Changes since v1 [1]: - Fix a NULL-pointer deref crash in pci_p2pdma_release() (Logan) - Refresh the p2pdma patch headers to match the format of other p2pdma patches (Bjorn) - Collect Ira's reviewed-by [1]: https://lore.kernel.org/lkml/155387324370.2443841.574715745262628837.stgit@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/ --- Logan audited the devm_memremap_pages() shutdown path and noticed that it was possible to proceed to arch_remove_memory() before all potential page references have been reaped. Introduce a new ->cleanup() callback to do the work of waiting for any straggling page references and then perform the percpu_ref_exit() in devm_memremap_pages_release() context. For p2pdma this involves some deeper reworks to reference count resources on a per-instance basis rather than a per pci-device basis. A modified genalloc api is introduced to convey a driver-private pointer through gen_pool_{alloc,free}() interfaces. Also, a devm_memunmap_pages() api is introduced since p2pdma does not auto-release resources on a setup failure. The dax and pmem changes pass the nvdimm unit tests, and the p2pdma changes should now pass testing with the pci_p2pdma_release() fix. Jérôme, how does this look for HMM? In general, I think these patches / fixes are suitable for v5.2-rc1 or v5.2-rc2, and since they touch kernel/memremap.c, and other various pieces of the core, they should go through the -mm tree. These patches merge cleanly with the current state of -next, pass the nvdimm unit tests, and are exposed to the 0day robot with no issues reported (https://git.kernel.org/pub/scm/linux/kernel/git/djbw/nvdimm.git/log/?h=libnvdimm-pending). --- Dan Williams (6): drivers/base/devres: Introduce devm_release_action() mm/devm_memremap_pages: Introduce devm_memunmap_pages PCI/P2PDMA: Fix the gen_pool_add_virt() failure path lib/genalloc: Introduce chunk owners PCI/P2PDMA: Track pgmap references per resource, not globally mm/devm_memremap_pages: Fix final page put race drivers/base/devres.c | 24 +++++++- drivers/dax/device.c | 13 +--- drivers/nvdimm/pmem.c | 17 ++++- drivers/pci/p2pdma.c | 115 +++++++++++++++++++++++-------------- include/linux/device.h | 1 include/linux/genalloc.h | 55 ++++++++++++++++-- include/linux/memremap.h | 8 +++ kernel/memremap.c | 23 ++++++- lib/genalloc.c | 51 ++++++++-------- mm/hmm.c | 14 +---- tools/testing/nvdimm/test/iomap.c | 2 + 11 files changed, 217 insertions(+), 106 deletions(-)
