powerpc/powernv: Return for invalid IMC domain [Linux 5.2]

powerpc/powernv: Return for invalid IMC domain [Linux 5.2]

This Linux kernel change "powerpc/powernv: Return for invalid IMC domain" is included in the Linux 5.2 release. This change is authored by Anju T Sudhakar <anju [at] linux.vnet.ibm.com> on Mon May 20 14:27:53 2019 +0530. The commit for this change in Linux stable tree is b59bd35 (patch).

powerpc/powernv: Return for invalid IMC domain

Currently init_imc_pmu() can fail either because we try to register an
IMC unit with an invalid domain (i.e an IMC node not supported by the
kernel) or something went wrong while registering a valid IMC unit. In
both the cases kernel provides a 'Register failed' error message.

For example when trace-imc node is not supported by the kernel, but
skiboot advertises a trace-imc node we print:

  IMC Unknown Device type
  IMC PMU (null) Register failed

To avoid confusion just print the unknown device type message, before
attempting PMU registration, so the second message isn't printed.

Fixes: 8f95faaac56c ("powerpc/powernv: Detect and create IMC device")
Reported-by: Pavaman Subramaniyam <pavsubra@in.ibm.com>
Signed-off-by: Anju T Sudhakar <anju@linux.vnet.ibm.com>
Reviewed-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
[mpe: Reword change log a bit]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

There are 4 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.

 arch/powerpc/platforms/powernv/opal-imc.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/powerpc/platforms/powernv/opal-imc.c b/arch/powerpc/platforms/powernv/opal-imc.c
index 3e497b9..52e9e15 100644
--- a/arch/powerpc/platforms/powernv/opal-imc.c
+++ b/arch/powerpc/platforms/powernv/opal-imc.c
@@ -161,6 +161,10 @@ static int imc_pmu_create(struct device_node *parent, int pmu_index, int domain)
    struct imc_pmu *pmu_ptr;
    u32 offset;

+   /* Return for unknown domain */
+   if (domain < 0)
+       return -EINVAL;
    /* memory for pmu */
    pmu_ptr = kzalloc(sizeof(*pmu_ptr), GFP_KERNEL);
    if (!pmu_ptr)

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