On 12/23, Jason Seba wrote:
>
> Wouldn't the contents of the global flags value be protected by the
> spinlock itself?
This can be even true because nowadays spin_lock_irqsave() writes to
"flags" after it takes the lock, and _irqrestore works gets the copy
of "flags" before it releases the lock.
Still this doesn't look safe and afaik this is not documented. Although
I have to admit that after I actually looked at the current implementation
I think this should work.
Perhaps we should ask the maintainers upstream? Even if this works, I am
not sure this is _supposed_ to work. I mean, in theory spin_lock_irqave()
can be changed as, say
#define spin_lock_irqsave(lock, flags) \
do { \
local_irq_save(flags); \
spin_lock(lock); \
} while (0)
(and iirc it was defined this way a long ago). In this case "flags" is
obviously not protected.
Oleg.
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