Patch preempt and win4lin

Hi all,

I am maintaining the Debian package containing the preemptible kernel from Robert Love.

A user told me that win4lin stops working when the preemptible patch is used. He sent me a patch (see below); I have tested it on my computer it seems to work, however I don't understand exactly what it does.

Could anybody can give me some comments on this patch and the possible consequences it could generate?

Thanks
Aurelien

##
# This patch will apply to a 2.4.18 tree that has been patched with

# preempt-kernel-rml-2.4.18-5.patch
#
--- linux-2.4.18-orig/arch/i386/kernel/entry.S  Mon Feb 25 12:37:53 2002
++++ linux-2.4.18/arch/i386/kernel/entry.S       Wed Feb 27 07:16:58
2002
@@ -293,9 +293,8 @@
        jnz restore_all
        cmpl $0,need_resched(%ebx)
        jz restore_all
-       movl SYMBOL_NAME(irq_stat)+irq_stat_local_bh_count CPU_INDX,%ecx
-       addl SYMBOL_NAME(irq_stat)+irq_stat_local_irq_count
        CPU_INDX,%ecx
-       jnz restore_all
+       testl $IF_MASK,EFLAGS(%esp)     # Ints off (execption path) ?
+       jz restore_all
        incl preempt_count(%ebx)
        sti
        call SYMBOL_NAME(preempt_schedule)

You might want to check with Marc-Christian @WOLK, since he said he already got a patch awile back from the win4lin people to fix this.

Cheers,
Nicholas