From 8d613e0e81561ce0b1d6ea834b07c73f5f9251a1 Mon Sep 17 00:00:00 2001 From: Michal Suchanek Date: Fri, 9 Feb 2024 13:12:33 +0100 Subject: [PATCH] ppc64_cpu: Clean up sysfs smt/control error handling When the kernel does not support the sysfs intercface do not report an arror, fall back to the old method silently. Suggested-by: Nathan Lynch Signed-off-by: Michal Suchanek --- v3: retry is needed on ENODEV to support powernv --- src/ppc64_cpu.c | 24 +++++++++++++++++++----- 1 file changed, 19 insertions(+), 5 deletions(-) diff --git a/src/ppc64_cpu.c b/src/ppc64_cpu.c index c318928..688152b 100644 --- a/src/ppc64_cpu.c +++ b/src/ppc64_cpu.c @@ -364,14 +364,28 @@ static int is_dscr_capable(void) /* * Depends on kernel's CONFIG_HOTPLUG_CPU + * Return -1 for fatal error, -2 to retry. */ static int set_smt_control(int smt_state) { if (set_attribute(SYS_SMT_CONTROL, "%d", smt_state)) { - /* Silently ignore kernel not supporting this feature */ - if (errno != ENODEV) - perror(SYS_SMT_CONTROL); - return -1; + switch (errno) { + case ENOENT: + /* + * The kernel does not have the interface. + * Try the old method. + */ + return -2; + case ENODEV: + /* + * Setting SMT state not supported by this interface. + * eg. powernv + */ + return -2; + default: + perror(SYS_SMT_CONTROL); + return -1; + } } return 0; } @@ -405,7 +419,7 @@ static int do_smt(char *state, bool numeric) } /* Try using smt/control if failing, fall back to the legacy way */ - if (set_smt_control(smt_state)) + if ((rc = set_smt_control(smt_state)) == -2) rc = set_smt_state(smt_state); } -- 2.44.0