ipc: increase file descriptor maximum number

The TAP and XDP driver both are limited to only 8 queues because of the
small limit imposed by EAL.
Increase the limit now, since this release allows changing ABI.

Signed-off-by: Stephen Hemminger <[email protected]>
Acked-by: Chengwen Feng <[email protected]>
Acked-by: Morten Brørup <[email protected]>
Acked-by: Ferruh Yigit <[email protected]>

Author: shemminger

doc/guides/rel_notes/release_24_11.rst

@@ -127,6 +127,10 @@ ABI Changes
    Also, make sure to start the actual text at the margin.
    =======================================================
 
+* eal: The maximum number of file descriptors that can be passed to a secondary process
+  has been increased from 8 to 253 (which is the maximum possible with Unix domain socket).
+  This allows for more queues when using software devices such as TAP and XDP.
+
 
 Known Issues
 ------------

lib/eal/include/rte_eal.h

@@ -155,7 +155,7 @@ int rte_eal_primary_proc_alive(const char *config_file_path);
  */
 bool rte_mp_disable(void);
 
-#define RTE_MP_MAX_FD_NUM	8    /* The max amount of fds */
+#define RTE_MP_MAX_FD_NUM	253  /* The max amount of fds (see SCM_MAX_FD) */
 #define RTE_MP_MAX_NAME_LEN	64   /* The max length of action name */
 #define RTE_MP_MAX_PARAM_LEN	256  /* The max length of param */
 struct rte_mp_msg {