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authorWill Deacon2017-12-01 15:29:39 +0000
committerThomas Gleixner2017-12-04 20:51:12 +0100
commit4ce413d1840b25b101be3c0559161db8891f3360 (patch)
tree969656d510deb1d314d44055b2daf840ba0cf9f7 /kernel
parentbb5c43428252f27b875c764451321a83a531d6e5 (diff)
irqdesc: Use bool return type instead of int
The irq_balancing_disabled and irq_is_percpu{,_devid} functions are clearly intended to return bool like the functions in kernel/irq/settings.h, but actually return an int containing a masked value of desc->status_use_accessors. This can lead to subtle breakage if, for example, the return value is subsequently truncated when assigned to a narrower type. As Linus points out: | In particular, what can (and _has_ happened) is that people end up | using these functions that return true or false, and they assign the | result to something like a bitfield (or a char) or whatever. | | And the code looks *obviously* correct, when you have things like | | dev->percpu = irq_is_percpu_devid(dev->irq); | | and that "percpu" thing is just one status bit among many. It may even | *work*, because maybe that "percpu" flag ends up not being all that | important, or it just happens to never be set on the particular | hardware that people end up testing. | | But while it looks obviously correct, and might even work, it's really | fundamentally broken. Because that "true or false" function didn't | actually return 0/1, it returned 0 or 0x20000. | | And 0x20000 may not fit in a bitmask or a "char" or whatever. Fix the problem by consistently using bool as the return type for these functions. Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: marc.zyngier@arm.com Link: https://lkml.kernel.org/r/1512142179-24616-1-git-send-email-will.deacon@arm.com
Diffstat (limited to 'kernel')
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