Add support for kptrs in more BPF maps #4674
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Upstream branch: 68bfd65 |
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Enable support for kptrs in percpu BPF hashmap and percpu BPF LRU hashmap by wiring up the freeing of these kptrs from percpu map elements. Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
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Upstream branch: 84c22fa |
Enable support for kptrs in local storage maps by wiring up the freeing of these kptrs from map value. Freeing of bpf_local_storage_map is only delayed in case there are special fields, therefore bpf_selem_free_* path can also only dereference smap safely in that case. This is recorded using a bool utilizing a hole in bpF_local_storage_elem. It could have been tagged in the pointer value smap using the lowest bit (since alignment > 1), but since there was already a hole I went with the simpler option. Only the map structure freeing is delayed using RCU barriers, as the buckets aren't used when selem is being freed, so they can be freed once all readers of the bucket lists can no longer access it. Cc: Martin KaFai Lau <martin.lau@kernel.org> Cc: KP Singh <kpsingh@kernel.org> Cc: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Firstly, ensure programs successfully load when using all of the supported maps. Then, extend existing tests to test more cases at runtime. We are currently testing both the synchronous freeing of items and asynchronous destruction when map is freed, but the code needs to be adjusted a bit to be able to also accomodate support for percpu maps. We now do a delete on the item (and update for array maps which has a similar effect for kptrs) to perform a synchronous free of the kptr, and test destruction both for the synchronous and asynchronous deletion. Next time the program runs, it should observe the refcount as 1 since all existing references should have been released by then. By running the program after both possible paths freeing kptrs, we establish that they correctly release resources. Next, we augment the existing test to also test the same code path shared by all local storage maps using a task local storage map. Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
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At least one diff in series https://patchwork.kernel.org/project/netdevbpf/list/?series=724857 expired. Closing PR. |
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Pull request for series with
subject: Add support for kptrs in more BPF maps
version: 3
url: https://patchwork.kernel.org/project/netdevbpf/list/?series=724857