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authorBjörn Töpel <bjorn.topel@intel.com>2021-03-05 10:41:13 +0100
committerAndrii Nakryiko <andrii@kernel.org>2021-03-08 08:52:28 -0800
commit291471dd1559528a4c2ad5026eff94ed1030562b (patch)
treeaf863fd112a199148f11c746556393b48d9029d7 /tools/lib/bpf/xsk.h
parenta23b3f5697e6cf8affa7adf3e967e5ab569ea757 (diff)
libbpf, xsk: Add libbpf_smp_store_release libbpf_smp_load_acquire
Now that the AF_XDP rings have load-acquire/store-release semantics, move libbpf to that as well. The library-internal libbpf_smp_{load_acquire,store_release} are only valid for 32-bit words on ARM64. Also, remove the barriers that are no longer in use. Signed-off-by: Björn Töpel <bjorn.topel@intel.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Toke Høiland-Jørgensen <toke@redhat.com> Link: https://lore.kernel.org/bpf/20210305094113.413544-3-bjorn.topel@gmail.com
Diffstat (limited to 'tools/lib/bpf/xsk.h')
-rw-r--r--tools/lib/bpf/xsk.h17
1 files changed, 5 insertions, 12 deletions
diff --git a/tools/lib/bpf/xsk.h b/tools/lib/bpf/xsk.h
index e9f121f5d129..a9fdea87b5cd 100644
--- a/tools/lib/bpf/xsk.h
+++ b/tools/lib/bpf/xsk.h
@@ -96,7 +96,8 @@ static inline __u32 xsk_prod_nb_free(struct xsk_ring_prod *r, __u32 nb)
* this function. Without this optimization it whould have been
* free_entries = r->cached_prod - r->cached_cons + r->size.
*/
- r->cached_cons = *r->consumer + r->size;
+ r->cached_cons = libbpf_smp_load_acquire(r->consumer);
+ r->cached_cons += r->size;
return r->cached_cons - r->cached_prod;
}
@@ -106,7 +107,7 @@ static inline __u32 xsk_cons_nb_avail(struct xsk_ring_cons *r, __u32 nb)
__u32 entries = r->cached_prod - r->cached_cons;
if (entries == 0) {
- r->cached_prod = *r->producer;
+ r->cached_prod = libbpf_smp_load_acquire(r->producer);
entries = r->cached_prod - r->cached_cons;
}
@@ -129,9 +130,7 @@ static inline void xsk_ring_prod__submit(struct xsk_ring_prod *prod, __u32 nb)
/* Make sure everything has been written to the ring before indicating
* this to the kernel by writing the producer pointer.
*/
- libbpf_smp_wmb();
-
- *prod->producer += nb;
+ libbpf_smp_store_release(prod->producer, *prod->producer + nb);
}
static inline __u32 xsk_ring_cons__peek(struct xsk_ring_cons *cons, __u32 nb, __u32 *idx)
@@ -139,11 +138,6 @@ static inline __u32 xsk_ring_cons__peek(struct xsk_ring_cons *cons, __u32 nb, __
__u32 entries = xsk_cons_nb_avail(cons, nb);
if (entries > 0) {
- /* Make sure we do not speculatively read the data before
- * we have received the packet buffers from the ring.
- */
- libbpf_smp_rmb();
-
*idx = cons->cached_cons;
cons->cached_cons += entries;
}
@@ -161,9 +155,8 @@ static inline void xsk_ring_cons__release(struct xsk_ring_cons *cons, __u32 nb)
/* Make sure data has been read before indicating we are done
* with the entries by updating the consumer pointer.
*/
- libbpf_smp_rwmb();
+ libbpf_smp_store_release(cons->consumer, *cons->consumer + nb);
- *cons->consumer += nb;
}
static inline void *xsk_umem__get_data(void *umem_area, __u64 addr)