On Thu, 2017-12-07 at 12:02 +0000, John Garry wrote: > On 07/12/2017 01:55, Martin K. Petersen wrote: > > > > Bart, > > > > > As reported by Pavel Tikhomirov it can happen that the SCSI error > > > handler does not get woken up. This is very annoying because it > > > results in a queue stall. The two patches in this series address this > > > issue without acquiring the SCSI host lock in the hot path. Please > > > consider these patches for kernel v4.16. > > > > Applied to 4.16/scsi-queue. Thank you! > > > > Is anyone finding a build error for this patch? I built allmodconfig on > Martin's 4.16/scsi-queue and I get this: > ERROR: "init_rcu_head" [drivers/scsi/scsi_mod.ko] undefined! > ERROR: "destroy_rcu_head" [drivers/scsi/scsi_mod.ko] undefined! > > Reverting fixes it. > > From a quick check, it seems the rcu funcitons are not exported, and > SCSI=m means hosts.c cannot reference it. Hello John, A discussion is ongoing about this issue on the linux-next mailing list. Paul E. McKenney proposed to export both the init_rcu_head() and destroy_rcu_head() functions. See also https://lkml.org/lkml/2017/12/6/1150. Bart.
