Re: [PATCH] Fix sparc TIF_USEDFPU flag atomicity

[William Lee Irwin III]

On Sat, Mar 10, 2007 at 03:17:43AM -0500, Mathieu Desnoyers wrote:
> @@ -348,7 +348,7 @@ void exit_thread(void)
>  #ifndef CONFIG_SMP
>       if(last_task_used_math == current) {
>  #else
> -     if(current_thread_info()->flags & _TIF_USEDFPU) {
> +     if(test_ti_thread_flag(current_thread_info(), TIF_USEDFPU)) {
>  #endif
>               /* Keep process from leaving FPU in a bogon state. */
>               put_psr(get_psr() | PSR_EF);

Oh dear. Could we bit a bit more idiomatic here? For instance,
something like:

Index: linux-2.6/arch/sparc/kernel/process.c
===================================================================
--- linux-2.6.orig/arch/sparc/kernel/process.c  2007-03-09 23:24:12.934472032 
-0800
+++ linux-2.6/arch/sparc/kernel/process.c       2007-03-09 23:29:26.592346376 
-0800
@@ -348,7 +348,7 @@
 #ifndef CONFIG_SMP
        if(last_task_used_math == current) {
 #else
-       if(current_thread_info()->flags & _TIF_USEDFPU) {
+       if (test_thread_flag(TIF_USEDFPU)) {
 #endif
                /* Keep process from leaving FPU in a bogon state. */
                put_psr(get_psr() | PSR_EF);
@@ -357,7 +357,7 @@
 #ifndef CONFIG_SMP
                last_task_used_math = NULL;
 #else
-               current_thread_info()->flags &= ~_TIF_USEDFPU;
+               clear_thread_flag(TIF_USEDFPU);
 #endif
        }
 }
@@ -371,7 +371,7 @@
 #ifndef CONFIG_SMP
        if(last_task_used_math == current) {
 #else
-       if(current_thread_info()->flags & _TIF_USEDFPU) {
+       if (test_thread_flag(TIF_USEDFPU)) {
 #endif
                /* Clean the fpu. */
                put_psr(get_psr() | PSR_EF);
@@ -380,7 +380,7 @@
 #ifndef CONFIG_SMP
                last_task_used_math = NULL;
 #else
-               current_thread_info()->flags &= ~_TIF_USEDFPU;
+               clear_thread_flag(TIF_USEDFPU);
 #endif
        }
 
@@ -466,13 +466,13 @@
 #ifndef CONFIG_SMP
        if(last_task_used_math == current) {
 #else
-       if(current_thread_info()->flags & _TIF_USEDFPU) {
+       if (test_thread_flag(TIF_USEDFPU)) {
 #endif
                put_psr(get_psr() | PSR_EF);
                fpsave(&p->thread.float_regs[0], &p->thread.fsr,
                       &p->thread.fpqueue[0], &p->thread.fpqdepth);
 #ifdef CONFIG_SMP
-               current_thread_info()->flags &= ~_TIF_USEDFPU;
+               clear_thread_flag(TIF_USEDFPU);
 #endif
        }
 
@@ -609,13 +609,13 @@
                return 1;
        }
 #ifdef CONFIG_SMP
-       if (current_thread_info()->flags & _TIF_USEDFPU) {
+       if (test_thread_flag(TIF_USEDFPU)) {
                put_psr(get_psr() | PSR_EF);
                fpsave(&current->thread.float_regs[0], &current->thread.fsr,
                       &current->thread.fpqueue[0], &current->thread.fpqdepth);
                if (regs != NULL) {
                        regs->psr &= ~(PSR_EF);
-                       current_thread_info()->flags &= ~(_TIF_USEDFPU);
+                       clear_thread_flag(TIF_USEDFPU);
                }
        }
 #else
Index: linux-2.6/arch/sparc/kernel/traps.c
===================================================================
--- linux-2.6.orig/arch/sparc/kernel/traps.c    2007-03-09 23:40:33.994379450 
-0800
+++ linux-2.6/arch/sparc/kernel/traps.c 2007-03-09 23:44:07.910569839 -0800
@@ -259,7 +259,7 @@
        } else {
                fpload(&current->thread.float_regs[0], &current->thread.fsr);
        }
-       current_thread_info()->flags |= _TIF_USEDFPU;
+       set_thread_flag(TIF_USEDFPU);
 #endif
 }
 
@@ -290,7 +290,7 @@
 #ifndef CONFIG_SMP
        if(!fpt) {
 #else
-        if(!(task_thread_info(fpt)->flags & _TIF_USEDFPU)) {
+       if (!test_tsk_thread_flag(fpt, TIF_USEDFPU)) {
 #endif
                fpsave(&fake_regs[0], &fake_fsr, &fake_queue[0], &fake_depth);
                regs->psr &= ~PSR_EF;
@@ -333,7 +333,7 @@
        /* nope, better SIGFPE the offending process... */
               
 #ifdef CONFIG_SMP
-       task_thread_info(fpt)->flags &= ~_TIF_USEDFPU;
+       clear_tsk_thread_flag(fpt, TIF_USEDFPU);
 #endif
        if(psr & PSR_PS) {
                /* The first fsr store/load we tried trapped,
-
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