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RDMA/nes: Remove tx_free_list
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There is no lock protecting tx_free_list thus causing a system crash
when skb_dequeue() is called and the list is empty.  Since it did not give
any performance boost under heavy load, remove it to simplify the code.
Replace get_free_pkt() with dev_alloc_skb() to allocate MAX_CM_BUFFER skb
for connection establishment/teardown as well as MPA request/response.

Signed-off-by: Faisal Latif <faisal.latif@intel.com>
Signed-off-by: Chien Tung <chien.tin.tung@intel.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
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Faisal Latif authored and Roland Dreier committed Dec 25, 2008
1 parent 6098d10 commit e189062
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Showing 2 changed files with 6 additions and 75 deletions.
76 changes: 4 additions & 72 deletions drivers/infiniband/hw/nes/nes_cm.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -94,7 +94,6 @@ static int mini_cm_set(struct nes_cm_core *, u32, u32);

static void form_cm_frame(struct sk_buff *, struct nes_cm_node *,
void *, u32, void *, u32, u8);
static struct sk_buff *get_free_pkt(struct nes_cm_node *cm_node);
static int add_ref_cm_node(struct nes_cm_node *);
static int rem_ref_cm_node(struct nes_cm_core *, struct nes_cm_node *);

Expand Down Expand Up @@ -355,7 +354,6 @@ static void print_core(struct nes_cm_core *core)

nes_debug(NES_DBG_CM, "State : %u \n", core->state);

nes_debug(NES_DBG_CM, "Tx Free cnt : %u \n", skb_queue_len(&core->tx_free_list));
nes_debug(NES_DBG_CM, "Listen Nodes : %u \n", atomic_read(&core->listen_node_cnt));
nes_debug(NES_DBG_CM, "Active Nodes : %u \n", atomic_read(&core->node_cnt));

Expand Down Expand Up @@ -688,7 +686,7 @@ static int send_syn(struct nes_cm_node *cm_node, u32 sendack,
optionssize += 1;

if (!skb)
skb = get_free_pkt(cm_node);
skb = dev_alloc_skb(MAX_CM_BUFFER);
if (!skb) {
nes_debug(NES_DBG_CM, "Failed to get a Free pkt\n");
return -1;
Expand All @@ -713,7 +711,7 @@ static int send_reset(struct nes_cm_node *cm_node, struct sk_buff *skb)
int flags = SET_RST | SET_ACK;

if (!skb)
skb = get_free_pkt(cm_node);
skb = dev_alloc_skb(MAX_CM_BUFFER);
if (!skb) {
nes_debug(NES_DBG_CM, "Failed to get a Free pkt\n");
return -1;
Expand All @@ -734,7 +732,7 @@ static int send_ack(struct nes_cm_node *cm_node, struct sk_buff *skb)
int ret;

if (!skb)
skb = get_free_pkt(cm_node);
skb = dev_alloc_skb(MAX_CM_BUFFER);

if (!skb) {
nes_debug(NES_DBG_CM, "Failed to get a Free pkt\n");
Expand All @@ -757,7 +755,7 @@ static int send_fin(struct nes_cm_node *cm_node, struct sk_buff *skb)

/* if we didn't get a frame get one */
if (!skb)
skb = get_free_pkt(cm_node);
skb = dev_alloc_skb(MAX_CM_BUFFER);

if (!skb) {
nes_debug(NES_DBG_CM, "Failed to get a Free pkt\n");
Expand All @@ -771,60 +769,16 @@ static int send_fin(struct nes_cm_node *cm_node, struct sk_buff *skb)
}


/**
* get_free_pkt
*/
static struct sk_buff *get_free_pkt(struct nes_cm_node *cm_node)
{
struct sk_buff *skb, *new_skb;

/* check to see if we need to repopulate the free tx pkt queue */
if (skb_queue_len(&cm_node->cm_core->tx_free_list) < NES_CM_FREE_PKT_LO_WATERMARK) {
while (skb_queue_len(&cm_node->cm_core->tx_free_list) <
cm_node->cm_core->free_tx_pkt_max) {
/* replace the frame we took, we won't get it back */
new_skb = dev_alloc_skb(cm_node->cm_core->mtu);
BUG_ON(!new_skb);
/* add a replacement frame to the free tx list head */
skb_queue_head(&cm_node->cm_core->tx_free_list, new_skb);
}
}

skb = skb_dequeue(&cm_node->cm_core->tx_free_list);

return skb;
}


/**
* make_hashkey - generate hash key from node tuple
*/
static inline int make_hashkey(u16 loc_port, nes_addr_t loc_addr, u16 rem_port,
nes_addr_t rem_addr)
{
u32 hashkey = 0;

hashkey = loc_addr + rem_addr + loc_port + rem_port;
hashkey = (hashkey % NES_CM_HASHTABLE_SIZE);

return hashkey;
}


/**
* find_node - find a cm node that matches the reference cm node
*/
static struct nes_cm_node *find_node(struct nes_cm_core *cm_core,
u16 rem_port, nes_addr_t rem_addr, u16 loc_port, nes_addr_t loc_addr)
{
unsigned long flags;
u32 hashkey;
struct list_head *hte;
struct nes_cm_node *cm_node;

/* make a hash index key for this packet */
hashkey = make_hashkey(loc_port, loc_addr, rem_port, rem_addr);

/* get a handle on the hte */
hte = &cm_core->connected_nodes;

Expand Down Expand Up @@ -892,7 +846,6 @@ static struct nes_cm_listener *find_listener(struct nes_cm_core *cm_core,
static int add_hte_node(struct nes_cm_core *cm_core, struct nes_cm_node *cm_node)
{
unsigned long flags;
u32 hashkey;
struct list_head *hte;

if (!cm_node || !cm_core)
Expand All @@ -901,11 +854,6 @@ static int add_hte_node(struct nes_cm_core *cm_core, struct nes_cm_node *cm_node
nes_debug(NES_DBG_CM, "Adding Node %p to Active Connection HT\n",
cm_node);

/* first, make an index into our hash table */
hashkey = make_hashkey(cm_node->loc_port, cm_node->loc_addr,
cm_node->rem_port, cm_node->rem_addr);
cm_node->hashkey = hashkey;

spin_lock_irqsave(&cm_core->ht_lock, flags);

/* get a handle on the hash table element (list head for this slot) */
Expand Down Expand Up @@ -2198,10 +2146,7 @@ static int mini_cm_recv_pkt(struct nes_cm_core *cm_core,
*/
static struct nes_cm_core *nes_cm_alloc_core(void)
{
int i;

struct nes_cm_core *cm_core;
struct sk_buff *skb = NULL;

/* setup the CM core */
/* alloc top level core control structure */
Expand All @@ -2219,19 +2164,6 @@ static struct nes_cm_core *nes_cm_alloc_core(void)

atomic_set(&cm_core->events_posted, 0);

/* init the packet lists */
skb_queue_head_init(&cm_core->tx_free_list);

for (i = 0; i < NES_CM_DEFAULT_FRAME_CNT; i++) {
skb = dev_alloc_skb(cm_core->mtu);
if (!skb) {
kfree(cm_core);
return NULL;
}
/* add 'raw' skb to free frame list */
skb_queue_head(&cm_core->tx_free_list, skb);
}

cm_core->api = &nes_cm_api;

spin_lock_init(&cm_core->ht_lock);
Expand Down
5 changes: 2 additions & 3 deletions drivers/infiniband/hw/nes/nes_cm.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -165,6 +165,8 @@ struct nes_timer_entry {

#define NES_CM_DEF_SEQ2 0x18ed5740
#define NES_CM_DEF_LOCAL_ID2 0xb807
#define MAX_CM_BUFFER 512


typedef u32 nes_addr_t;

Expand Down Expand Up @@ -258,8 +260,6 @@ struct nes_cm_listener {

/* per connection node and node state information */
struct nes_cm_node {
u32 hashkey;

nes_addr_t loc_addr, rem_addr;
u16 loc_port, rem_port;

Expand Down Expand Up @@ -357,7 +357,6 @@ struct nes_cm_core {
u32 mtu;
u32 free_tx_pkt_max;
u32 rx_pkt_posted;
struct sk_buff_head tx_free_list;
atomic_t ht_node_cnt;
struct list_head connected_nodes;
/* struct list_head hashtable[NES_CM_HASHTABLE_SIZE]; */
Expand Down

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