On Tue, Jan 30, 2024 at 12:14:32PM +0000, John Garry wrote: > On 28/01/2024 16:58, Christoph Hellwig wrote: >> Convert queue_max_sectors_store to use queue_limits_commit_update to >> check and update the max_sectors limit and freeze the queue before >> doing so to ensure we don't have requests in flight while changing >> the limits. >> >> Note that this removes the previously held queue_lock that doesn't >> protect against any other reader or writer. > > I don't really get why we specifically locked that code segment in > queue_max_sectors_store() previously. Was it to ensure max_sectors and > q->disk->bdi->io_pages are always atomically updated? It's been there basically forever. Back in the day before blk-mq and lock splitting it might actually have protected something.
