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2023-07-11libbpf: Remove HASHMAP_INIT static initialization helperJohn Sanpe1-10/+0
Remove the wrong HASHMAP_INIT. It's not used anywhere in libbpf. Signed-off-by: John Sanpe <sanpeqf@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20230711070712.2064144-1-sanpeqf@gmail.com
2022-11-11libbpf: Hashmap.h update to fix build issues using LLVM14Eduard Zingerman1-1/+2
A fix for the LLVM compilation error while building bpftool. Replaces the expression: _Static_assert((p) == NULL || ...) by expression: _Static_assert((__builtin_constant_p((p)) ? (p) == NULL : 0) || ...) When "p" is not a constant the former is not considered to be a constant expression by LLVM 14. The error was introduced in the following patch-set: [1]. The error was reported here: [2]. [1] https://lore.kernel.org/bpf/20221109142611.879983-1-eddyz87@gmail.com/ [2] https://lore.kernel.org/all/202211110355.BcGcbZxP-lkp@intel.com/ Reported-by: kernel test robot <lkp@intel.com> Fixes: c302378bc157 ("libbpf: Hashmap interface update to allow both long and void* keys/values") Signed-off-by: Eduard Zingerman <eddyz87@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Stanislav Fomichev <sdf@google.com> Link: https://lore.kernel.org/bpf/20221110223240.1350810-1-eddyz87@gmail.com
2022-11-10libbpf: Hashmap interface update to allow both long and void* keys/valuesEduard Zingerman1-34/+56
An update for libbpf's hashmap interface from void* -> void* to a polymorphic one, allowing both long and void* keys and values. This simplifies many use cases in libbpf as hashmaps there are mostly integer to integer. Perf copies hashmap implementation from libbpf and has to be updated as well. Changes to libbpf, selftests/bpf and perf are packed as a single commit to avoid compilation issues with any future bisect. Polymorphic interface is acheived by hiding hashmap interface functions behind auxiliary macros that take care of necessary type casts, for example: #define hashmap_cast_ptr(p) \ ({ \ _Static_assert((p) == NULL || sizeof(*(p)) == sizeof(long),\ #p " pointee should be a long-sized integer or a pointer"); \ (long *)(p); \ }) bool hashmap_find(const struct hashmap *map, long key, long *value); #define hashmap__find(map, key, value) \ hashmap_find((map), (long)(key), hashmap_cast_ptr(value)) - hashmap__find macro casts key and value parameters to long and long* respectively - hashmap_cast_ptr ensures that value pointer points to a memory of appropriate size. This hack was suggested by Andrii Nakryiko in [1]. This is a follow up for [2]. [1] https://lore.kernel.org/bpf/CAEf4BzZ8KFneEJxFAaNCCFPGqp20hSpS2aCj76uRk3-qZUH5xg@mail.gmail.com/ [2] https://lore.kernel.org/bpf/af1facf9-7bc8-8a3d-0db4-7b3f333589a2@meta.com/T/#m65b28f1d6d969fcd318b556db6a3ad499a42607d Signed-off-by: Eduard Zingerman <eddyz87@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20221109142611.879983-2-eddyz87@gmail.com
2020-11-03libbpf, hashmap: Fix undefined behavior in hash_bitsIan Rogers1-6/+9
If bits is 0, the case when the map is empty, then the >> is the size of the register which is undefined behavior - on x86 it is the same as a shift by 0. Fix by handling the 0 case explicitly and guarding calls to hash_bits for empty maps in hashmap__for_each_key_entry and hashmap__for_each_entry_safe. Fixes: e3b924224028 ("libbpf: add resizable non-thread safe internal hashmap") Suggested-by: Andrii Nakryiko <andriin@fb.com>, Signed-off-by: Ian Rogers <irogers@google.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20201029223707.494059-1-irogers@google.com
2020-09-29libbpf: Extract generic string hashing function for reuseAndrii Nakryiko1-0/+12
Calculating a hash of zero-terminated string is a common need when using hashmap, so extract it for reuse. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20200926011357.2366158-5-andriin@fb.com
2020-07-10libbpf: Fix libbpf hashmap on (I)LP32 architecturesJakub Bogusz1-4/+8
On ILP32, 64-bit result was shifted by value calculated for 32-bit long type and returned value was much outside hashmap capacity. As advised by Andrii Nakryiko, this patch uses different hashing variant for architectures with size_t shorter than long long. Fixes: e3b924224028 ("libbpf: add resizable non-thread safe internal hashmap") Signed-off-by: Jakub Bogusz <qboosh@pld-linux.org> Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200709225723.1069937-1-andriin@fb.com
2020-06-10libbpf: Define __WORDSIZE if not availableArnaldo Carvalho de Melo1-4/+3
Some systems, such as Android, don't have a define for __WORDSIZE, do it in terms of __SIZEOF_LONG__, as done in perf since 2012: http://git.kernel.org/torvalds/c/3f34f6c0233ae055b5 For reference: https://gcc.gnu.org/onlinedocs/cpp/Common-Predefined-Macros.html I build tested it here and Andrii did some Travis CI build tests too. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20200608161150.GA3073@kernel.org
2020-05-16libbpf, hashmap: Remove unused #includeIan Rogers1-1/+0
Remove #include of libbpf_internal.h that is unused. Discussed in this thread: https://lore.kernel.org/lkml/CAEf4BzZRmiEds_8R8g4vaAeWvJzPb4xYLnpF0X2VNY8oTzkphQ@mail.gmail.com/ Signed-off-by: Ian Rogers <irogers@google.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20200515165007.217120-3-irogers@google.com
2019-07-29libbpf: fix missing __WORDSIZE definitionAndrii Nakryiko1-0/+5
hashmap.h depends on __WORDSIZE being defined. It is defined by glibc/musl in different headers. It's an explicit goal for musl to be "non-detectable" at compilation time, so instead include glibc header if glibc is explicitly detected and fall back to musl header otherwise. Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Andrii Nakryiko <andriin@fb.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexei Starovoitov <ast@fb.com> Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Fixes: e3b924224028 ("libbpf: add resizable non-thread safe internal hashmap") Link: https://lkml.kernel.org/r/20190718173021.2418606-1-andriin@fb.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-05-25libbpf: add resizable non-thread safe internal hashmapAndrii Nakryiko1-0/+173
There is a need for fast point lookups inside libbpf for multiple use cases (e.g., name resolution for BTF-to-C conversion, by-name lookups in BTF for upcoming BPF CO-RE relocation support, etc). This patch implements simple resizable non-thread safe hashmap using single linked list chains. Four different insert strategies are supported: - HASHMAP_ADD - only add key/value if key doesn't exist yet; - HASHMAP_SET - add key/value pair if key doesn't exist yet; otherwise, update value; - HASHMAP_UPDATE - update value, if key already exists; otherwise, do nothing and return -ENOENT; - HASHMAP_APPEND - always add key/value pair, even if key already exists. This turns hashmap into a multimap by allowing multiple values to be associated with the same key. Most useful read API for such hashmap is hashmap__for_each_key_entry() iteration. If hashmap__find() is still used, it will return last inserted key/value entry (first in a bucket chain). For HASHMAP_SET and HASHMAP_UPDATE, old key/value pair is returned, so that calling code can handle proper memory management, if necessary. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>