linux-kernel - [PATCH 20/25] x86/mcheck: Be prepared for a rollback back to the ONLINE state

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Date:   Thu,  3 Nov 2016 15:50:16 +0100
From:   Sebastian Andrzej Siewior <bigeasy@...utronix.de>
To:     linux-kernel@...r.kernel.org
Cc:     rt@...utronix.de,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        Tony Luck <tony.luck@...el.com>,
        Borislav Petkov <bp@...en8.de>, linux-edac@...r.kernel.org,
        x86@...nel.org, Thomas Gleixner <tglx@...utronix.de>
Subject: [PATCH 20/25] x86/mcheck: Be prepared for a rollback back to the ONLINE state

If we try a CPU down and fail in the middle then we roll back to the
online state. This  means we would perform CPU_ONLINE()
without invoking CPU_DEAD() for the cleanup of what was allocated in
CPU_ONLINE.
Be prepared for this and don't allocate the struct if we have it
already.

Cc: Tony Luck <tony.luck@...el.com>
Cc: Borislav Petkov <bp@...en8.de>
Cc: linux-edac@...r.kernel.org
Cc: x86@...nel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
---
 arch/x86/kernel/cpu/mcheck/mce.c     | 4 ++++
 arch/x86/kernel/cpu/mcheck/mce_amd.c | 3 +++
 2 files changed, 7 insertions(+)

diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index a7fdf453d895..e9ffd6d9e32d 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -2409,6 +2409,10 @@ static int mce_device_create(unsigned int cpu)
 	if (!mce_available(&boot_cpu_data))
 		return -EIO;
 
+	dev = per_cpu(mce_device, cpu);
+	if (dev)
+		return 0;
+
 	dev = kzalloc(sizeof *dev, GFP_KERNEL);
 	if (!dev)
 		return -ENOMEM;
diff --git a/arch/x86/kernel/cpu/mcheck/mce_amd.c b/arch/x86/kernel/cpu/mcheck/mce_amd.c
index 55cd018bc1ae..3e529fd747f8 100644
--- a/arch/x86/kernel/cpu/mcheck/mce_amd.c
+++ b/arch/x86/kernel/cpu/mcheck/mce_amd.c
@@ -1097,6 +1097,9 @@ static int threshold_create_device(unsigned int cpu)
 	struct threshold_bank **bp;
 	int err = 0;
 
+	bp = per_cpu(threshold_banks, cpu);
+	if (bp)
+		return 0;
 	bp = kzalloc(sizeof(struct threshold_bank *) * mca_cfg.banks,
 		     GFP_KERNEL);
 	if (!bp)
-- 
2.10.2