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authorNathan Lynch <nathanl@linux.ibm.com>2020-12-08 00:51:35 +0300
committerMichael Ellerman <mpe@ellerman.id.au>2020-12-08 13:40:54 +0300
commit7049b288ea8c95f270ec8fe643e3c3187938d5af (patch)
tree1198b3b4d30b439342b521dd4a657245251b844f /arch/powerpc/platforms/pseries/mobility.c
parent970e453ea4ecdd7a16a46c229294547148d1c7b6 (diff)
downloadlinux-7049b288ea8c95f270ec8fe643e3c3187938d5af.tar.xz
powerpc/rtas: rtas_ibm_suspend_me -> rtas_ibm_suspend_me_unsafe
The pseries partition suspend sequence requires that all active CPUs call H_JOIN, which suspends all but one of them with interrupts disabled. The "chosen" CPU is then to call ibm,suspend-me to complete the suspend. Upon returning from ibm,suspend-me, the chosen CPU is to use H_PROD to wake the joined CPUs. Using on_each_cpu() for this, as rtas_ibm_suspend_me() does to implement partition migration, is susceptible to deadlock with other users of on_each_cpu() and with users of stop_machine APIs. The callback passed to on_each_cpu() is not allowed to synchronize with other CPUs in the way it is used here. Complicating the fix is the fact that rtas_ibm_suspend_me() also occupies the function name that should be used to provide a more conventional wrapper for ibm,suspend-me. Rename rtas_ibm_suspend_me() to rtas_ibm_suspend_me_unsafe() to free up the name and indicate that it should not gain users. Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20201207215200.1785968-4-nathanl@linux.ibm.com
Diffstat (limited to 'arch/powerpc/platforms/pseries/mobility.c')
-rw-r--r--arch/powerpc/platforms/pseries/mobility.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c
index 2f73cb5bf12d..6ff642e84c6a 100644
--- a/arch/powerpc/platforms/pseries/mobility.c
+++ b/arch/powerpc/platforms/pseries/mobility.c
@@ -370,7 +370,7 @@ static ssize_t migration_store(struct class *class,
return rc;
do {
- rc = rtas_ibm_suspend_me(streamid);
+ rc = rtas_ibm_suspend_me_unsafe(streamid);
if (rc == -EAGAIN)
ssleep(1);
} while (rc == -EAGAIN);