linux/include
Alexei Starovoitov 96049f3afd bpf: introduce BPF_F_LOCK flag
Introduce BPF_F_LOCK flag for map_lookup and map_update syscall commands
and for map_update() helper function.
In all these cases take a lock of existing element (which was provided
in BTF description) before copying (in or out) the rest of map value.

Implementation details that are part of uapi:

Array:
The array map takes the element lock for lookup/update.

Hash:
hash map also takes the lock for lookup/update and tries to avoid the bucket lock.
If old element exists it takes the element lock and updates the element in place.
If element doesn't exist it allocates new one and inserts into hash table
while holding the bucket lock.
In rare case the hashmap has to take both the bucket lock and the element lock
to update old value in place.

Cgroup local storage:
It is similar to array. update in place and lookup are done with lock taken.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-02-01 20:55:39 +01:00
..
acpi Merge branch 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-12-26 17:03:51 -08:00
asm-generic Merge branch 'akpm' (patches from Andrew) 2019-01-05 09:16:18 -08:00
clocksource
crypto crypto: skcipher - remove remnants of internal IV generators 2018-12-23 11:52:45 +08:00
drm Merge tag 'drm-intel-fixes-2019-01-11' of git://anongit.freedesktop.org/drm/drm-intel into drm-fixes 2019-01-11 10:26:21 +01:00
dt-bindings dt-bindings: reset: meson-axg: fix SPDX license id 2019-01-16 12:50:27 -06:00
keys
kvm KVM: arm/arm64: Remove arch timer workqueue 2018-12-19 17:47:07 +00:00
linux bpf: introduce BPF_F_LOCK flag 2019-02-01 20:55:39 +01:00
math-emu
media media fixes for v4.20-rc8 2018-12-25 13:11:30 -08:00
memory
misc
net sctp: add SCTP_FUTURE_ASOC and SCTP_CURRENT_ASSOC for SCTP_STREAM_SCHEDULER sockopt 2019-01-30 00:44:08 -08:00
pcmcia
ras
rdma IB/core: uverbs copy to struct or zero helper 2018-12-20 15:18:18 -07:00
scsi 4.21 merge window pull request 2018-12-28 14:57:10 -08:00
soc ARM: SoC driver updates 2018-12-31 17:32:35 -08:00
sound ASoC: Fixes for v5.0 2019-01-18 15:17:17 +01:00
target
trace mlxsw: spectrum_acl: Add C-TCAM spill tracepoint 2019-01-30 10:00:40 -08:00
uapi bpf: introduce BPF_F_LOCK flag 2019-02-01 20:55:39 +01:00
video
xen arm64/xen: fix xen-swiotlb cache flushing 2019-01-23 22:14:56 +01:00