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* RDMA/include: Replace license text with SPDX tagsLeon Romanovsky2020-07-291-28/+1
| | | | | | | | | | | The header files in RDMA subsystem are dual licensed and can be described by simple SPDX tag, so replace all of them at once together with making them use the same coding style for header guard defines. Link: https://lore.kernel.org/r/20200719072521.135260-1-leon@kernel.org Signed-off-by: Leon Romanovsky <leonro@mellanox.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
* IB: Allow calls to ib_umem_get from kernel ULPsMoni Shoua2020-01-161-3/+3
| | | | | | | | | | | | | | | So far the assumption was that ib_umem_get() and ib_umem_odp_get() are called from flows that start in UVERBS and therefore has a user context. This assumption restricts flows that are initiated by ULPs and need the service that ib_umem_get() provides. This patch changes ib_umem_get() and ib_umem_odp_get() to get IB device directly by relying on the fact that both UVERBS and ULPs sets that field correctly. Reviewed-by: Guy Levi <guyle@mellanox.com> Signed-off-by: Moni Shoua <monis@mellanox.com> Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
* RDMA/odp: Use mmu_interval_notifier_insert()Jason Gunthorpe2019-11-231-54/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Replace the internal interval tree based mmu notifier with the new common mmu_interval_notifier_insert() API. This removes a lot of code and fixes a deadlock that can be triggered in ODP: zap_page_range() mmu_notifier_invalidate_range_start() [..] ib_umem_notifier_invalidate_range_start() down_read(&per_mm->umem_rwsem) unmap_single_vma() [..] __split_huge_page_pmd() mmu_notifier_invalidate_range_start() [..] ib_umem_notifier_invalidate_range_start() down_read(&per_mm->umem_rwsem) // DEADLOCK mmu_notifier_invalidate_range_end() up_read(&per_mm->umem_rwsem) mmu_notifier_invalidate_range_end() up_read(&per_mm->umem_rwsem) The umem_rwsem is held across the range_start/end as the ODP algorithm for invalidate_range_end cannot tolerate changes to the interval tree. However, due to the nested invalidation regions the second down_read() can deadlock if there are competing writers. The new core code provides an alternative scheme to solve this problem. Fixes: ca748c39ea3f ("RDMA/umem: Get rid of per_mm->notifier_count") Link: https://lore.kernel.org/r/20191112202231.3856-6-jgg@ziepe.ca Tested-by: Artemy Kovalyov <artemyko@mellanox.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
* RDMA/mlx5: Rework implicit ODP destroyJason Gunthorpe2019-10-281-2/+0
| | | | | | | | | | | | | | | | | | | Use SRCU in a sensible way by removing all MRs in the implicit tree from the two xarrays (the update operation), then a synchronize, followed by a normal single threaded teardown. This is only a little unusual from the normal pattern as there can still be some work pending in the unbound wq that may also require a workqueue flush. This is tracked with a single atomic, consolidating the redundant existing atomics and wait queue. For understand-ability the entire ODP implicit create/destroy flow now largely exists in a single pair of functions within odp.c, with a few support functions for tearing down an unused child. Link: https://lore.kernel.org/r/20191009160934.3143-13-jgg@ziepe.ca Reviewed-by: Artemy Kovalyov <artemyko@mellanox.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
* RDMA/mlx5: Use an xarray for the children of an implicit ODPJason Gunthorpe2019-10-281-16/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | Currently the child leaves are stored in the shared interval tree and every lookup for a child must be done under the interval tree rwsem. This is further complicated by dropping the rwsem during iteration (ie the odp_lookup(), odp_next() pattern), which requires a very tricky an difficult to understand locking scheme with SRCU. Instead reserve the interval tree for the exclusive use of the mmu notifier related code in umem_odp.c and give each implicit MR a xarray containing all the child MRs. Since the size of each child is 1GB of VA, a 1 level xarray will index 64G of VA, and a 2 level will index 2TB, making xarray a much better data structure choice than an interval tree. The locking properties of xarray will be used in the next patches to rework the implicit ODP locking scheme into something simpler. At this point, the xarray is locked by the implicit MR's umem_mutex, and read can also be locked by the odp_srcu. Link: https://lore.kernel.org/r/20191009160934.3143-10-jgg@ziepe.ca Reviewed-by: Artemy Kovalyov <artemyko@mellanox.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
* RDMA/odp: use mmu_notifier_get/put for 'struct ib_ucontext_per_mm'Jason Gunthorpe2019-08-211-9/+1
| | | | | | | | | This is a significant simplification, no extra list is kept per FD, and the interval tree is now shared between all the ucontexts, reducing overhead if there are multiple ucontexts active. Link: https://lore.kernel.org/r/20190806231548.25242-7-jgg@ziepe.ca Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
* RDMA/odp: Check for overflow when computing the umem_odp endJason Gunthorpe2019-08-211-3/+2
| | | | | | | | | | | | | Since the page size can be extended in the ODP case by IB_ACCESS_HUGETLB the existing overflow checks done by ib_umem_get() are not sufficient. Check for overflow again. Further, remove the unchecked math from the inlines and just use the precomputed value stored in the interval_tree_node. Link: https://lore.kernel.org/r/20190819111710.18440-9-leon@kernel.org Signed-off-by: Leon Romanovsky <leonro@mellanox.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
* RDMA/odp: Split creating a umem_odp from ib_umem_getJason Gunthorpe2019-08-211-3/+6
| | | | | | | | | | This is the last creation API that is overloaded for both, there is very little code sharing and a driver has to be specifically ready for a umem_odp to be created to use the odp version. Link: https://lore.kernel.org/r/20190819111710.18440-7-leon@kernel.org Signed-off-by: Leon Romanovsky <leonro@mellanox.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
* RDMA/odp: Make the three ways to create a umem_odp clearJason Gunthorpe2019-08-211-2/+4
| | | | | | | | | | | | | | | | | The three paths to build the umem_odps are kind of muddled, they are: - As a normal ib_mr umem - As a child in an implicit ODP umem tree - As the root of an implicit ODP umem tree Only the first two are actually umem's, the last is an abuse. The implicit case can only be triggered by explicit driver request, it should never be co-mingled with the normal case. While we are here, make sensible function names and add some comments to make this clearer. Link: https://lore.kernel.org/r/20190819111710.18440-6-leon@kernel.org Signed-off-by: Leon Romanovsky <leonro@mellanox.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
* RDMA/odp: Make it clearer when a umem is an implicit ODP umemJason Gunthorpe2019-08-211-0/+8
| | | | | | | | | | | | | | Implicit ODP umems are special, they don't have any page lists, they don't exist in the interval tree and they are never DMA mapped. Instead of trying to guess this based on a zero length use an explicit flag. Further, do not allow non-implicit umems to be 0 size. Link: https://lore.kernel.org/r/20190819111710.18440-4-leon@kernel.org Signed-off-by: Leon Romanovsky <leonro@mellanox.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
* RDMA/odp: Use the common interval tree library instead of genericJason Gunthorpe2019-08-211-8/+12
| | | | | | | | | | | | | | | | | ODP is working with userspace VA's in the interval tree which always fit into an unsigned long, so we can use the common code. This comes at a cost of a 16 byte increase in ib_umem_odp struct size due to storing the interval tree start/last in addition to the umem addr/length. However these values were computed and are performance critical for the interval lookup, so this seems like a worthwhile trade off. Removes 2k of .text from the kernel. Link: https://lore.kernel.org/r/20190819111710.18440-2-leon@kernel.org Signed-off-by: Leon Romanovsky <leonro@mellanox.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
* RDMA/umem: Move page_shift from ib_umem to ib_odp_umemJason Gunthorpe2019-05-211-0/+20
| | | | | | | | | | | This value has always been set to PAGE_SHIFT in the core code, the only thing that does differently was the ODP path. Move the value into the ODP struct and still use it for ODP, but change all the non-ODP things to just use PAGE_SHIFT/PAGE_SIZE/PAGE_MASK directly. Reviewed-by: Shiraz Saleem <shiraz.saleem@intel.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com> Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
* RDMA/umem: Combine contiguous PAGE_SIZE regions in SGEsShiraz Saleem2019-04-081-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | Combine contiguous regions of PAGE_SIZE pages into single scatter list entry while building the scatter table for a umem. This minimizes the number of the entries in the scatter list and reduces the DMA mapping overhead, particularly with the IOMMU. Set default max_seg_size in core for IB devices to 2G and do not combine if we exceed this limit. Also, purge npages in struct ib_umem as we now DMA map the umem SGL with sg_nents and npage computation is not needed. Drivers should now be using ib_umem_num_pages(), so fix the last stragglers. Move npages tracking to ib_umem_odp as ODP drivers still need it. Suggested-by: Jason Gunthorpe <jgg@ziepe.ca> Reviewed-by: Michael J. Ruhl <michael.j.ruhl@intel.com> Reviewed-by: Ira Weiny <ira.weiny@intel.com> Acked-by: Adit Ranadive <aditr@vmware.com> Signed-off-by: Shiraz Saleem <shiraz.saleem@intel.com> Tested-by: Gal Pressman <galpress@amazon.com> Tested-by: Selvin Xavier <selvin.xavier@broadcom.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
* IB/mlx5: Remove dead codeMoni Shoua2019-01-241-6/+0
| | | | | | | | | | When CONFIG_INFINIBAND_ON_DEMAND_PAGING is not set there is no caller to ib_alloc_odp_umem() so let's remove it. Signed-off-by: Moni Shoua <monis@mellanox.com> Reviewed-by: Artemy Kovalyov <artemyko@mellanox.com> Signed-off-by: Leon Romanovsky <leonro@mellanox.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
* IB/mlx5: Ranges in implicit ODP MR inherit its write accessMoni Shoua2019-01-241-1/+1
| | | | | | | | | | | A sub-range in ODP implicit MR should take its write permission from the MR and not be set always to allow. Fixes: d07d1d70ce1a ("IB/umem: Update on demand page (ODP) support") Signed-off-by: Moni Shoua <monis@mellanox.com> Reviewed-by: Artemy Kovalyov <artemyko@mellanox.com> Signed-off-by: Leon Romanovsky <leonro@mellanox.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
* RDMA/mlx5: Embed into the code flow the ODP config optionLeon Romanovsky2019-01-081-13/+13
| | | | | | | | Convert various places to more readable code, which embeds CONFIG_INFINIBAND_ON_DEMAND_PAGING into the code flow. Signed-off-by: Leon Romanovsky <leonro@mellanox.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
* RDMA/umem: Avoid synchronize_srcu in the ODP MR destruction pathJason Gunthorpe2018-09-211-0/+1
| | | | | | | | | | synchronize_rcu is slow enough that it should be avoided on the syscall path when user space is destroying MRs. After all the rework we can now trivially do this by having call_srcu kfree the per_mm. Signed-off-by: Jason Gunthorpe <jgg@mellanox.com> Signed-off-by: Leon Romanovsky <leonro@mellanox.com> Signed-off-by: Doug Ledford <dledford@redhat.com>
* RDMA/umem: Handle a half-complete start/end sequenceJason Gunthorpe2018-09-211-0/+1
| | | | | | | | | | | | | | | | | mmu_notifier_unregister() can race between a invalidate_start/end and cause the invalidate_end to be skipped. This causes an imbalance in the locking, which lockdep complains about. This is not actually a bug, as we immediately kfree the memory holding the lock, but it simple enough to fix. Mark when the notifier is being destroyed and abort the start callback. This can be done under the lock we already obtained, and can re-purpose the invalidate_range test we already have. Signed-off-by: Jason Gunthorpe <jgg@mellanox.com> Signed-off-by: Leon Romanovsky <leonro@mellanox.com> Signed-off-by: Doug Ledford <dledford@redhat.com>
* RDMA/umem: Get rid of per_mm->notifier_countJason Gunthorpe2018-09-211-15/+0
| | | | | | | | | | | | | | | | | | | | | | | | | This is intrinsically racy and the scheme is simply unnecessary. New MR registration can wait for any on going invalidation to fully complete. CPU0 CPU1 if (atomic_read()) if (atomic_dec_and_test() && !list_empty()) { /* not taken */ } list_add() Putting the new UMEM into some kind of purgatory until another invalidate rolls through.. Instead hold the read side of the umem_rwsem across the pair'd start/end and get rid of the racy 'deferred add' approach. Since all umem's in the rbt are always ready to go, also get rid of the mn_counters_active stuff. Signed-off-by: Jason Gunthorpe <jgg@mellanox.com> Signed-off-by: Leon Romanovsky <leonro@mellanox.com> Signed-off-by: Doug Ledford <dledford@redhat.com>
* RDMA/umem: Use umem->owning_mm inside ODPJason Gunthorpe2018-09-211-1/+19
| | | | | | | | | | | | | | | | | | | | Since ODP had a single struct mmu_notifier located in the ucontext it could only handle a single MM at a time, and this prevented it from using the new owning_mm system. With the prior rework it is now simple to let ODP track multiple MMs per ucontext, finish the job so that the per_mm is allocated on a mm by mm basis, and freed when the last umem is dropped from the ucontext. As a side effect the new saner locking removes the lockdep splat about nesting the umem_rwsem between mmu_notifier_unregister and ib_umem_odp_release. It also makes ODP work with multiple processes, across, fork, etc. Signed-off-by: Jason Gunthorpe <jgg@mellanox.com> Signed-off-by: Leon Romanovsky <leonro@mellanox.com> Signed-off-by: Doug Ledford <dledford@redhat.com>
* RDMA/umem: Move all the ODP related stuff out of ucontext and into per_mmJason Gunthorpe2018-09-211-0/+2
| | | | | | | | | | | | | | | | | This is the first step to make ODP use the owning_mm that is now part of struct ib_umem. Each ODP umem is linked to a single per_mm structure, which in turn, is linked to a single mm, via the embedded mmu_notifier. This first patch introduces the structure and reworks eveything to use it. This also needs to introduce tgid into the ib_ucontext_per_mm, as get_user_pages_remote() requires the originating task for statistics tracking. Signed-off-by: Jason Gunthorpe <jgg@mellanox.com> Signed-off-by: Leon Romanovsky <leonro@mellanox.com> Signed-off-by: Doug Ledford <dledford@redhat.com>
* RDMA/umem: Make ib_umem_odp into a sub structure of ib_umemJason Gunthorpe2018-09-211-7/+4
| | | | | | | | | | These two structures are linked together, use the container_of pattern instead of a double allocation to make the code simpler and easier to follow. Signed-off-by: Jason Gunthorpe <jgg@mellanox.com> Signed-off-by: Leon Romanovsky <leonro@mellanox.com> Signed-off-by: Doug Ledford <dledford@redhat.com>
* RDMA/umem: Use ib_umem_odp in all function signatures connected to ODPJason Gunthorpe2018-09-211-18/+21
| | | | | | | | | | | All of these functions already require the ODP version of the umem struct, make this very clear by having the signature require it. This paves the way to using the container_of() pattern to link umem_odp and umem together. Signed-off-by: Jason Gunthorpe <jgg@mellanox.com> Signed-off-by: Leon Romanovsky <leonro@mellanox.com> Signed-off-by: Doug Ledford <dledford@redhat.com>
* mm, oom: distinguish blockable mode for mmu notifiersMichal Hocko2018-08-221-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There are several blockable mmu notifiers which might sleep in mmu_notifier_invalidate_range_start and that is a problem for the oom_reaper because it needs to guarantee a forward progress so it cannot depend on any sleepable locks. Currently we simply back off and mark an oom victim with blockable mmu notifiers as done after a short sleep. That can result in selecting a new oom victim prematurely because the previous one still hasn't torn its memory down yet. We can do much better though. Even if mmu notifiers use sleepable locks there is no reason to automatically assume those locks are held. Moreover majority of notifiers only care about a portion of the address space and there is absolutely zero reason to fail when we are unmapping an unrelated range. Many notifiers do really block and wait for HW which is harder to handle and we have to bail out though. This patch handles the low hanging fruit. __mmu_notifier_invalidate_range_start gets a blockable flag and callbacks are not allowed to sleep if the flag is set to false. This is achieved by using trylock instead of the sleepable lock for most callbacks and continue as long as we do not block down the call chain. I think we can improve that even further because there is a common pattern to do a range lookup first and then do something about that. The first part can be done without a sleeping lock in most cases AFAICS. The oom_reaper end then simply retries if there is at least one notifier which couldn't make any progress in !blockable mode. A retry loop is already implemented to wait for the mmap_sem and this is basically the same thing. The simplest way for driver developers to test this code path is to wrap userspace code which uses these notifiers into a memcg and set the hard limit to hit the oom. This can be done e.g. after the test faults in all the mmu notifier managed memory and set the hard limit to something really small. Then we are looking for a proper process tear down. [akpm@linux-foundation.org: coding style fixes] [akpm@linux-foundation.org: minor code simplification] Link: http://lkml.kernel.org/r/20180716115058.5559-1-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Christian König <christian.koenig@amd.com> # AMD notifiers Acked-by: Leon Romanovsky <leonro@mellanox.com> # mlx and umem_odp Reported-by: David Rientjes <rientjes@google.com> Cc: "David (ChunMing) Zhou" <David1.Zhou@amd.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Alex Deucher <alexander.deucher@amd.com> Cc: David Airlie <airlied@linux.ie> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com> Cc: Doug Ledford <dledford@redhat.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Mike Marciniszyn <mike.marciniszyn@intel.com> Cc: Dennis Dalessandro <dennis.dalessandro@intel.com> Cc: Sudeep Dutt <sudeep.dutt@intel.com> Cc: Ashutosh Dixit <ashutosh.dixit@intel.com> Cc: Dimitri Sivanich <sivanich@sgi.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Juergen Gross <jgross@suse.com> Cc: "Jérôme Glisse" <jglisse@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Felix Kuehling <felix.kuehling@amd.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* RDMA/umem: Avoid partial declaration of non-static functionLeon Romanovsky2017-11-101-4/+0
| | | | | | | | | | | | | | | | | | | | | | | | The RDMA/umem uses generic RB-trees macros to generate various ib_umem access functions. The generation is performed with INTERVAL_TREE_DEFINE macro, which allows one of two modes: declare all functions as static or declare none of the function to be static. The second mode of operation produces the following sparse errors: drivers/infiniband/core/umem_rbtree.c:69:1: warning: symbol 'rbt_ib_umem_iter_first' was not declared. Should it be static? drivers/infiniband/core/umem_rbtree.c:69:1: warning: symbol 'rbt_ib_umem_iter_next' was not declared. Should it be static? Code relocation together with declaration of such functions to be "static" solves the issue. Because there is no need to have separate file for two functions, let's consolidate umem_rtree.c and umem_odp.c into one file. Signed-off-by: Leon Romanovsky <leonro@mellanox.com> Signed-off-by: Doug Ledford <dledford@redhat.com>
* lib/interval_tree: fast overlap detectionDavidlohr Bueso2017-09-081-4/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | Allow interval trees to quickly check for overlaps to avoid unnecesary tree lookups in interval_tree_iter_first(). As of this patch, all interval tree flavors will require using a 'rb_root_cached' such that we can have the leftmost node easily available. While most users will make use of this feature, those with special functions (in addition to the generic insert, delete, search calls) will avoid using the cached option as they can do funky things with insertions -- for example, vma_interval_tree_insert_after(). [jglisse@redhat.com: fix deadlock from typo vm_lock_anon_vma()] Link: http://lkml.kernel.org/r/20170808225719.20723-1-jglisse@redhat.com Link: http://lkml.kernel.org/r/20170719014603.19029-12-dave@stgolabs.net Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Signed-off-by: Jérôme Glisse <jglisse@redhat.com> Acked-by: Christian König <christian.koenig@amd.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Doug Ledford <dledford@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Cc: David Airlie <airlied@linux.ie> Cc: Jason Wang <jasowang@redhat.com> Cc: Christian Benvenuti <benve@cisco.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* IB/umem: Add support to huge ODPArtemy Kovalyov2017-04-251-2/+4
| | | | | | | | | | Add IB_ACCESS_HUGETLB ib_reg_mr flag. Hugetlb region registered with this flag will use single translation entry per huge page. Signed-off-by: Artemy Kovalyov <artemyko@mellanox.com> Signed-off-by: Leon Romanovsky <leon@kernel.org> Signed-off-by: Doug Ledford <dledford@redhat.com>
* IB/umem: Update on demand page (ODP) supportArtemy Kovalyov2017-02-141-4/+17
| | | | | | | | | | | | | | | | | | | | Currently ODP MR may explicitly register virtual address space area of limited length. This change allows MR to cover entire process virtual address space dynamicaly adding/removing translation entries to device MTT. Add following changes to support implicit MR: * Allow umem to be zero size to back-up implicit MR. * Add new function ib_alloc_odp_umem() to add virtual memory regions to implicit MR dynamically on demand. * Add new function rbt_ib_umem_lookup() to find dynamically added virtual memory regions. * Expose function rbt_ib_umem_for_each_in_range() to other modules and make it safe Signed-off-by: Artemy Kovalyov <artemyko@mellanox.com> Signed-off-by: Leon Romanovsky <leon@kernel.org> Signed-off-by: Doug Ledford <dledford@redhat.com>
* IB/core: Implement support for MMU notifiers regarding on demand paging regionsHaggai Eran2014-12-151-1/+64
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * Add an interval tree implementation for ODP umems. Create an interval tree for each ucontext (including a count of the number of ODP MRs in this context, semaphore, etc.), and register ODP umems in the interval tree. * Add MMU notifiers handling functions, using the interval tree to notify only the relevant umems and underlying MRs. * Register to receive MMU notifier events from the MM subsystem upon ODP MR registration (and unregister accordingly). * Add a completion object to synchronize the destruction of ODP umems. * Add mechanism to abort page faults when there's a concurrent invalidation. The way we synchronize between concurrent invalidations and page faults is by keeping a counter of currently running invalidations, and a sequence number that is incremented whenever an invalidation is caught. The page fault code checks the counter and also verifies that the sequence number hasn't progressed before it updates the umem's page tables. This is similar to what the kvm module does. In order to prevent the case where we register a umem in the middle of an ongoing notifier, we also keep a per ucontext counter of the total number of active mmu notifiers. We only enable new umems when all the running notifiers complete. Signed-off-by: Sagi Grimberg <sagig@mellanox.com> Signed-off-by: Shachar Raindel <raindel@mellanox.com> Signed-off-by: Haggai Eran <haggaie@mellanox.com> Signed-off-by: Yuval Dagan <yuvalda@mellanox.com> Signed-off-by: Roland Dreier <roland@purestorage.com>
* IB/core: Add support for on demand paging regionsShachar Raindel2014-12-151-0/+97
* Extend the umem struct to keep the ODP related data. * Allocate and initialize the ODP related information in the umem (page_list, dma_list) and freeing as needed in the end of the run. * Store a reference to the process PID struct in the ucontext. Used to safely obtain the task_struct and the mm during fault handling, without preventing the task destruction if needed. * Add 2 helper functions: ib_umem_odp_map_dma_pages and ib_umem_odp_unmap_dma_pages. These functions get the DMA addresses of specific pages of the umem (and, currently, pin them). * Support for page faults only - IB core will keep the reference on the pages used and call put_page when freeing an ODP umem area. Invalidations support will be added in a later patch. Signed-off-by: Sagi Grimberg <sagig@mellanox.com> Signed-off-by: Shachar Raindel <raindel@mellanox.com> Signed-off-by: Haggai Eran <haggaie@mellanox.com> Signed-off-by: Majd Dibbiny <majd@mellanox.com> Signed-off-by: Roland Dreier <roland@purestorage.com>
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