The patch titled iova: lockdep false alarm fix has been added to the -mm tree. Its filename is iova-lockdep-false-alarm-fix.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: iova: lockdep false alarm fix From: mark gross <mgross@xxxxxxxxxxxxxxx> lockdep goes off on the iova copy_reserved_iova() because it and a function it calls grabs locks in the from, and the to of the copy operation. The function grab locks of the same lock classes triggering the warning. The first lock grabbed is for the constant reserved areas that is never accessed after early boot. Technically you could do without grabbing the locks for the "from" structure its copying reserved areas from. But dropping the from locks to me looks wrong, even though it would be ok. The affected code only runs in early boot as its setting up the DMAR engines. This patch gives the reserved_ioval_list locks special lockdep classes. Signed-off-by: <mgross@xxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- drivers/pci/intel-iommu.c | 7 +++++++ 1 file changed, 7 insertions(+) diff -puN drivers/pci/intel-iommu.c~iova-lockdep-false-alarm-fix drivers/pci/intel-iommu.c --- a/drivers/pci/intel-iommu.c~iova-lockdep-false-alarm-fix +++ a/drivers/pci/intel-iommu.c @@ -1097,6 +1097,8 @@ static void iommu_free_domain(struct dma } static struct iova_domain reserved_iova_list; +static struct lock_class_key reserved_alloc_key; +static struct lock_class_key reserved_rbtree_key; static void dmar_init_reserved_ranges(void) { @@ -1107,6 +1109,11 @@ static void dmar_init_reserved_ranges(vo init_iova_domain(&reserved_iova_list, DMA_32BIT_PFN); + lockdep_set_class(&reserved_iova_list.iova_alloc_lock, + &reserved_alloc_key); + lockdep_set_class(&reserved_iova_list.iova_rbtree_lock, + &reserved_rbtree_key); + /* IOAPIC ranges shouldn't be accessed by DMA */ iova = reserve_iova(&reserved_iova_list, IOVA_PFN(IOAPIC_RANGE_START), IOVA_PFN(IOAPIC_RANGE_END)); _ Patches currently in -mm which might be from mgross@xxxxxxxxxxxxxxx are pci-iova-rb-tree-setup-tweak.patch iova-lockdep-false-alarm-fix.patch - To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html