From: Jérôme Glisse <jglisse@xxxxxxxxxx> Fixes and improvement to HMM only impact HMM user. Changes since the last posting: Allow release callback to wait on any device driver workqueue which is processing fault without having to worry for deadlock. Some driver do call migrate_vma() from their page fault workqueue which itself will trigger calls to mmu_notifier callback. If we take and keep the HMM semaphore in write mode while calling device driver release call back then those can not wait on their page fault workqueue as the workqueue might end up deadlocking (waiting to be able to take the HMM semaphore in read mode). Avoid this by dropping HMM semaphore while calling the device driver release callback. Other changes from previous post are solely typos fixes (in comment not in code), s/pfns/pfn for one function argument, and usual patch formatting fixes (also added review tag for review receive so far). Below are previous cover letter (everything in them are still true): ---------------------------------------------------------------------- cover letter for v3: Added a patch to fix zombie mm_struct (missing call to mmu notifier unregister) this was lost in translation at some point. Included all typos and comments received so far (and even more typos fixes). Added more comments. Updated individual patch version to reflect changes. ---------------------------------------------------------------------- cover letter for v2: Removed pointless VM_BUG_ON() cced stable when appropriate and splited the last patch into _many_ smaller patches to make it easier to review. The end result is same modulo comments i received so far and the extra documentation i added while splitting thing up. Below is previous cover letter (everything in it is still true): ---------------------------------------------------------------------- cover letter for v1: All patches only impact HMM user, there is no implication outside HMM. First patch improve documentation to better reflect what HMM is. Second patch fix #if/#else placement in hmm.h. The third patch add a call on mm release which helps device driver who use HMM to clean up early when a process quit. Finaly last patch modify the CPU snapshot and page fault helper to simplify device driver. The nouveau patchset i posted last week already depends on all of those patches. You can find them in a hmm-for-4.17 branch: git://people.freedesktop.org/~glisse/linux https://cgit.freedesktop.org/~glisse/linux/log/?h=hmm-for-4.17 Jérôme Glisse (13): mm/hmm: fix header file if/else/endif maze v2 mm/hmm: unregister mmu_notifier when last HMM client quit v3 mm/hmm: hmm_pfns_bad() was accessing wrong struct mm/hmm: use struct for hmm_vma_fault(), hmm_vma_get_pfns() parameters v2 mm/hmm: remove HMM_PFN_READ flag and ignore peculiar architecture v2 mm/hmm: use uint64_t for HMM pfn instead of defining hmm_pfn_t to ulong v2 mm/hmm: cleanup special vma handling (VM_SPECIAL) mm/hmm: do not differentiate between empty entry or missing directory v3 mm/hmm: rename HMM_PFN_DEVICE_UNADDRESSABLE to HMM_PFN_DEVICE_PRIVATE mm/hmm: move hmm_pfns_clear() closer to where it is use mm/hmm: factor out pte and pmd handling to simplify hmm_vma_walk_pmd() v2 mm/hmm: change hmm_vma_fault() to allow write fault on page basis mm/hmm: use device driver encoding for HMM pfn v2 Ralph Campbell (2): mm/hmm: documentation editorial update to HMM documentation mm/hmm: HMM should have a callback before MM is destroyed v3 Documentation/vm/hmm.txt | 360 +++++++++++++++--------------- MAINTAINERS | 1 + include/linux/hmm.h | 201 ++++++++++------- mm/hmm.c | 556 +++++++++++++++++++++++++++++++---------------- 4 files changed, 675 insertions(+), 443 deletions(-) -- 2.14.3
