net/mlx: add static ibverbs linkage with meson

The libibverbs (and libmlx4/5) can be statically embedded
in the shared PMD library, or in the application with the static PMD.
It was supported with make build system in
commit 2c0dd7b69f ("config: add static linkage of mlx dependency").

The same feature is enabled with meson when using pkg-config
(i.e. only if the call to dependency() is successful).
The fallback method for searching library with cc.find_library()
is not supported because the dependencies of the found library
would not be linked (no such info in .a file unlike .so).

The main difference, in meson build system, is the generated .pc file
giving arguments to link DPDK with the application.
Unfortunately the .pc file will not keep memory of the static linkage
option for libibverbs.

Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>

doc/guides/nics/mlx4.rst

@@ -92,6 +92,10 @@ These options can be modified in the ``.config`` file.
   adds additional run-time checks and debugging messages at the cost of
   lower performance.
 
+This option is available in meson:
+
+- ``ibverbs_link`` can be ``static``, ``shared``, or ``dlopen``.
+
 Environment variables
 ~~~~~~~~~~~~~~~~~~~~~
 

doc/guides/nics/mlx5.rst

@@ -275,6 +275,10 @@ These options can be modified in the ``.config`` file.
    64. Default armv8a configuration of make build and meson build set it to 128
    then brings performance degradation.
 
+This option is available in meson:
+
+- ``ibverbs_link`` can be ``static``, ``shared``, or ``dlopen``.
+
 Environment variables
 ~~~~~~~~~~~~~~~~~~~~~
 

drivers/common/mlx5/meson.build

@@ -7,6 +7,7 @@ if not is_linux
 	subdir_done()
 endif
 
+static_ibverbs = (get_option('ibverbs_link') == 'static')
 pmd_dlopen = (get_option('ibverbs_link') == 'dlopen')
 LIB_GLUE_BASE = 'librte_pmd_mlx5_glue.so'
 LIB_GLUE_VERSION = '20.02.0'
@@ -22,8 +23,8 @@ endif
 libnames = [ 'mlx5', 'ibverbs' ]
 libs = []
 foreach libname:libnames
-	lib = dependency('lib' + libname, required:false)
+	lib = dependency('lib' + libname, static:static_ibverbs, required:false)
-	if not lib.found()
+	if not lib.found() and not static_ibverbs
 		lib = cc.find_library(libname, required:false)
 	endif
 	if lib.found()

drivers/net/mlx4/meson.build

@@ -8,6 +8,7 @@ if not is_linux
 	subdir_done()
 endif
 
+static_ibverbs = (get_option('ibverbs_link') == 'static')
 pmd_dlopen = (get_option('ibverbs_link') == 'dlopen')
 LIB_GLUE_BASE = 'librte_pmd_mlx4_glue.so'
 LIB_GLUE_VERSION = '18.02.0'
@@ -23,8 +24,8 @@ endif
 libnames = [ 'mlx4', 'ibverbs' ]
 libs = []
 foreach libname:libnames
-	lib = dependency('lib' + libname, required:false)
+	lib = dependency('lib' + libname, static:static_ibverbs, required:false)
-	if not lib.found()
+	if not lib.found() and not static_ibverbs
 		lib = cc.find_library(libname, required:false)
 	endif
 	if lib.found()

meson_options.txt

@@ -14,8 +14,8 @@ option('examples', type: 'string', value: '',
 	description: 'Comma-separated list of examples to build by default')
 option('flexran_sdk', type: 'string', value: '',
 	description: 'Path to FlexRAN SDK optional Libraries for BBDEV device')
-option('ibverbs_link', type: 'combo', choices : ['shared', 'dlopen'], value: 'shared',
+option('ibverbs_link', type: 'combo', choices : ['static', 'shared', 'dlopen'], value: 'shared',
-	description: 'Linkage method (shared/dlopen) for Mellanox PMDs with ibverbs dependencies.')
+	description: 'Linkage method (static/shared/dlopen) for Mellanox PMDs with ibverbs dependencies.')
 option('include_subdir_arch', type: 'string', value: '',
 	description: 'subdirectory where to install arch-dependent headers')
 option('kernel_dir', type: 'string', value: '',