Patch "MIPS: CM: Drop WARN_ON(vp != 0)" has been added to the 4.14-stable tree

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

    MIPS: CM: Drop WARN_ON(vp != 0)

to the 4.14-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:

     mips-cm-drop-warn_on-vp-0.patch

and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: James Hogan <[email protected]>
Date: Tue, 5 Dec 2017 22:28:22 +0000
Subject: MIPS: CM: Drop WARN_ON(vp != 0)

From: James Hogan <[email protected]>

commit c04de7b1ad645b61c141df8ca903ba0cc03a57f7 upstream.

Since commit 68923cdc2eb3 ("MIPS: CM: Add cluster & block args to mips_cm_lock_other()"), mips_smp_send_ipi_mask() has used mips_cm_lock_other_cpu() with each CPU number, rather than mips_cm_lock_other() with the first VPE in each core. Prior to r6, multicore multithreaded systems such as dual-core dual-thread interAptivs with CPU Idle enabled (e.g. MIPS Creator Ci40) results in mips_cm_lock_other() repeatedly hitting WARN_ON(vp != 0).

There doesn't appear to be anything fundamentally wrong about passing a non-zero VP/VPE number, even if it is a core's region that is locked into the other region before r6, so remove that particular WARN_ON().

Patchwork: https://patchwork.linux-mips.org/patch/17883/

---
 arch/mips/kernel/mips-cm.c |    1 -
 1 file changed, 1 deletion(-)

@@ -292,7 +292,6 @@ void mips_cm_lock_other(unsigned int clu
 				  *this_cpu_ptr(&cm_core_lock_flags));
 	} else {
 		WARN_ON(cluster != 0);
-		WARN_ON(vp != 0);
 		WARN_ON(block != CM_GCR_Cx_OTHER_BLOCK_LOCAL);
 
 		/*

Patches currently in stable-queue which might be from [email protected] are

queue-4.14/mips-cm-drop-warn_on-vp-0.patch