stable tree

Patch "ARC: Elide redundant setup of DMA callbacks" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    ARC: Elide redundant setup of DMA callbacks

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     arc-elide-redundant-setup-of-dma-callbacks.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 45c3b08a117e2232fc8d7b9e849ead36386f4f96 Mon Sep 17 00:00:00 2001
From: Vineet Gupta <vgupta@synopsys.com>
Date: Mon, 13 Jun 2016 16:38:27 +0200
Subject: ARC: Elide redundant setup of DMA callbacks

From: Vineet Gupta <vgupta@synopsys.com>

commit 45c3b08a117e2232fc8d7b9e849ead36386f4f96 upstream.

For resources shared by all cores such as SLC and IOC, only the master
core needs to do any setups / enabling / disabling etc.

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/arc/mm/cache.c |    9 +++++++++
 1 file changed, 9 insertions(+)

--- a/arch/arc/mm/cache.c
+++ b/arch/arc/mm/cache.c
@@ -914,6 +914,15 @@ void arc_cache_init(void)
 
 	printk(arc_cache_mumbojumbo(0, str, sizeof(str)));
 
+	/*
+	 * Only master CPU needs to execute rest of function:
+	 *  - Assume SMP so all cores will have same cache config so
+	 *    any geomtry checks will be same for all
+	 *  - IOC setup / dma callbacks only need to be setup once
+	 */
+	if (cpu)
+		return;
+
 	if (IS_ENABLED(CONFIG_ARC_HAS_ICACHE)) {
 		struct cpuinfo_arc_cache *ic = &cpuinfo_arc700[cpu].icache;
 


Patches currently in stable-queue which might be from vgupta@synopsys.com are

queue-4.4/arc-build-better-way-to-detect-isa-compatible-toolchain.patch
queue-4.4/arc-elide-redundant-setup-of-dma-callbacks.patch
queue-4.4/arc-call-trace_hardirqs_on-before-enabling-irqs.patch
queue-4.4/arc-use-correct-offset-in-pt_regs-for-saving-restoring-user-mode-r25.patch