On 6/7/07, Satyam Sharma <[EMAIL PROTECTED]> wrote:
[...] BTW: smp_call_function() simply returns 0 and smp_call_function_single() simply returns -EBUSY when !SMP. These appear to be just some ad hoc values. IMHO, we should be going BUG() in both these cases because "other" CPUs for !SMP are undefined / meaningless.
79974a0e4c6be6e9a3717b4c5a5d5c44c36b1653 from a couple weeks back (discussed on http://lkml.org/lkml/2007/5/14/68 i.e. [patch] Let smp_call_function_single return -EBUSY.) introduced this behaviour. [ Adding Heiko Carstens, Andrew and David Miller to Cc: list. ] I realized a warning would be more appropriate for this case than a BUG at the last moment ... this doesn't quite meet Linus' "You killed my father; prepare to die!" criterion :-) --- The smp_call_function{_single} functions are used to run given function on all {or speicified} *other* CPUs. For UP systems, "other" CPUs simply don't exist, so we flag such incorrect usage of these functions using a WARNING. Also, -EBUSY is generally returned by arch implementations when they find that target_cpu == current_cpu, which is not a comparable case to the !SMP case. Use -EINVAL instead, similar to what powerpc does for !cpu_online(target), which is somewhat more analogous. Signed-off-by: Satyam Sharma <[EMAIL PROTECTED]> Cc: Ingo Molnar <[EMAIL PROTECTED]> Cc: Andi Kleen <[EMAIL PROTECTED]> Cc: Alan Cox <[EMAIL PROTECTED]> Cc: Heiko Carstens <[EMAIL PROTECTED]> Cc: Andrew Morton <[EMAIL PROTECTED]> Cc: David Miller <[EMAIL PROTECTED]> --- include/linux/smp.h | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) --- diff -ruNp a/include/linux/smp.h b/include/linux/smp.h --- a/include/linux/smp.h 2007-06-07 12:46:50.000000000 +0530 +++ b/include/linux/smp.h 2007-06-07 21:13:29.000000000 +0530 @@ -6,6 +6,7 @@ * Alan Cox. <[EMAIL PROTECTED]> */ +#include <linux/bug.h> #include <linux/errno.h> extern void cpu_idle(void); @@ -84,11 +85,6 @@ void smp_prepare_boot_cpu(void); * These macros fold the SMP functionality into a single CPU system */ #define raw_smp_processor_id() 0 -static inline int up_smp_call_function(void) -{ - return 0; -} -#define smp_call_function(func,info,retry,wait) (up_smp_call_function()) #define on_each_cpu(func,info,retry,wait) \ ({ \ local_irq_disable(); \ @@ -99,10 +95,17 @@ static inline int up_smp_call_function(v static inline void smp_send_reschedule(int cpu) { } #define num_booting_cpus() 1 #define smp_prepare_boot_cpu() do {} while (0) +static inline int smp_call_function(void (*func)(void *info), + void *info, int retry, int wait) +{ + WARN_ON(1); + return -EINVAL; +} static inline int smp_call_function_single(int cpuid, void (*func) (void *info), void *info, int retry, int wait) { - return -EBUSY; + WARN_ON(1); + return -EINVAL; } #endif /* !SMP */ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
