| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-Id: <1305290648-9613-2-git-send-email-sjur.brandeland@stericsson.com>
Date: Fri, 13 May 2011 14:43:59 +0200
From: Sjur Brændeland <sjur.brandeland@...ricsson.com>
To: "David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org
Cc: Sjur Brændeland <sjur.brandeland@...ricsson.com>
Subject: [net-next-2.6 01/10] caif: Use rcu_read_lock in CAIF mux layer.
Replace spin_lock with rcu_read_lock when accessing lists to layers
and cache. While packets are in flight rcu_read_lock should not be held,
instead ref-counters are used in combination with RCU.
Signed-off-by: Sjur Brændeland <sjur.brandeland@...ricsson.com>
---
include/net/caif/cffrml.h | 2 +
net/caif/cffrml.c | 8 +++
net/caif/cfmuxl.c | 119 ++++++++++++++++++++++++++++-----------------
3 files changed, 85 insertions(+), 44 deletions(-)
diff --git a/include/net/caif/cffrml.h b/include/net/caif/cffrml.h
index 3f14d2e..4f126d7 100644
--- a/include/net/caif/cffrml.h
+++ b/include/net/caif/cffrml.h
@@ -12,5 +12,7 @@ struct cffrml;
struct cflayer *cffrml_create(u16 phyid, bool DoFCS);
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);
#endif /* CFFRML_H_ */
diff --git a/net/caif/cffrml.c b/net/caif/cffrml.c
index 2423fed..f4b8892 100644
--- a/net/caif/cffrml.c
+++ b/net/caif/cffrml.c
@@ -145,3 +145,11 @@ static void cffrml_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
if (layr->up->ctrlcmd)
layr->up->ctrlcmd(layr->up, ctrl, layr->id);
}
+
+void cffrml_put(struct cflayer *layr)
+{
+}
+
+void cffrml_hold(struct cflayer *layr)
+{
+}
diff --git a/net/caif/cfmuxl.c b/net/caif/cfmuxl.c
index fc24974..2a56df7 100644
--- a/net/caif/cfmuxl.c
+++ b/net/caif/cfmuxl.c
@@ -9,6 +9,7 @@
#include <linux/stddef.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
+#include <linux/rculist.h>
#include <net/caif/cfpkt.h>
#include <net/caif/cfmuxl.h>
#include <net/caif/cfsrvl.h>
@@ -64,31 +65,31 @@ struct cflayer *cfmuxl_create(void)
int cfmuxl_set_uplayer(struct cflayer *layr, struct cflayer *up, u8 linkid)
{
struct cfmuxl *muxl = container_obj(layr);
- spin_lock(&muxl->receive_lock);
- cfsrvl_get(up);
- list_add(&up->node, &muxl->srvl_list);
- spin_unlock(&muxl->receive_lock);
+
+ spin_lock_bh(&muxl->receive_lock);
+ list_add_rcu(&up->node, &muxl->srvl_list);
+ spin_unlock_bh(&muxl->receive_lock);
return 0;
}
int cfmuxl_set_dnlayer(struct cflayer *layr, struct cflayer *dn, u8 phyid)
{
struct cfmuxl *muxl = (struct cfmuxl *) layr;
- spin_lock(&muxl->transmit_lock);
- list_add(&dn->node, &muxl->frml_list);
- spin_unlock(&muxl->transmit_lock);
+
+ spin_lock_bh(&muxl->transmit_lock);
+ list_add_rcu(&dn->node, &muxl->frml_list);
+ spin_unlock_bh(&muxl->transmit_lock);
return 0;
}
static struct cflayer *get_from_id(struct list_head *list, u16 id)
{
- struct list_head *node;
- struct cflayer *layer;
- list_for_each(node, list) {
- layer = list_entry(node, struct cflayer, node);
- if (layer->id == id)
- return layer;
+ struct cflayer *lyr;
+ list_for_each_entry_rcu(lyr, list, node) {
+ if (lyr->id == id)
+ return lyr;
}
+
return NULL;
}
@@ -96,41 +97,45 @@ struct cflayer *cfmuxl_remove_dnlayer(struct cflayer *layr, u8 phyid)
{
struct cfmuxl *muxl = container_obj(layr);
struct cflayer *dn;
- spin_lock(&muxl->transmit_lock);
- memset(muxl->dn_cache, 0, sizeof(muxl->dn_cache));
+ int idx = phyid % DN_CACHE_SIZE;
+
+ spin_lock_bh(&muxl->transmit_lock);
+ rcu_assign_pointer(muxl->dn_cache[idx], NULL);
dn = get_from_id(&muxl->frml_list, phyid);
- if (dn == NULL) {
- spin_unlock(&muxl->transmit_lock);
- return NULL;
- }
- list_del(&dn->node);
+ if (dn == NULL)
+ goto out;
+
+ list_del_rcu(&dn->node);
caif_assert(dn != NULL);
- spin_unlock(&muxl->transmit_lock);
+out:
+ spin_unlock_bh(&muxl->transmit_lock);
return dn;
}
-/* Invariant: lock is taken */
static struct cflayer *get_up(struct cfmuxl *muxl, u16 id)
{
struct cflayer *up;
int idx = id % UP_CACHE_SIZE;
- up = muxl->up_cache[idx];
+ up = rcu_dereference(muxl->up_cache[idx]);
if (up == NULL || up->id != id) {
+ spin_lock_bh(&muxl->receive_lock);
up = get_from_id(&muxl->srvl_list, id);
- muxl->up_cache[idx] = up;
+ rcu_assign_pointer(muxl->up_cache[idx], up);
+ spin_unlock_bh(&muxl->receive_lock);
}
return up;
}
-/* Invariant: lock is taken */
static struct cflayer *get_dn(struct cfmuxl *muxl, struct dev_info *dev_info)
{
struct cflayer *dn;
int idx = dev_info->id % DN_CACHE_SIZE;
- dn = muxl->dn_cache[idx];
+ dn = rcu_dereference(muxl->dn_cache[idx]);
if (dn == NULL || dn->id != dev_info->id) {
+ spin_lock_bh(&muxl->transmit_lock);
dn = get_from_id(&muxl->frml_list, dev_info->id);
- muxl->dn_cache[idx] = dn;
+ rcu_assign_pointer(muxl->dn_cache[idx], dn);
+ spin_unlock_bh(&muxl->transmit_lock);
}
return dn;
}
@@ -139,15 +144,17 @@ struct cflayer *cfmuxl_remove_uplayer(struct cflayer *layr, u8 id)
{
struct cflayer *up;
struct cfmuxl *muxl = container_obj(layr);
- spin_lock(&muxl->receive_lock);
- up = get_up(muxl, id);
+ int idx = id % UP_CACHE_SIZE;
+
+ spin_lock_bh(&muxl->receive_lock);
+ up = get_from_id(&muxl->srvl_list, id);
if (up == NULL)
goto out;
- memset(muxl->up_cache, 0, sizeof(muxl->up_cache));
- list_del(&up->node);
- cfsrvl_put(up);
+
+ rcu_assign_pointer(muxl->up_cache[idx], NULL);
+ list_del_rcu(&up->node);
out:
- spin_unlock(&muxl->receive_lock);
+ spin_unlock_bh(&muxl->receive_lock);
return up;
}
@@ -162,22 +169,28 @@ static int cfmuxl_receive(struct cflayer *layr, struct cfpkt *pkt)
cfpkt_destroy(pkt);
return -EPROTO;
}
-
- spin_lock(&muxl->receive_lock);
+ rcu_read_lock();
up = get_up(muxl, id);
- spin_unlock(&muxl->receive_lock);
+
if (up == NULL) {
- pr_info("Received data on unknown link ID = %d (0x%x) up == NULL",
- id, id);
+ pr_debug("Received data on unknown link ID = %d (0x%x)"
+ " up == NULL", id, id);
cfpkt_destroy(pkt);
/*
* Don't return ERROR, since modem misbehaves and sends out
* flow on before linksetup response.
*/
+
+ rcu_read_unlock();
return /* CFGLU_EPROT; */ 0;
}
+
+ /* We can't hold rcu_lock during receive, so take a ref count instead */
cfsrvl_get(up);
+ rcu_read_unlock();
+
ret = up->receive(up, pkt);
+
cfsrvl_put(up);
return ret;
}
@@ -185,31 +198,49 @@ static int cfmuxl_receive(struct cflayer *layr, struct cfpkt *pkt)
static int cfmuxl_transmit(struct cflayer *layr, struct cfpkt *pkt)
{
struct cfmuxl *muxl = container_obj(layr);
+ int err;
u8 linkid;
struct cflayer *dn;
struct caif_payload_info *info = cfpkt_info(pkt);
BUG_ON(!info);
+
+ rcu_read_lock();
+
dn = get_dn(muxl, info->dev_info);
if (dn == NULL) {
- pr_warn("Send data on unknown phy ID = %d (0x%x)\n",
+ pr_debug("Send data on unknown phy ID = %d (0x%x)\n",
info->dev_info->id, info->dev_info->id);
+ rcu_read_unlock();
+ cfpkt_destroy(pkt);
return -ENOTCONN;
}
+
info->hdr_len += 1;
linkid = info->channel_id;
cfpkt_add_head(pkt, &linkid, 1);
- return dn->transmit(dn, pkt);
+
+ /* We can't hold rcu_lock during receive, so take a ref count instead */
+ cffrml_hold(dn);
+
+ rcu_read_unlock();
+
+ err = dn->transmit(dn, pkt);
+
+ cffrml_put(dn);
+ return err;
}
static void cfmuxl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
int phyid)
{
struct cfmuxl *muxl = container_obj(layr);
- struct list_head *node, *next;
struct cflayer *layer;
- list_for_each_safe(node, next, &muxl->srvl_list) {
- layer = list_entry(node, struct cflayer, node);
- if (cfsrvl_phyid_match(layer, phyid))
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(layer, &muxl->srvl_list, node) {
+ if (cfsrvl_phyid_match(layer, phyid) && layer->ctrlcmd)
+ /* NOTE: ctrlcmd is not allowed to block */
layer->ctrlcmd(layer, ctrl, phyid);
}
+ rcu_read_unlock();
}
--
1.7.1
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Powered by blists - more mailing lists