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commit b5b7d24ba1557dd745e0ef48e8f13a7a8a9a3865
Author: Fotis Panagiotopoulos <f.pa...@amco.gr>
AuthorDate: Mon Feb 13 19:15:37 2023 +0200
Improvements in CAN connections allocation.
---
.../nucleo-h743zi2/configs/socketcan/defconfig | 2 +-
net/can/Kconfig | 41 +++++++++++++++++++--
net/can/can_conn.c | 42 ++++++++++++++++------
3 files changed, 71 insertions(+), 14 deletions(-)
diff --git a/boards/arm/stm32h7/nucleo-h743zi2/configs/socketcan/defconfig
b/boards/arm/stm32h7/nucleo-h743zi2/configs/socketcan/defconfig
index 5101756e2a..798bc06cea 100644
--- a/boards/arm/stm32h7/nucleo-h743zi2/configs/socketcan/defconfig
+++ b/boards/arm/stm32h7/nucleo-h743zi2/configs/socketcan/defconfig
@@ -25,7 +25,7 @@ CONFIG_BOARD_LOOPSPERMSEC=43103
CONFIG_BUILTIN=y
CONFIG_CANUTILS_CANDUMP=y
CONFIG_CANUTILS_CANSEND=y
-CONFIG_CAN_CONNS=2
+CONFIG_CAN_PREALLOC_CONNS=2
CONFIG_DEBUG_ERROR=y
CONFIG_DEBUG_FEATURES=y
CONFIG_DEBUG_INFO=y
diff --git a/net/can/Kconfig b/net/can/Kconfig
index 10cffb0024..3f053e7f38 100644
--- a/net/can/Kconfig
+++ b/net/can/Kconfig
@@ -30,11 +30,46 @@ config NET_CAN_HAVE_ERRORS
bool
default n
-config CAN_CONNS
- int "Max number of CAN socket connections"
+config CAN_PREALLOC_CONNS
+ int "Preallocated CAN socket connections"
default 4
---help---
- Maximum number of CAN connections (all tasks).
+ Number of CAN connections (all tasks).
+
+ This number of connections will be pre-allocated during system
boot.
+ If dynamic connections allocation is enabled, more connections
may
+ be allocated at a later time, as the system needs them. Else
this
+ will be the maximum number of connections available to the
system
+ at all times.
+
+ Set to 0 to disable (and rely only on dynamic allocations).
+
+config CAN_ALLOC_CONNS
+ int "Dynamic CAN connections allocation"
+ default 0
+ ---help---
+ Dynamic memory allocations for CAN.
+
+ When set to 0 all dynamic allocations are disabled.
+
+ When set to 1 a new connection will be allocated every time,
+ and it will be free'd when no longer needed.
+
+ Setting this to 2 or more will allocate the connections in
+ batches (with batch size equal to this config). When a
+ connection is no longer needed, it will be returned to the
+ free connections pool, and it will never be deallocated!
+
+config CAN_MAX_CONNS
+ int "Maximum number of CAN connections"
+ default 0
+ depends on CAN_ALLOC_CONNS > 0
+ ---help---
+ If dynamic connections allocation is selected (CAN_ALLOC_CONNS
> 0)
+ this will limit the number of connections that can be allocated.
+
+ This is useful in case the system is under very heavy load (or
+ under attack), ensuring that the heap will not be exhausted.
config NET_CAN_EXTID
bool "Enable CAN extended IDs"
diff --git a/net/can/can_conn.c b/net/can/can_conn.c
index b12683427b..4310bc81bb 100644
--- a/net/can/can_conn.c
+++ b/net/can/can_conn.c
@@ -49,8 +49,8 @@
/* The array containing all NetLink connections. */
-#ifndef CONFIG_NET_ALLOC_CONNS
-static struct can_conn_s g_can_connections[CONFIG_CAN_CONNS];
+#if CONFIG_CAN_PREALLOC_CONNS > 0
+static struct can_conn_s g_can_connections[CONFIG_CAN_PREALLOC_CONNS];
#endif
/* A list of all free NetLink connections */
@@ -77,10 +77,10 @@ static dq_queue_t g_active_can_connections;
void can_initialize(void)
{
-#ifndef CONFIG_NET_ALLOC_CONNS
+#if CONFIG_CAN_PREALLOC_CONNS > 0
int i;
- for (i = 0; i < CONFIG_CAN_CONNS; i++)
+ for (i = 0; i < CONFIG_CAN_PREALLOC_CONNS; i++)
{
/* Mark the connection closed and move it to the free list */
@@ -101,20 +101,29 @@ void can_initialize(void)
FAR struct can_conn_s *can_alloc(void)
{
FAR struct can_conn_s *conn;
-#ifdef CONFIG_NET_ALLOC_CONNS
+#if CONFIG_CAN_ALLOC_CONNS > 0
int i;
#endif
/* The free list is protected by a a mutex. */
nxmutex_lock(&g_free_lock);
-#ifdef CONFIG_NET_ALLOC_CONNS
+#if CONFIG_CAN_ALLOC_CONNS > 0
if (dq_peek(&g_free_can_connections) == NULL)
{
- conn = kmm_zalloc(sizeof(*conn) * CONFIG_CAN_CONNS);
+#if CONFIG_CAN_MAX_CONNS > 0
+ if (dq_count(&g_active_can_connections) + CONFIG_CAN_ALLOC_CONNS
+ >= CONFIG_CAN_MAX_CONNS)
+ {
+ nxmutex_unlock(&g_free_lock);
+ return NULL;
+ }
+#endif
+
+ conn = kmm_zalloc(sizeof(*conn) * CONFIG_CAN_ALLOC_CONNS);
if (conn != NULL)
{
- for (i = 0; i < CONFIG_CAN_CONNS; i++)
+ for (i = 0; i < CONFIG_CAN_ALLOC_CONNS; i++)
{
dq_addlast(&conn[i].sconn.node, &g_free_can_connections);
}
@@ -177,9 +186,22 @@ void can_free(FAR struct can_conn_s *conn)
memset(conn, 0, sizeof(*conn));
- /* Free the connection */
+ /* If this is a preallocated or a batch allocated connection store it in
+ * the free connections list. Else free it.
+ */
+
+#if CONFIG_CAN_ALLOC_CONNS == 1
+ if (conn < g_can_connections || conn >= (g_can_connections +
+ CONFIG_CAN_PREALLOC_CONNS))
+ {
+ kmm_free(conn);
+ }
+ else
+#endif
+ {
+ dq_addlast(&conn->sconn.node, &g_free_can_connections);
+ }
- dq_addlast(&conn->sconn.node, &g_free_can_connections);
nxmutex_unlock(&g_free_lock);
}
