On Fri, Aug 20, 2021 at 5:31 PM Song Liu <song@xxxxxxxxxx> wrote:
>
> On Tue, Aug 17, 2021 at 10:58 PM Xiao Ni <xni@xxxxxxxxxx> wrote:
> >
> > One warning message is triggered like this:
> > [ 695.110751] =============================
> > [ 695.131439] WARNING: suspicious RCU usage
> > [ 695.151389] 4.18.0-319.el8.x86_64+debug #1 Not tainted
> > [ 695.174413] -----------------------------
> > [ 695.192603] drivers/md/raid10.c:1776 suspicious
> > rcu_dereference_check() usage!
> > [ 695.225107] other info that might help us debug this:
> > [ 695.260940] rcu_scheduler_active = 2, debug_locks = 1
> > [ 695.290157] no locks held by mkfs.xfs/10186.
> >
> > In the first loop of function raid10_handle_discard. It already
> > determines which disk need to handle discard request and add the
> > rdev reference count rdev->nr_pending. So the conf->mirrors will
> > not change until all bios come back from underlayer disks. It
> > doesn't need to use rcu_dereference to get rdev.
> >
> > Fixes: d30588b2731f ('md/raid10: improve raid10 discard request')
> > Signed-off-by: Xiao Ni <xni@xxxxxxxxxx>
> > Acked-by: Guoqing Jiang <guoqing.jiang@xxxxxxxxx>
>
> Applied to md-fixes. Thanks!
Moved to md-next as we are too close to 5.14 release.
Thanks,
Song
