41d2d848e5c0 ("md: improve io stats accounting") was added during the 5.9 cycle and therefore is present in the 5.10 branch. This patch was then reverted in mainline during the 5.14 cycle (ad3fc798800f) due to report of double faults [1]. However the revert was not picked up for the 5.10 branch. I believe it should be queued up. Unfortunately, 41d2d848e5c0 in 5.10 cannot be reverted cleanly because of the later changes in 00fe60eae94. The mainline 5.14 revert commit also does not apply cleanly on 5.10 because 99dfc43ecbf6 is not in 5.10. Manually merging the revert is trivial though (I could provide the patch I've been testing if that's helpful). Guillaume. [1]. https://lore.kernel.org/linux-raid/3bf04253-3fad-434a-63a7-20214e38cf26@xxxxxxxxx/T/#t -- Guillaume Morin <guillaume@xxxxxxxxxxx>