mempool: fix mempool virt populate with small chunks

To populate a mempool with a virtual area, the mempool code calls
rte_mempool_populate_iova() for each iova-contiguous area. It happens
(rarely) that this area is too small to store one object. In this case,
rte_mempool_populate_iova() returns an error, which is forwarded by
rte_mempool_populate_virt().

This case should not throw an error in
rte_mempool_populate_virt(). Instead, the area that is too small should
just be ignored.

To fix this issue, change the return value of
rte_mempool_populate_iova() to -ENOBUFS when no object can be populated,
so it can be ignored by the caller. As this would be an API change, add
a compat wrapper to keep the current API unchanged. The wrapper will be
removed for 20.11.

Fixes: 354788b60cfd ("mempool: allow populating with unaligned virtual area")
Cc: stable@dpdk.org
Signed-off-by: Olivier Matz <olivier.matz@6wind.com>

diff --git a/doc/guides/rel_notes/deprecation.rst b/doc/guides/rel_notes/deprecation.rst
index afa94b4..b6e89d9 100644 (file)
--- a/doc/guides/rel_notes/deprecation.rst
+++ b/doc/guides/rel_notes/deprecation.rst
@@ -86,3 +86,7 @@ Deprecation Notices
   to set new power environment if power environment was already initialized.
   In this case the function will return -1 unless the environment is unset first
   (using ``rte_power_unset_env``). Other function usage scenarios will not change.
+
+* mempool: starting from v20.11, rte_mempool_populate_iova() will
+  return -ENOBUFS instead of -EINVAL when there is not enough room to
+  store one object.

diff --git a/lib/librte_mempool/meson.build b/lib/librte_mempool/meson.build
index f8710b6..4fe267c 100644 (file)
--- a/lib/librte_mempool/meson.build
+++ b/lib/librte_mempool/meson.build
@@ -18,3 +18,4 @@ deps += ['ring']
 
 # memseg walk is not yet part of stable API
 allow_experimental_apis = true
+use_function_versioning = true

diff --git a/lib/librte_mempool/rte_mempool.c b/lib/librte_mempool/rte_mempool.c
index 78d8eb9..ff95f41 100644 (file)
--- a/lib/librte_mempool/rte_mempool.c
+++ b/lib/librte_mempool/rte_mempool.c
@@ -31,6 +31,7 @@
 #include <rte_string_fns.h>
 #include <rte_spinlock.h>
 #include <rte_tailq.h>
+#include <rte_function_versioning.h>
 
 #include "rte_mempool.h"
 
@@ -293,12 +294,17 @@ mempool_ops_alloc_once(struct rte_mempool *mp)
        return 0;
 }
 
+int
+rte_mempool_populate_iova_v20_0_1(struct rte_mempool *mp, char *vaddr,
+       rte_iova_t iova, size_t len, rte_mempool_memchunk_free_cb_t *free_cb,
+       void *opaque);
+
 /* Add objects in the pool, using a physically contiguous memory
  * zone. Return the number of objects added, or a negative value
  * on error.
  */
 int
-rte_mempool_populate_iova(struct rte_mempool *mp, char *vaddr,
+rte_mempool_populate_iova_v20_0_1(struct rte_mempool *mp, char *vaddr,
        rte_iova_t iova, size_t len, rte_mempool_memchunk_free_cb_t *free_cb,
        void *opaque)
 {
@@ -332,7 +338,7 @@ rte_mempool_populate_iova(struct rte_mempool *mp, char *vaddr,
                off = RTE_PTR_ALIGN_CEIL(vaddr, RTE_MEMPOOL_ALIGN) - vaddr;
 
        if (off > len) {
-               ret = -EINVAL;
+               ret = -ENOBUFS;
                goto fail;
        }
 
@@ -343,7 +349,7 @@ rte_mempool_populate_iova(struct rte_mempool *mp, char *vaddr,
 
        /* not enough room to store one object */
        if (i == 0) {
-               ret = -EINVAL;
+               ret = -ENOBUFS;
                goto fail;
        }
 
@@ -355,6 +361,33 @@ fail:
        rte_free(memhdr);
        return ret;
 }
+BIND_DEFAULT_SYMBOL(rte_mempool_populate_iova, _v20_0_1, 20.0.1);
+MAP_STATIC_SYMBOL(
+       int rte_mempool_populate_iova(struct rte_mempool *mp, char *vaddr,
+                               rte_iova_t iova, size_t len,
+                               rte_mempool_memchunk_free_cb_t *free_cb,
+                               void *opaque),
+       rte_mempool_populate_iova_v20_0_1);
+
+int
+rte_mempool_populate_iova_v20_0(struct rte_mempool *mp, char *vaddr,
+       rte_iova_t iova, size_t len, rte_mempool_memchunk_free_cb_t *free_cb,
+       void *opaque);
+int
+rte_mempool_populate_iova_v20_0(struct rte_mempool *mp, char *vaddr,
+       rte_iova_t iova, size_t len, rte_mempool_memchunk_free_cb_t *free_cb,
+       void *opaque)
+{
+       int ret;
+
+       ret = rte_mempool_populate_iova_v20_0_1(mp, vaddr, iova, len, free_cb,
+                                       opaque);
+       if (ret == -ENOBUFS)
+               ret = -EINVAL;
+
+       return ret;
+}
+VERSION_SYMBOL(rte_mempool_populate_iova, _v20_0, 20.0);
 
 static rte_iova_t
 get_iova(void *addr)
@@ -381,6 +414,13 @@ rte_mempool_populate_virt(struct rte_mempool *mp, char *addr,
        size_t off, phys_len;
        int ret, cnt = 0;
 
+       /* call alloc_once() in advance, it avoids a misinterpretation
+        * of -ENOBUFS when delegated to rte_mempool_populate_iova().
+        */
+       ret = mempool_ops_alloc_once(mp);
+       if (ret != 0)
+               return ret;
+
        if (mp->flags & MEMPOOL_F_NO_IOVA_CONTIG)
                return rte_mempool_populate_iova(mp, addr, RTE_BAD_IOVA,
                        len, free_cb, opaque);
@@ -406,8 +446,10 @@ rte_mempool_populate_virt(struct rte_mempool *mp, char *addr,
                                break;
                }
 
-               ret = rte_mempool_populate_iova(mp, addr + off, iova,
+               ret = rte_mempool_populate_iova_v20_0_1(mp, addr + off, iova,
                        phys_len, free_cb, opaque);
+               if (ret == -ENOBUFS)
+                       continue;
                if (ret < 0)
                        goto fail;
                /* no need to call the free callback for next chunks */

diff --git a/lib/librte_mempool/rte_mempool.h b/lib/librte_mempool/rte_mempool.h
index f81152a..c08bb44 100644 (file)
--- a/lib/librte_mempool/rte_mempool.h
+++ b/lib/librte_mempool/rte_mempool.h
@@ -1108,7 +1108,10 @@ rte_mempool_free(struct rte_mempool *mp);
  * @return
  *   The number of objects added on success.
  *   On error, the chunk is not added in the memory list of the
- *   mempool and a negative errno is returned.
+ *   mempool and a negative errno is returned:
+ *   (-ENOBUFS): not enough room in chunk for one object.
+ *   (-ENOSPC): mempool is already populated.
+ *   (-ENOMEM): allocation failure.
  */
 int rte_mempool_populate_iova(struct rte_mempool *mp, char *vaddr,
        rte_iova_t iova, size_t len, rte_mempool_memchunk_free_cb_t *free_cb,

diff --git a/lib/librte_mempool/rte_mempool_version.map b/lib/librte_mempool/rte_mempool_version.map
index d002dfc..402e731 100644 (file)
--- a/lib/librte_mempool/rte_mempool_version.map
+++ b/lib/librte_mempool/rte_mempool_version.map
@@ -35,6 +35,12 @@ DPDK_20.0 {
        local: *;
 };
 
+DPDK_20.0.1 {
+       global:
+
+       rte_mempool_populate_iova;
+} DPDK_20.0;
+
 EXPERIMENTAL {
        global: