powerpc/fadump: re-register firmware-assisted dump if already registered
authorHari Bathini <hbathini@linux.ibm.com>
Fri, 14 Sep 2018 14:06:02 +0000 (19:36 +0530)
committerMichael Ellerman <mpe@ellerman.id.au>
Wed, 19 Sep 2018 12:08:12 +0000 (22:08 +1000)
commit0823c68b054bca9dc321adea829af5cf36afb30b
treebe5af0713d0289ed80e18df711ad34fb1786bc8b
parent74422e2b19391e0bb9f11b0ab4522bbf7f93c4ba
powerpc/fadump: re-register firmware-assisted dump if already registered

Firmware-Assisted Dump (FADump) needs to be registered again after any
memory hot add/remove operation to update the crash memory ranges. But
currently, the kernel returns '-EEXIST' if we try to register without
uregistering it first. This could expose the system to racing issues
while unregistering and registering FADump from userspace during udev
events. Spare the userspace of this and let it be taken care of in the
kernel space for a simpler interface.

Since this change, running 'echo 1 > /sys/kernel/fadump_registered'
would result in re-regisering (unregistering and registering) FADump,
if it was already registered.

Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Acked-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
arch/powerpc/kernel/fadump.c