[PATCH] Fix a irqcount comment in entry.S

Signed-off-by: Andi Kleen <ak@suse.de>

diff --git a/arch/x86_64/kernel/entry.S b/arch/x86_64/kernel/entry.S
index 4fcc0ad8bbeb3630117375e478f143f648a97b4f..ea32688386fd85148e2d466290bd32ef69707d4d 100644 (file)
--- a/arch/x86_64/kernel/entry.S
+++ b/arch/x86_64/kernel/entry.S
@@ -519,7 +519,12 @@ END(stub_rt_sigreturn)
        testl $3,CS(%rdi)
        je 1f
        swapgs  
-1:     incl    %gs:pda_irqcount        # RED-PEN should check preempt count
+       /* irqcount is used to check if a CPU is already on an interrupt
+          stack or not. While this is essentially redundant with preempt_count
+          it is a little cheaper to use a separate counter in the PDA
+          (short of moving irq_enter into assembly, which would be too
+           much work) */
+1:     incl    %gs:pda_irqcount
        cmoveq %gs:pda_irqstackptr,%rsp
        push    %rbp                    # backlink for old unwinder
        /*