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[PATCH 4.2 049/134] powerpc/eeh: Probe after unbalanced kref check

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

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

From: Daniel Axtens <dja@axtens.net>

commit e642d11bdbfe8eb10116ab3959a2b5d75efda832 upstream.

In the complete hotplug case, EEH PEs are supposed to be released
and set to NULL. Normally, this is done by eeh_remove_device(),
which is called from pcibios_release_device().

However, if something is holding a kref to the device, it will not
be released, and the PE will remain. eeh_add_device_late() has
a check for this which will explictly destroy the PE in this case.

This check in eeh_add_device_late() occurs after a call to
eeh_ops->probe(). On PowerNV, probe is a pointer to pnv_eeh_probe(),
which will exit without probing if there is an existing PE.

This means that on PowerNV, devices with outstanding krefs will not
be rediscovered by EEH correctly after a complete hotplug. This is
affecting CXL (CAPI) devices in the field.

Put the probe after the kref check so that the PE is destroyed
and affected devices are correctly rediscovered by EEH.

Fixes: d91dafc02f42 ("powerpc/eeh: Delay probing EEH device during hotplug")
Cc: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Daniel Axtens <dja@axtens.net>
Acked-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/powerpc/kernel/eeh.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/arch/powerpc/kernel/eeh.c
+++ b/arch/powerpc/kernel/eeh.c
@@ -1116,9 +1116,6 @@ void eeh_add_device_late(struct pci_dev
 		return;
 	}
 
-	if (eeh_has_flag(EEH_PROBE_MODE_DEV))
-		eeh_ops->probe(pdn, NULL);
-
 	/*
 	 * The EEH cache might not be removed correctly because of
 	 * unbalanced kref to the device during unplug time, which
@@ -1142,6 +1139,9 @@ void eeh_add_device_late(struct pci_dev
 		dev->dev.archdata.edev = NULL;
 	}
 
+	if (eeh_has_flag(EEH_PROBE_MODE_DEV))
+		eeh_ops->probe(pdn, NULL);
+
 	edev->pdev = dev;
 	dev->dev.archdata.edev = edev;
 


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[PATCH 4.2 000/134] 4.2.2-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:20 +0200
  [PATCH 4.2 049/134] powerpc/eeh: Probe after unbalanced kref check Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:20 +0200
  [PATCH 4.2 018/134] MIPS: CPS: use 32b accesses to GCRs Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:20 +0200
  [PATCH 4.2 032/134] arm64: compat: fix vfp save/restore across signal handlers in big-endian Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:20 +0200
  [PATCH 4.2 047/134] pinctrl: at91: fix null pointer dereference Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:20 +0200
  [PATCH 4.2 006/134] nfc: st-nci: Remove data from ack_pending_q when receiving a SYNC_ACK Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:20 +0200
  [PATCH 4.2 015/134] rtlwifi: rtl8821ae: Fix an expression that is always false Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:20 +0200
  [PATCH 4.2 030/134] of/fdt: make memblock maximum physical address arch configurable Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:20 +0200
  [PATCH 4.2 035/134] arm/arm64: KVM: vgic: Check for !irqchip_in_kernel() when mapping resources Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:20 +0200
  [PATCH 4.2 050/134] powerpc/eeh: Fix fenced PHB caused by eeh_slot_error_detail() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:20 +0200
  [PATCH 4.2 007/134] nfc: st-nci: Free data with irrelevant NDLC PCB_SYNC value Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:20 +0200
  [PATCH 4.2 017/134] tg3: Fix temperature reporting Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:20 +0200
  [PATCH 4.2 053/134] powerpc: Uncomment and make enable_kernel_vsx() routine available Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:20 +0200
  [PATCH 4.2 003/134] nfc: st-nci: Fix non accurate comment for st_nci_i2c_read Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:20 +0200
  [PATCH 4.2 036/134] KVM: arm64: add workaround for Cortex-A57 erratum #852523 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:20 +0200
  [PATCH 4.2 004/134] NFC: st21nfca: fix use of uninitialized variables in error path Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:20 +0200
  [PATCH 4.2 037/134] arm64: KVM: Disable virtual timer even if the guest is not using it Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:20 +0200
  [PATCH 4.2 008/134] nfc: netlink: Add check on NFC_ATTR_VENDOR_DATA Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:20 +0200
  [PATCH 4.2 048/134] powerpc/pseries: Fix corrupted pdn list Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:20 +0200
  [PATCH 4.2 059/134] powerpc/mm: Recompute hash value after a failed update Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:20 +0200
  [PATCH 4.2 021/134] mac80211: enable assoc check for mesh interfaces Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:30 +0200
  [PATCH 4.2 029/134] arm64: flush FP/SIMD state correctly after execve() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:30 +0200
  [PATCH 4.2 019/134] MIPS: math-emu: Allow m{f,t}hc emulation on MIPS R6 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:30 +0200
  [PATCH 4.2 024/134] cxl: Fix unbalanced pci_dev_get in cxl_probe Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:30 +0200
  [PATCH 4.2 002/134] nfc: st-nci: Fix typo when changing from st21nfcb to st-nci Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:30 +0200
  [PATCH 4.2 022/134] cxl: Allow release of contexts which have been OPENED but not STARTED Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:30 +0200
  [PATCH 4.2 027/134] arm64: kconfig: Move LIST_POISON to a safe value Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:30 +0200
  [PATCH 4.2 020/134] MIPS: math-emu: Emulate missing BC1{EQ,NE}Z instructions Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:30 +0200
  [PATCH 4.2 025/134] ext4: dont manipulate recovery flag when freezing no-journal fs Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:30 +0200
  [PATCH 4.2 028/134] arm64: entry: always restore x0 from the stack on syscall return Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:30 +0200
  [PATCH 4.2 010/134] nfc: nci: hci: Add check on skb nci_hci_send_cmd parameter Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:30 +0200
  [PATCH 4.2 026/134] Revert "ext4: remove block_device_ejected" Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:30 +0200
  [PATCH 4.2 023/134] cxl: Remove racy attempt to force EEH invocation in reset Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 00:30 +0200
  Re: [PATCH 4.2 000/134] 4.2.2-stable review Guenter Roeck <linux@roeck-us.net> - 2015-09-27 20:20 +0200
    Re: [PATCH 4.2 000/134] 4.2.2-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-27 20:40 +0200
  Re: [PATCH 4.2 000/134] 4.2.2-stable review Sudip Mukherjee <sudipm.mukherjee@gmail.com> - 2015-09-28 08:00 +0200
    Re: [PATCH 4.2 000/134] 4.2.2-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-28 16:30 +0200
      Re: [PATCH 4.2 000/134] 4.2.2-stable review Sudip Mukherjee <sudipm.mukherjee@gmail.com> - 2015-09-28 17:10 +0200
      Re: [PATCH 4.2 000/134] 4.2.2-stable review Guenter Roeck <linux@roeck-us.net> - 2015-09-28 17:10 +0200
  Re: [PATCH 4.2 000/134] 4.2.2-stable review Shuah Khan <shuahkh@osg.samsung.com> - 2015-09-28 19:40 +0200

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