From 49e29ac2cb7278ca62bad6d3ca15dfdf817ce4af Mon Sep 17 00:00:00 2001 From: Hiroyuki Mikita Date: Wed, 18 May 2016 23:41:03 +0900 Subject: [PATCH] mbuf: decrease reference counter when detaching The rte_pktmbuf_detach() function should decrease refcnt on a direct buffer as stated in doc/guides/prog_guide/mbuf_lib.rst: "whenever the indirect buffer is detached, the reference counter on the direct buffer is decremented." Signed-off-by: Hiroyuki Mikita Acked-by: Olivier Matz --- app/test/test_mbuf.c | 4 ++++ doc/guides/rel_notes/release_16_07.rst | 6 ++++++ lib/librte_mbuf/rte_mbuf.h | 23 ++++++++++++----------- 3 files changed, 22 insertions(+), 11 deletions(-) diff --git a/app/test/test_mbuf.c b/app/test/test_mbuf.c index 98ff93afd2..8460db7be2 100644 --- a/app/test/test_mbuf.c +++ b/app/test/test_mbuf.c @@ -511,10 +511,14 @@ test_attach_from_different_pool(void) rte_pktmbuf_detach(clone); if (c_data != rte_pktmbuf_mtod(clone, char *)) GOTO_FAIL("clone was not detached properly\n"); + if (rte_mbuf_refcnt_read(m) != 2) + GOTO_FAIL("invalid refcnt in m\n"); rte_pktmbuf_detach(clone2); if (c_data2 != rte_pktmbuf_mtod(clone2, char *)) GOTO_FAIL("clone2 was not detached properly\n"); + if (rte_mbuf_refcnt_read(m) != 1) + GOTO_FAIL("invalid refcnt in m\n"); /* free the clones and the initial mbuf */ rte_pktmbuf_free(clone2); diff --git a/doc/guides/rel_notes/release_16_07.rst b/doc/guides/rel_notes/release_16_07.rst index 58c8ef9f87..a8c50c8989 100644 --- a/doc/guides/rel_notes/release_16_07.rst +++ b/doc/guides/rel_notes/release_16_07.rst @@ -69,6 +69,12 @@ Drivers Libraries ~~~~~~~~~ +* **mbuf: Fixed refcnt update when detaching.** + + Fix the ``rte_pktmbuf_detach()`` function to decrement the direct + mbuf's reference counter. The previous behavior was not to affect + the reference counter. It lead a memory leak of the direct mbuf. + Examples ~~~~~~~~ diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h index 7b92b88a84..48911a69a9 100644 --- a/lib/librte_mbuf/rte_mbuf.h +++ b/lib/librte_mbuf/rte_mbuf.h @@ -1412,6 +1412,8 @@ static inline int rte_pktmbuf_alloc_bulk(struct rte_mempool *pool, * * After attachment we refer the mbuf we attached as 'indirect', * while mbuf we attached to as 'direct'. + * The direct mbuf's reference counter is incremented. + * * Right now, not supported: * - attachment for already indirect mbuf (e.g. - mi has to be direct). * - mbuf we trying to attach (mi) is used by someone else @@ -1465,13 +1467,17 @@ static inline void rte_pktmbuf_attach(struct rte_mbuf *mi, struct rte_mbuf *m) * * - restore original mbuf address and length values. * - reset pktmbuf data and data_len to their default values. - * All other fields of the given packet mbuf will be left intact. + * - decrement the direct mbuf's reference counter. When the + * reference counter becomes 0, the direct mbuf is freed. + * + * All other fields of the given packet mbuf will be left intact. * * @param m * The indirect attached packet mbuf. */ static inline void rte_pktmbuf_detach(struct rte_mbuf *m) { + struct rte_mbuf *md = rte_mbuf_from_indirect(m); struct rte_mempool *mp = m->pool; uint32_t mbuf_size, buf_len, priv_size; @@ -1486,6 +1492,9 @@ static inline void rte_pktmbuf_detach(struct rte_mbuf *m) m->data_off = RTE_MIN(RTE_PKTMBUF_HEADROOM, (uint16_t)m->buf_len); m->data_len = 0; m->ol_flags = 0; + + if (rte_mbuf_refcnt_update(md, -1) == 0) + __rte_mbuf_raw_free(md); } static inline struct rte_mbuf* __attribute__((always_inline)) @@ -1494,17 +1503,9 @@ __rte_pktmbuf_prefree_seg(struct rte_mbuf *m) __rte_mbuf_sanity_check(m, 0); if (likely(rte_mbuf_refcnt_update(m, -1) == 0)) { - - /* if this is an indirect mbuf, then - * - detach mbuf - * - free attached mbuf segment - */ - if (RTE_MBUF_INDIRECT(m)) { - struct rte_mbuf *md = rte_mbuf_from_indirect(m); + /* if this is an indirect mbuf, it is detached. */ + if (RTE_MBUF_INDIRECT(m)) rte_pktmbuf_detach(m); - if (rte_mbuf_refcnt_update(md, -1) == 0) - __rte_mbuf_raw_free(md); - } return m; } return NULL; -- 2.20.1