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| author | Björn Töpel <bjorn.topel@intel.com> | 2021-03-10 11:09:28 +0300 |
|---|---|---|
| committer | Andrii Nakryiko <andrii@kernel.org> | 2021-03-11 00:38:07 +0300 |
| commit | 2882c48bf8f2fb9ec31cbb68be6b979da48f880d (patch) | |
| tree | a24609c89cad61c8033009f57967c525d44461da /tools | |
| parent | a9c80b03e586fd3819089fbd33c38fb65ad5e00c (diff) | |
| download | linux-2882c48bf8f2fb9ec31cbb68be6b979da48f880d.tar.xz | |
libbpf: xsk: Remove linux/compiler.h header
In commit 291471dd1559 ("libbpf, xsk: Add libbpf_smp_store_release
libbpf_smp_load_acquire") linux/compiler.h was added as a dependency
to xsk.h, which is the user-facing API. This makes it harder for
userspace application to consume the library. Here the header
inclusion is removed, and instead {READ,WRITE}_ONCE() is added
explicitly.
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210310080929.641212-2-bjorn.topel@gmail.com
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/lib/bpf/libbpf_util.h | 27 |
1 files changed, 17 insertions, 10 deletions
diff --git a/tools/lib/bpf/libbpf_util.h b/tools/lib/bpf/libbpf_util.h index cfbcfc063c81..954da9b34a34 100644 --- a/tools/lib/bpf/libbpf_util.h +++ b/tools/lib/bpf/libbpf_util.h @@ -5,25 +5,30 @@ #define __LIBBPF_LIBBPF_UTIL_H #include <stdbool.h> -#include <linux/compiler.h> #ifdef __cplusplus extern "C" { #endif -/* Use these barrier functions instead of smp_[rw]mb() when they are - * used in a libbpf header file. That way they can be built into the - * application that uses libbpf. +/* Load-Acquire Store-Release barriers used by the XDP socket + * library. The following macros should *NOT* be considered part of + * the xsk.h API, and is subject to change anytime. + * + * LIBRARY INTERNAL */ + +#define __XSK_READ_ONCE(x) (*(volatile typeof(x) *)&x) +#define __XSK_WRITE_ONCE(x, v) (*(volatile typeof(x) *)&x) = (v) + #if defined(__i386__) || defined(__x86_64__) # define libbpf_smp_store_release(p, v) \ do { \ asm volatile("" : : : "memory"); \ - WRITE_ONCE(*p, v); \ + __XSK_WRITE_ONCE(*p, v); \ } while (0) # define libbpf_smp_load_acquire(p) \ ({ \ - typeof(*p) ___p1 = READ_ONCE(*p); \ + typeof(*p) ___p1 = __XSK_READ_ONCE(*p); \ asm volatile("" : : : "memory"); \ ___p1; \ }) @@ -41,11 +46,11 @@ extern "C" { # define libbpf_smp_store_release(p, v) \ do { \ asm volatile ("fence rw,w" : : : "memory"); \ - WRITE_ONCE(*p, v); \ + __XSK_WRITE_ONCE(*p, v); \ } while (0) # define libbpf_smp_load_acquire(p) \ ({ \ - typeof(*p) ___p1 = READ_ONCE(*p); \ + typeof(*p) ___p1 = __XSK_READ_ONCE(*p); \ asm volatile ("fence r,rw" : : : "memory"); \ ___p1; \ }) @@ -55,19 +60,21 @@ extern "C" { #define libbpf_smp_store_release(p, v) \ do { \ __sync_synchronize(); \ - WRITE_ONCE(*p, v); \ + __XSK_WRITE_ONCE(*p, v); \ } while (0) #endif #ifndef libbpf_smp_load_acquire #define libbpf_smp_load_acquire(p) \ ({ \ - typeof(*p) ___p1 = READ_ONCE(*p); \ + typeof(*p) ___p1 = __XSK_READ_ONCE(*p); \ __sync_synchronize(); \ ___p1; \ }) #endif +/* LIBRARY INTERNAL -- END */ + #ifdef __cplusplus } /* extern "C" */ #endif |