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Nathan Lynch authored
The protocol for suspending or migrating an LPAR requires all present processor threads to enter H_JOIN. So if we have threads offline, we have to temporarily bring them up. This can race with administrator actions such as SMT state changes. As of dfd718a2 ("powerpc/rtas: Fix a potential race between CPU-Offline & Migration"), rtas_ibm_suspend_me() accounts for this, but errors out with -EBUSY for what almost certainly is a transient condition in any reasonable scenario. Callers of rtas_ibm_suspend_me() already retry when -EAGAIN is returned, and it is typical during a migration for that to happen repeatedly for several minutes polling the H_VASI_STATE hcall result before proceeding to the next stage. So return -EAGAIN instead of -EBUSY when this race is encountered. Additionally: logging this event is still appropriate but use pr_info instead of pr_err; and remove use of unlikely() while here as this is not a hot path at all. Fixes: dfd718a2 ("powerpc/rtas: Fix a potential race between CPU-Offline & Migration") Signed-off-by:
Nathan Lynch <nathanl@linux.ibm.com> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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