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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>
This commit is contained in:
sjur.brandeland@stericsson.com 2011-05-13 02:44:02 +00:00 committed by David S. Miller
parent f362144084
commit cb3cb423a0
3 changed files with 43 additions and 2 deletions
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5
include/net/caif/cffrml.h
View File

@ -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_ */

9
net/caif/cfcnfg.c
View File

@ -519,6 +519,13 @@ int cfcnfg_del_phy_layer(struct cfcnfg *cnfg, struct cflayer *phy_layer)
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 @@ int cfcnfg_del_phy_layer(struct cfcnfg *cnfg, struct cflayer *phy_layer)
if (phyinfo->phy_layer != frml_dn)
kfree(frml_dn);
kfree(frml);
cffrml_free(frml);
kfree(phyinfo);
mutex_unlock(&cnfg->lock);

31
net/caif/cffrml.c
View File

@ -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 void cffrml_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
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 @@ struct cflayer *cffrml_create(u16 phyid, bool use_fcs)
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 @@ static void cffrml_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
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;
}