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Commit e189062a authored by Faisal Latif's avatar Faisal Latif Committed by Roland Dreier
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RDMA/nes: Remove tx_free_list 



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: default avatarFaisal Latif <faisal.latif@intel.com>
Signed-off-by: default avatarChien Tung <chien.tin.tung@intel.com>
Signed-off-by: default avatarRoland Dreier <rolandd@cisco.com>
parent 6098d107

drivers/infiniband/hw/nes/nes_cm.c

+4 −72
Original line number Diff line number Diff line
@@ -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 *);
@@ -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));
@@ -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;
@@ -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;
@@ -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");
@@ -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");
@@ -771,46 +769,6 @@ 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

 */
@@ -818,13 +776,9 @@ 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;
@@ -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)
@@ -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) */
@@ -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 */
@@ -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);

drivers/infiniband/hw/nes/nes_cm.h

+2 −3
Original line number Diff line number Diff line
@@ -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;
@@ -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;
@@ -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]; */