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authorBjörn Töpel <bjorn.topel@intel.com>2018-08-10 12:28:02 +0300
committerDaniel Borkmann <daniel@iogearbox.net>2018-08-10 17:06:48 +0300
commiteb91e4d4db06adef06e7f50c02813c13c6ca5a5b (patch)
treef721fe92f603de042c70d5ffee725c226488873e
parenta736e074680745faa5dc6be8dd3c58ad4850aab9 (diff)
downloadlinux-eb91e4d4db06adef06e7f50c02813c13c6ca5a5b.tar.xz
Revert "xdp: add NULL pointer check in __xdp_return()"
This reverts commit 36e0f12bbfd3016f495904b35e41c5711707509f. The reverted commit adds a WARN to check against NULL entries in the mem_id_ht rhashtable. Any kernel path implementing the XDP (generic or driver) fast path is required to make a paired xdp_rxq_info_reg/xdp_rxq_info_unreg call for proper function. In addition, a driver using a different allocation scheme than the default MEM_TYPE_PAGE_SHARED is required to additionally call xdp_rxq_info_reg_mem_model. For MEM_TYPE_ZERO_COPY, an xdp_rxq_info_reg_mem_model call ensures that the mem_id_ht rhashtable has a properly inserted allocator id. If not, this would be a driver bug. A NULL pointer kernel OOPS is preferred to the WARN. Suggested-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Björn Töpel <bjorn.topel@intel.com> Acked-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
-rw-r--r--net/core/xdp.c3
1 files changed, 1 insertions, 2 deletions
diff --git a/net/core/xdp.c b/net/core/xdp.c
index c013b836006b..57285383ed00 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c
@@ -348,8 +348,7 @@ static void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct,
rcu_read_lock();
/* mem->id is valid, checked in xdp_rxq_info_reg_mem_model() */
xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params);
- if (!WARN_ON_ONCE(!xa))
- xa->zc_alloc->free(xa->zc_alloc, handle);
+ xa->zc_alloc->free(xa->zc_alloc, handle);
rcu_read_unlock();
default:
/* Not possible, checked in xdp_rxq_info_reg_mem_model() */