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Commit cb3cb423 authored by sjur.brandeland@stericsson.com's avatar sjur.brandeland@stericsson.com Committed by David S. Miller
Browse files

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: default avatarSjur Brændeland <sjur.brandeland@stericsson.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f3621440

include/net/caif/cffrml.h

+4 −1
Original line number Diff line number Diff line
@@ -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_ */

net/caif/cfcnfg.c

+8 −1
Original line number Diff line number Diff line
@@ -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);

net/caif/cffrml.c

+31 −0
Original line number Diff line number Diff line
@@ -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;

}