Re: [PATCH RFC V3 6/9] x86/entry: Pass irqentry_state_t by reference

[Thomas Gleixner <tglx@linutronix.de>]

On Mon, Oct 19 2020 at 13:26, Ira Weiny wrote:
> On Mon, Oct 19, 2020 at 11:32:50AM +0200, Thomas Gleixner wrote:
> Sorry, let me clarify.  After this patch we have.
>
> typedef union irqentry_state {
> 	bool	exit_rcu;
> 	bool	lockdep;
> } irqentry_state_t;
>
> Which reflects the mutual exclusion of the 2 variables.

Huch? From the patch I gave you:

 #ifndef irqentry_state
 typedef struct irqentry_state {
 	bool    exit_rcu;
+       bool    lockdep;
 } irqentry_state_t;
 #endif

How is that a union?

> But then when the pkrs stuff is added the union changes back to a structure and
> looks like this.

So you want:

  1) Move stuff to struct irqentry_state (my patch)

  2) Change it to a union and pass it as pointer at the same time

  3) Change it back to struct to add PKRS

> Is that clear?

What's clear is that the above is nonsense. We can just do

 #ifndef irqentry_state
 typedef struct irqentry_state {
 	union {
         	bool    exit_rcu;
                bool    lockdep;
        };        
 } irqentry_state_t;
 #endif

right in the patch which I gave you. Because that actually makes sense.

Thanks,

        tglx