On Mon, Oct 21, 2024 at 11:51:40PM -0700, Christoph Hellwig wrote: > On Mon, Oct 21, 2024 at 03:13:05PM -0700, Paul E. McKenney wrote: > > For almost 20 years, the int return value from srcu_read_lock() has > > been always either zero or one. This commit therefore documents the > > fact that it will be non-negative. > > If it is always zero or one, wouldn't bool the better return value > type?
What is returned is an array index -- and SRCU is currently built using an array of size 2. Using larger arrays is conceivable (IIRC some versions of preemptible RCU used up to 4 or something). So while the values 0,1 are possible inside bool, that does not reflect the nature of the numbers, which is an array index. Mapping that onto bool would be slightly confusing (and limit possible future extention of using larger arrays for SRCU).
