diff options
Diffstat (limited to 'net/core/skbuff.c')
| -rw-r--r-- | net/core/skbuff.c | 35 |
1 files changed, 23 insertions, 12 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 7b3df0d518ab..829d013745ab 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -360,18 +360,29 @@ refill: goto end; } nc->frag.size = PAGE_SIZE << order; -recycle: - atomic_set(&nc->frag.page->_count, NETDEV_PAGECNT_MAX_BIAS); + /* Even if we own the page, we do not use atomic_set(). + * This would break get_page_unless_zero() users. + */ + atomic_add(NETDEV_PAGECNT_MAX_BIAS - 1, + &nc->frag.page->_count); nc->pagecnt_bias = NETDEV_PAGECNT_MAX_BIAS; nc->frag.offset = 0; } if (nc->frag.offset + fragsz > nc->frag.size) { - /* avoid unnecessary locked operations if possible */ - if ((atomic_read(&nc->frag.page->_count) == nc->pagecnt_bias) || - atomic_sub_and_test(nc->pagecnt_bias, &nc->frag.page->_count)) - goto recycle; - goto refill; + if (atomic_read(&nc->frag.page->_count) != nc->pagecnt_bias) { + if (!atomic_sub_and_test(nc->pagecnt_bias, + &nc->frag.page->_count)) + goto refill; + /* OK, page count is 0, we can safely set it */ + atomic_set(&nc->frag.page->_count, + NETDEV_PAGECNT_MAX_BIAS); + } else { + atomic_add(NETDEV_PAGECNT_MAX_BIAS - nc->pagecnt_bias, + &nc->frag.page->_count); + } + nc->pagecnt_bias = NETDEV_PAGECNT_MAX_BIAS; + nc->frag.offset = 0; } data = page_address(nc->frag.page) + nc->frag.offset; @@ -4126,11 +4137,11 @@ EXPORT_SYMBOL(skb_vlan_untag); /** * alloc_skb_with_frags - allocate skb with page frags * - * header_len: size of linear part - * data_len: needed length in frags - * max_page_order: max page order desired. - * errcode: pointer to error code if any - * gfp_mask: allocation mask + * @header_len: size of linear part + * @data_len: needed length in frags + * @max_page_order: max page order desired. + * @errcode: pointer to error code if any + * @gfp_mask: allocation mask * * This can be used to allocate a paged skb, given a maximal order for frags. */ |