[dpdk-stable] [PATCH dpdk-dev v2] common/mlx5: fix possible building error

[Tonghao Zhang]

On Thu, Mar 5, 2020 at 12:03 AM Matan Azrad <matan at mellanox.com> wrote:
>
>
>
> From: Tonghao Zhang
> > On Wed, Mar 4, 2020 at 10:25 PM Matan Azrad <matan at mellanox.com>
> > wrote:
> > >
> > >
> > >
> > > From: Tonghao Zhang
> > > > On Tue, Mar 3, 2020 at 3:15 PM Matan Azrad <matan at mellanox.com>
> > wrote:
> > > > >
> > > > >
> > > > > Hi
> > > > >
> > > > > From: xiangxia.m.yue at gmail.com
> > > > > > From: Tonghao Zhang <xiangxia.m.yue at gmail.com>
> > > > > >
> > > > > > When setting the CONFIG_RTE_BUILD_SHARED_LIB to y, and build
> > the
> > > > > > mlx5 pmd, there is a building error.
> > > > > > To fix it, add RTE_IBVERBS_LINK_DLOPEN to include relative codes.
> > > > > >
> > > > > > > mlx5_common.o: In function `mlx5_glue_init':
> > > > > > > drivers/common/mlx5/mlx5_common.c:324: undefined reference
> > to
> > > > > > `dlclose'
> > > > > >
> > > > > > Fixes: 7b4f1e6bd367 ("common/mlx5: introduce common library")
> > > > > > Cc: stable at dpdk.org
> > > > > >
> > > > > > Signed-off-by: Tonghao Zhang <xiangxia.m.yue at gmail.com>
> > > > > > Tested-by: Ali Alnubani <alialnu at mellanox.com>
> > > > >
> > > > > The title should point to the root cause - not to the results.
> > > > >
> > > > > Something like:
> > > > >
> > > > > common/mlx5: fix dynamic loading reference
> > > > >
> > > > > >  drivers/common/mlx5/mlx5_common.c | 5 +++--
> > > > > >  1 file changed, 3 insertions(+), 2 deletions(-)
> > > > > >
> > > > > > diff --git a/drivers/common/mlx5/mlx5_common.c
> > > > > > b/drivers/common/mlx5/mlx5_common.c
> > > > > > index 610fb48..570a3f4 100644
> > > > > > --- a/drivers/common/mlx5/mlx5_common.c
> > > > > > +++ b/drivers/common/mlx5/mlx5_common.c
> > > > > > @@ -209,8 +209,6 @@ enum mlx5_class
> > > > > >   */
> > > > > >  RTE_INIT_PRIO(mlx5_glue_init, CLASS)  {
> > > > > > -     void *handle = NULL;
> > > > > > -
> > > > > >       /* Initialize common log type. */
> > > > > >       mlx5_common_logtype = rte_log_register("pmd.common.mlx5");
> > > > > >       if (mlx5_common_logtype >= 0) @@ -249,6 +247,7 @@ enum
> > > > > > mlx5_class
> > > > > >                mlx5_glue_path(glue_path, sizeof(glue_path)) : ""),
> > > > > >       };
> > > > > >       unsigned int i = 0;
> > > > > > +     void *handle = NULL;
> > > > > >       void **sym;
> > > > > >       const char *dlmsg;
> > > > > >
> > > > > > @@ -320,8 +319,10 @@ enum mlx5_class
> > > > > >       mlx5_glue->fork_init();
> > > > > >       return;
> > > > > >  glue_error:
> > > > > > +#ifdef RTE_IBVERBS_LINK_DLOPEN
> > > > > >       if (handle)
> > > > > >               dlclose(handle);
> > > > > > +#endif
> > > > >
> > > > >
> > > > > What's about " #include <dlfcn.h> " Is it compiled for you?
> > > > Yes, still building fail.
> > > > > If so, why dlclose is not known on your setup?
> > > > When I fixed it, I found the codes in mlx5_glue_init, use the
> > > > RTE_IBVERBS_LINK_DLOPEN.
> > > > but dlclose is not included in it. I think we should add
> > > > RTE_IBVERBS_LINK_DLOPEN to fix the building fail.
> > >
> > > I agree, but looks like the include should be in the define area too. No?
> > No, the "dlfcn.h" in dpdk is not included in define area at all.
> >
> > [root at localhost dpdk-next-net]# grep -rwin "dlfcn.h"
> > lib/librte_eal/common/eal_common_options.c:17:#include <dlfcn.h>
> > drivers/net/ark/ark_ethdev.c:7:#include <dlfcn.h>
> > drivers/net/mlx4/mlx4.c:11:#include <dlfcn.h>
> > drivers/common/mlx5/mlx5_common.c:5:#include <dlfcn.h>
> > examples/performance-thread/pthread_shim/pthread_shim.c:10:#include
> > <dlfcn.h>
> >
> > and other codes should be in define area, but not:
> > drivers/net/ark/ark_ethdev.c:177
> > lib/librte_eal/common/eal_common_options.c:306
> > drivers/common/mlx5/mlx5_common.c:325(this patch fix)
> >
>
>
> So, Is it compiled well to include it while its lib is not loaded?
Review the codes again, RTE_IBVERBS_LINK_DLOPEN is only used for
mlx4/mlx5. Other codes is unnecessary included in
RTE_IBVERBS_LINK_DLOPEN define.

v3 is shown as below, and tested:
https://travis-ci.com/ovn-open-virtual-networks/dpdk-next-net/builds/151882661

diff --git a/drivers/common/mlx5/mlx5_common.c
b/drivers/common/mlx5/mlx5_common.c
index 610fb48..9ea56f2 100644
--- a/drivers/common/mlx5/mlx5_common.c
+++ b/drivers/common/mlx5/mlx5_common.c
@@ -2,10 +2,12 @@
  * Copyright 2019 Mellanox Technologies, Ltd
  */

-#include <dlfcn.h>
 #include <unistd.h>
 #include <string.h>
 #include <stdio.h>
+#ifdef RTE_IBVERBS_LINK_DLOPEN
+#include <dlfcn.h>
+#endif

 #include <rte_errno.h>

@@ -209,8 +211,6 @@ enum mlx5_class
  */
 RTE_INIT_PRIO(mlx5_glue_init, CLASS)
 {
-       void *handle = NULL;
-
        /* Initialize common log type. */
        mlx5_common_logtype = rte_log_register("pmd.common.mlx5");
        if (mlx5_common_logtype >= 0)
@@ -233,6 +233,8 @@ enum mlx5_class
        /* The glue initialization was done earlier by mlx5 common library. */
 #ifdef RTE_IBVERBS_LINK_DLOPEN
        char glue_path[sizeof(RTE_EAL_PMD_PATH) - 1 + sizeof("-glue")];
+       void *handle = NULL;
+
        const char *path[] = {
                /*
                 * A basic security check is necessary before trusting
@@ -320,8 +322,10 @@ enum mlx5_class
        mlx5_glue->fork_init();
        return;
 glue_error:
+#ifdef RTE_IBVERBS_LINK_DLOPEN
        if (handle)
                dlclose(handle);
+#endif
        DRV_LOG(WARNING, "Cannot initialize MLX5 common due to missing"
                " run-time dependency on rdma-core libraries (libibverbs,"
                " libmlx5)");
diff --git a/drivers/net/mlx4/mlx4.c b/drivers/net/mlx4/mlx4.c
index a1dd658..8e29878 100644
--- a/drivers/net/mlx4/mlx4.c
+++ b/drivers/net/mlx4/mlx4.c
@@ -8,7 +8,6 @@
  * mlx4 driver initialization.
  */

-#include <dlfcn.h>
 #include <errno.h>
 #include <inttypes.h>
 #include <stddef.h>
@@ -18,6 +17,9 @@
 #include <string.h>
 #include <sys/mman.h>
 #include <unistd.h>
+#ifdef RTE_IBVERBS_LINK_DLOPEN
+#include <dlfcn.h>
+#endif

 /* Verbs headers do not support -pedantic. */
 #ifdef PEDANTIC

> > > > >
> > > > >
> > > > > >       DRV_LOG(WARNING, "Cannot initialize MLX5 common due to
> > > > > > missing"
> > > > > >               " run-time dependency on rdma-core libraries (libibverbs,"
> > > > > >               " libmlx5)");
> > > > > > --
> > > > > > 1.8.3.1
> > > > >
> > > >
> > > >
> > > > --
> > > > Thanks,
> > > > Tonghao
> >
> >
> >
> > --
> > Thanks,
> > Tonghao



-- 
Thanks,
Tonghao