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mbuf: decrease reference counter when detaching

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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 <h.mikita89@gmail.com>
Acked-by: Olivier Matz <olivier.matz@6wind.com>
This commit is contained in:
Hiroyuki Mikita 2016-05-18 23:41:03 +09:00 committed by Thomas Monjalon
parent 661d97ba0b
commit 49e29ac2cb
3 changed files with 22 additions and 11 deletions
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4
app/test/test_mbuf.c
View File

@ -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);

6
doc/guides/rel_notes/release_16_07.rst
View File

@ -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
~~~~~~~~

23
lib/librte_mbuf/rte_mbuf.h
View File

@ -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;