On Tue, May 22 2018 at 2:34am -0400, Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote: > On Sat, May 19, 2018 at 07:25:05AM +0200, Mikulas Patocka wrote: > > In order to reduce locking overhead, I use the spinlock in > > swait_queue_head to protect not only the wait queue, but also the list of > > events. Consequently, I need to use unlocked functions __prepare_to_swait > > and __finish_swait. These functions are declared in the file > > include/linux/swait.h, but they are not exported, and so they are not > > useable from kernel modules. > > Please CC the author and maintainers of the swait code. > > My impression is that this is the wrong thing to do. The swait code > is supposed to be simple and self contained, and if you want to do > anything else use normal waitqueues. You said the same thing last time around. I've since cc'd Peter and Thomas and haven't heard back, see: https://www.redhat.com/archives/dm-devel/2018-May/msg00048.html The entire point of exporting these symbols is to allow use of the "simple waitqueue" code to optimize -- without resorting to using normal waitqueues. Mike -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
