On Mon, Mar 15, 2021 at 04:25:32PM +0800, Qu Wenruo wrote: > > > On 2021/3/15 下午3:55, Johannes Thumshirn wrote: > > On 15/03/2021 06:40, Qu Wenruo wrote: > >> The difference against find_extent_buffer_nospinlock() is: > >> - Also handles regular sectorsize == PAGE_SIZE case > >> - No extent buffer refs increase/decrease > >> As extent buffer under IO must has non-zero refs. > > > > Can these be merged into a single function? The sectorsie == PAGE_SIZE case > > won't do anything for find_extent_buffer_nospinlock() and the > > atomic_inc_not_zero(&eb->refs) can be hidden behind a 'if (write)' check. > > That would make the eb refs change too inconsistent. > > But I get your point. > > How about calling find_extent_buffer_nospinlock() and then dec the refs > manually?
Is this equivalent to this patch? Ie. the atomic_inc_not_zero in find_extent_buffer_nospinlock happens inside the RCU section, while what you suggest looks like find_extent_buffer_nospinlock() rcu_lock radix_lookup rcu_unlock atomic_inc_not_zero()
