diff options
Diffstat (limited to 'net/core/skbuff.c')
| -rw-r--r-- | net/core/skbuff.c | 47 |
1 files changed, 31 insertions, 16 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c index eb7d33b41e71..4c0879798eb8 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -517,18 +517,16 @@ static void *kmalloc_reserve(unsigned int *size, gfp_t flags, int node, #ifdef HAVE_SKB_SMALL_HEAD_CACHE if (obj_size <= SKB_SMALL_HEAD_CACHE_SIZE && !(flags & KMALLOC_NOT_NORMAL_BITS)) { - - /* skb_small_head_cache has non power of two size, - * likely forcing SLUB to use order-3 pages. - * We deliberately attempt a NOMEMALLOC allocation only. - */ obj = kmem_cache_alloc_node(skb_small_head_cache, flags | __GFP_NOMEMALLOC | __GFP_NOWARN, node); - if (obj) { - *size = SKB_SMALL_HEAD_CACHE_SIZE; + *size = SKB_SMALL_HEAD_CACHE_SIZE; + if (obj || !(gfp_pfmemalloc_allowed(flags))) goto out; - } + /* Try again but now we are using pfmemalloc reserves */ + ret_pfmemalloc = true; + obj = kmem_cache_alloc_node(skb_small_head_cache, flags, node); + goto out; } #endif *size = obj_size = kmalloc_size_roundup(obj_size); @@ -2082,6 +2080,7 @@ struct sk_buff *skb_realloc_headroom(struct sk_buff *skb, unsigned int headroom) } EXPORT_SYMBOL(skb_realloc_headroom); +/* Note: We plan to rework this in linux-6.4 */ int __skb_unclone_keeptruesize(struct sk_buff *skb, gfp_t pri) { unsigned int saved_end_offset, saved_truesize; @@ -2100,6 +2099,22 @@ int __skb_unclone_keeptruesize(struct sk_buff *skb, gfp_t pri) if (likely(skb_end_offset(skb) == saved_end_offset)) return 0; +#ifdef HAVE_SKB_SMALL_HEAD_CACHE + /* We can not change skb->end if the original or new value + * is SKB_SMALL_HEAD_HEADROOM, as it might break skb_kfree_head(). + */ + if (saved_end_offset == SKB_SMALL_HEAD_HEADROOM || + skb_end_offset(skb) == SKB_SMALL_HEAD_HEADROOM) { + /* We think this path should not be taken. + * Add a temporary trace to warn us just in case. + */ + pr_err_once("__skb_unclone_keeptruesize() skb_end_offset() %u -> %u\n", + saved_end_offset, skb_end_offset(skb)); + WARN_ON_ONCE(1); + return 0; + } +#endif + shinfo = skb_shinfo(skb); /* We are about to change back skb->end, @@ -5584,18 +5599,18 @@ bool skb_try_coalesce(struct sk_buff *to, struct sk_buff *from, if (skb_cloned(to)) return false; - /* In general, avoid mixing slab allocated and page_pool allocated - * pages within the same SKB. However when @to is not pp_recycle and - * @from is cloned, we can transition frag pages from page_pool to - * reference counted. - * - * On the other hand, don't allow coalescing two pp_recycle SKBs if - * @from is cloned, in case the SKB is using page_pool fragment + /* In general, avoid mixing page_pool and non-page_pool allocated + * pages within the same SKB. Additionally avoid dealing with clones + * with page_pool pages, in case the SKB is using page_pool fragment * references (PP_FLAG_PAGE_FRAG). Since we only take full page * references for cloned SKBs at the moment that would result in * inconsistent reference counts. + * In theory we could take full references if @from is cloned and + * !@to->pp_recycle but its tricky (due to potential race with + * the clone disappearing) and rare, so not worth dealing with. */ - if (to->pp_recycle != (from->pp_recycle && !skb_cloned(from))) + if (to->pp_recycle != from->pp_recycle || + (from->pp_recycle && skb_cloned(from))) return false; if (len <= skb_tailroom(to)) { |