genirq: Free irq_desc with rcu

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The new VMD device driver needs to iterate over a list of
"demultiplexing" interrupts. Protecting that list with a lock is not
possible because the list is also required in code pathes which hold
irq descriptor lock. Therefor the demultiplexing interrupt handler
would create a lock inversion scenario if it calls a demux handler
with the list protection lock held.

A solution for this is to free the irq descriptor via RCU, so the
list can be walked with rcu read lock held.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Keith Busch <keith.busch@intel.com>

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This commit is contained in:

Thomas Gleixner 2015-12-13 18:02:22 +01:00

parent f0cb322073

commit 425a5072dc

2 changed files with 22 additions and 3 deletions

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6

include/linux/irqdesc.h

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19

kernel/irq/irqdesc.c

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