mem: fix segment fd API error code for external segment

Segment fd API does not support getting segment fd's from
externally allocated memory, so return proper error code
on any attempts to do so. This changes API behavior, so
document the change as well.

Fixes: 5282bb1c3695 ("mem: allow memseg lists to be marked as external")
Cc: stable@dpdk.org
Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
Acked-by: Tiwei Bie <tiwei.bie@intel.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

diff --git a/doc/guides/rel_notes/release_19_02.rst b/doc/guides/rel_notes/release_19_02.rst
index c1fa884..63e84fe 100644 (file)
--- a/doc/guides/rel_notes/release_19_02.rst
+++ b/doc/guides/rel_notes/release_19_02.rst
@@ -109,6 +109,11 @@ API Changes
    Also, make sure to start the actual text at the margin.
    =========================================================
 
+* eal: Segment fd API on Linux now sets error code to ``ENOTSUP`` in more cases
+  where segment fd API is not expected to be supported:
+
+  - On attempt to get segment fd for an externally allocated memory segment
+
 * pdump: The ``rte_pdump_set_socket_dir()``, the parameter ``path`` of
   ``rte_pdump_init()`` and enum ``rte_pdump_socktype`` were deprecated
   since 18.05 and are removed in this release.

diff --git a/lib/librte_eal/common/eal_common_memory.c b/lib/librte_eal/common/eal_common_memory.c
index 051159f..c9da69b 100644 (file)
--- a/lib/librte_eal/common/eal_common_memory.c
+++ b/lib/librte_eal/common/eal_common_memory.c
@@ -705,6 +705,12 @@ rte_memseg_get_fd_thread_unsafe(const struct rte_memseg *ms)
                return -1;
        }
 
+       /* segment fd API is not supported for external segments */
+       if (msl->external) {
+               rte_errno = ENOTSUP;
+               return -1;
+       }
+
        ret = eal_memalloc_get_seg_fd(msl_idx, seg_idx);
        if (ret < 0) {
                rte_errno = -ret;
@@ -755,6 +761,12 @@ rte_memseg_get_fd_offset_thread_unsafe(const struct rte_memseg *ms,
                return -1;
        }
 
+       /* segment fd API is not supported for external segments */
+       if (msl->external) {
+               rte_errno = ENOTSUP;
+               return -1;
+       }
+
        ret = eal_memalloc_get_seg_fd_offset(msl_idx, seg_idx, offset);
        if (ret < 0) {
                rte_errno = -ret;