caif: Add ref-count to framing layer
Introduce Per-cpu reference for lower part of CAIF Stack.
Before freeing payload is disabled, synchronize_rcu() is called,
and then ref-count verified to be zero.
Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/caif/cffrml.h b/include/net/caif/cffrml.h
index 4f126d7..afac1a4 100644
--- a/include/net/caif/cffrml.h
+++ b/include/net/caif/cffrml.h
@@ -7,12 +7,15 @@
#ifndef CFFRML_H_
#define CFFRML_H_
#include <net/caif/caif_layer.h>
+#include <linux/netdevice.h>
struct cffrml;
-struct cflayer *cffrml_create(u16 phyid, bool DoFCS);
+struct cflayer *cffrml_create(u16 phyid, bool use_fcs);
+void cffrml_free(struct cflayer *layr);
void cffrml_set_uplayer(struct cflayer *this, struct cflayer *up);
void cffrml_set_dnlayer(struct cflayer *this, struct cflayer *dn);
void cffrml_put(struct cflayer *layr);
void cffrml_hold(struct cflayer *layr);
+int cffrml_refcnt_read(struct cflayer *layr);
#endif /* CFFRML_H_ */
diff --git a/net/caif/cfcnfg.c b/net/caif/cfcnfg.c
index 7892cc0..3f4f31f 100644
--- a/net/caif/cfcnfg.c
+++ b/net/caif/cfcnfg.c
@@ -519,6 +519,13 @@
caif_assert(phy_layer->id == phyid);
caif_assert(phyinfo->frm_layer->id == phyid);
+ /* Fail if reference count is not zero */
+ if (cffrml_refcnt_read(phyinfo->frm_layer) != 0) {
+ pr_info("Wait for device inuse\n");
+ mutex_unlock(&cnfg->lock);
+ return -EAGAIN;
+ }
+
list_del_rcu(&phyinfo->node);
synchronize_rcu();
@@ -537,7 +544,7 @@
if (phyinfo->phy_layer != frml_dn)
kfree(frml_dn);
- kfree(frml);
+ cffrml_free(frml);
kfree(phyinfo);
mutex_unlock(&cnfg->lock);
diff --git a/net/caif/cffrml.c b/net/caif/cffrml.c
index f4b8892..4f4f756 100644
--- a/net/caif/cffrml.c
+++ b/net/caif/cffrml.c
@@ -12,6 +12,7 @@
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/crc-ccitt.h>
+#include <linux/netdevice.h>
#include <net/caif/caif_layer.h>
#include <net/caif/cfpkt.h>
#include <net/caif/cffrml.h>
@@ -21,6 +22,7 @@
struct cffrml {
struct cflayer layer;
bool dofcs; /* !< FCS active */
+ int __percpu *pcpu_refcnt;
};
static int cffrml_receive(struct cflayer *layr, struct cfpkt *pkt);
@@ -31,12 +33,19 @@
static u32 cffrml_rcv_error;
static u32 cffrml_rcv_checsum_error;
struct cflayer *cffrml_create(u16 phyid, bool use_fcs)
+
{
struct cffrml *this = kmalloc(sizeof(struct cffrml), GFP_ATOMIC);
if (!this) {
pr_warn("Out of memory\n");
return NULL;
}
+ this->pcpu_refcnt = alloc_percpu(int);
+ if (this->pcpu_refcnt == NULL) {
+ kfree(this);
+ return NULL;
+ }
+
caif_assert(offsetof(struct cffrml, layer) == 0);
memset(this, 0, sizeof(struct cflayer));
@@ -49,6 +58,13 @@
return (struct cflayer *) this;
}
+void cffrml_free(struct cflayer *layer)
+{
+ struct cffrml *this = container_obj(layer);
+ free_percpu(this->pcpu_refcnt);
+ kfree(layer);
+}
+
void cffrml_set_uplayer(struct cflayer *this, struct cflayer *up)
{
this->up = up;
@@ -148,8 +164,23 @@
void cffrml_put(struct cflayer *layr)
{
+ struct cffrml *this = container_obj(layr);
+ if (layr != NULL && this->pcpu_refcnt != NULL)
+ irqsafe_cpu_dec(*this->pcpu_refcnt);
}
void cffrml_hold(struct cflayer *layr)
{
+ struct cffrml *this = container_obj(layr);
+ if (layr != NULL && this->pcpu_refcnt != NULL)
+ irqsafe_cpu_inc(*this->pcpu_refcnt);
+}
+
+int cffrml_refcnt_read(struct cflayer *layr)
+{
+ int i, refcnt = 0;
+ struct cffrml *this = container_obj(layr);
+ for_each_possible_cpu(i)
+ refcnt += *per_cpu_ptr(this->pcpu_refcnt, i);
+ return refcnt;
}
