mempool: add structure for object headers

Each object stored in mempools are prefixed by a header, allowing for
instance to retrieve the mempool pointer from the object. When debug is
enabled, a cookie is also added in this header that helps to detect
corruptions and double-frees.

Introduce a structure that materializes the content of this header,
and will simplify future patches adding things in this header.

Signed-off-by: Olivier Matz <olivier.matz@6wind.com>

diff --git a/lib/librte_mempool/rte_mempool.c b/lib/librte_mempool/rte_mempool.c
index 190cfd9..b2d8700 100644 (file)
--- a/lib/librte_mempool/rte_mempool.c
+++ b/lib/librte_mempool/rte_mempool.c
@@ -130,16 +130,16 @@ static void
 mempool_add_elem(struct rte_mempool *mp, void *obj, uint32_t obj_idx,
        rte_mempool_obj_ctor_t *obj_init, void *obj_init_arg)
 {
-       struct rte_mempool **mpp;
+       struct rte_mempool_objhdr *hdr;
 
        obj = (char *)obj + mp->header_size;
 
        /* set mempool ptr in header */
-       mpp = __mempool_from_obj(obj);
-       *mpp = mp;
+       hdr = (struct rte_mempool_objhdr *)((char *)obj - sizeof(*hdr));
+       hdr->mp = mp;
 
 #ifdef RTE_LIBRTE_MEMPOOL_DEBUG
-       __mempool_write_header_cookie(obj, 1);
+       hdr->cookie = RTE_MEMPOOL_HEADER_COOKIE2;
        __mempool_write_trailer_cookie(obj);
 #endif
        /* call the initializer */

diff --git a/lib/librte_mempool/rte_mempool.h b/lib/librte_mempool/rte_mempool.h
index bc2bae0..b047810 100644 (file)
--- a/lib/librte_mempool/rte_mempool.h
+++ b/lib/librte_mempool/rte_mempool.h
@@ -139,6 +139,21 @@ struct rte_mempool_objsz {
 /** Mempool over one chunk of physically continuous memory */
 #define        MEMPOOL_PG_NUM_DEFAULT  1
 
+/**
+ * Mempool object header structure
+ *
+ * Each object stored in mempools are prefixed by this header structure,
+ * it allows to retrieve the mempool pointer from the object. When debug
+ * is enabled, a cookie is also added in this structure preventing
+ * corruptions and double-frees.
+ */
+struct rte_mempool_objhdr {
+       struct rte_mempool *mp;          /**< The mempool owning the object. */
+#ifdef RTE_LIBRTE_MEMPOOL_DEBUG
+       uint64_t cookie;                 /**< Debug cookie. */
+#endif
+};
+
 /**
  * The RTE mempool structure.
  */
@@ -227,24 +242,11 @@ struct rte_mempool {
        ((mp)->pg_num == MEMPOOL_PG_NUM_DEFAULT && \
        (mp)->phys_addr == (mp)->elt_pa[0])
 
-/**
- * @internal Get a pointer to a mempool pointer in the object header.
- * @param obj
- *   Pointer to object.
- * @return
- *   The pointer to the mempool from which the object was allocated.
- */
-static inline struct rte_mempool **__mempool_from_obj(void *obj)
+/* return the header of a mempool object (internal) */
+static inline struct rte_mempool_objhdr *__mempool_get_header(void *obj)
 {
-       struct rte_mempool **mpp;
-       unsigned off;
-
-       off = sizeof(struct rte_mempool *);
-#ifdef RTE_LIBRTE_MEMPOOL_DEBUG
-       off += sizeof(uint64_t);
-#endif
-       mpp = (struct rte_mempool **)((char *)obj - off);
-       return mpp;
+       return (struct rte_mempool_objhdr *)((char *)obj -
+               sizeof(struct rte_mempool_objhdr));
 }
 
 /**
@@ -256,36 +258,18 @@ static inline struct rte_mempool **__mempool_from_obj(void *obj)
  * @return
  *   A pointer to the mempool structure.
  */
-static inline const struct rte_mempool *rte_mempool_from_obj(void *obj)
+static inline struct rte_mempool *rte_mempool_from_obj(void *obj)
 {
-       struct rte_mempool * const *mpp;
-       mpp = __mempool_from_obj(obj);
-       return *mpp;
+       struct rte_mempool_objhdr *hdr = __mempool_get_header(obj);
+       return hdr->mp;
 }
 
 #ifdef RTE_LIBRTE_MEMPOOL_DEBUG
-/* get header cookie value */
-static inline uint64_t __mempool_read_header_cookie(const void *obj)
-{
-       return *(const uint64_t *)((const char *)obj - sizeof(uint64_t));
-}
-
 /* get trailer cookie value */
 static inline uint64_t __mempool_read_trailer_cookie(void *obj)
 {
-       struct rte_mempool **mpp = __mempool_from_obj(obj);
-       return *(uint64_t *)((char *)obj + (*mpp)->elt_size);
-}
-
-/* write header cookie value */
-static inline void __mempool_write_header_cookie(void *obj, int free)
-{
-       uint64_t *cookie_p;
-       cookie_p = (uint64_t *)((char *)obj - sizeof(uint64_t));
-       if (free == 0)
-               *cookie_p = RTE_MEMPOOL_HEADER_COOKIE1;
-       else
-               *cookie_p = RTE_MEMPOOL_HEADER_COOKIE2;
+       struct rte_mempool *mp = rte_mempool_from_obj(obj);
+       return *(uint64_t *)((char *)obj + mp->elt_size);
 
 }
 
@@ -293,8 +277,8 @@ static inline void __mempool_write_header_cookie(void *obj, int free)
 static inline void __mempool_write_trailer_cookie(void *obj)
 {
        uint64_t *cookie_p;
-       struct rte_mempool **mpp = __mempool_from_obj(obj);
-       cookie_p = (uint64_t *)((char *)obj + (*mpp)->elt_size);
+       struct rte_mempool *mp = rte_mempool_from_obj(obj);
+       cookie_p = (uint64_t *)((char *)obj + mp->elt_size);
        *cookie_p = RTE_MEMPOOL_TRAILER_COOKIE;
 }
 #endif /* RTE_LIBRTE_MEMPOOL_DEBUG */
@@ -321,6 +305,7 @@ static inline void __mempool_check_cookies(const struct rte_mempool *mp,
                                           void * const *obj_table_const,
                                           unsigned n, int free)
 {
+       struct rte_mempool_objhdr *hdr;
        uint64_t cookie;
        void *tmp;
        void *obj;
@@ -338,7 +323,8 @@ static inline void __mempool_check_cookies(const struct rte_mempool *mp,
                        rte_panic("MEMPOOL: object is owned by another "
                                  "mempool\n");
 
-               cookie = __mempool_read_header_cookie(obj);
+               hdr = __mempool_get_header(obj);
+               cookie = hdr->cookie;
 
                if (free == 0) {
                        if (cookie != RTE_MEMPOOL_HEADER_COOKIE1) {
@@ -348,7 +334,7 @@ static inline void __mempool_check_cookies(const struct rte_mempool *mp,
                                        obj, (const void *) mp, cookie);
                                rte_panic("MEMPOOL: bad header cookie (put)\n");
                        }
-                       __mempool_write_header_cookie(obj, 1);
+                       hdr->cookie = RTE_MEMPOOL_HEADER_COOKIE2;
                }
                else if (free == 1) {
                        if (cookie != RTE_MEMPOOL_HEADER_COOKIE2) {
@@ -358,7 +344,7 @@ static inline void __mempool_check_cookies(const struct rte_mempool *mp,
                                        obj, (const void *) mp, cookie);
                                rte_panic("MEMPOOL: bad header cookie (get)\n");
                        }
-                       __mempool_write_header_cookie(obj, 0);
+                       hdr->cookie = RTE_MEMPOOL_HEADER_COOKIE1;
                }
                else if (free == 2) {
                        if (cookie != RTE_MEMPOOL_HEADER_COOKIE1 &&