[PATCH] S2io: new txd allocation

The attached patch contains a modified scheme for allocating Tx descriptor
blocks.
More description follows.

In the old scheme, the entire Tx descriptor space was allocated in
one go. This could cause driver load to fail on systems with low(or
scattered) memory. The Tx descriptor blocks are now allocated on
per-page basis. A new structure (list_info) has been introduced in
nic_t structure to keep track of the physical and virtual addresses
of every TxD allocated this way.
Signed-off-by: Raghavendra Koushik <raghavendra.koushik@s2io.com>
Signed-off-by: Ravinandan Arakali <ravinandan.arakali@s2io.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>

drivers/net/s2io.c

@@ -305,6 +305,9 @@ static struct pci_driver s2io_driver = {
       remove:__devexit_p(s2io_rem_nic),
 };
 
+/* A simplifier macro used both by init and free shared_mem Fns(). */
+#define TXD_MEM_PAGE_CNT(len, per_each) ((len+per_each - 1) / per_each)
+
 /**
  * init_shared_mem - Allocation and Initialization of Memory
  * @nic: Device private variable.
@@ -320,6 +323,7 @@ static int init_shared_mem(struct s2io_nic *nic)
 	dma_addr_t tmp_p_addr, tmp_p_addr_next;
 	RxD_block_t *pre_rxd_blk = NULL;
 	int i, j, blk_cnt;
+	int lst_size, lst_per_page;
 	struct net_device *dev = nic->dev;
 
 	mac_info_t *mac_control;
@@ -341,39 +345,55 @@ static int init_shared_mem(struct s2io_nic *nic)
 		DBG_PRINT(ERR_DBG, "that can be used\n");
 		return FAILURE;
 	}
-	size *= (sizeof(TxD_t) * config->max_txds);
 
-	mac_control->txd_list_mem = pci_alloc_consistent
-	    (nic->pdev, size, &mac_control->txd_list_mem_phy);
-	if (!mac_control->txd_list_mem) {
+	lst_size = (sizeof(TxD_t) * config->max_txds);
+	lst_per_page = PAGE_SIZE / lst_size;
+
+	for (i = 0; i < config->tx_fifo_num; i++) {
+		int fifo_len = config->tx_cfg[i].fifo_len;
+		int list_holder_size = fifo_len * sizeof(list_info_hold_t);
+		nic->list_info[i] = kmalloc(list_holder_size, GFP_KERNEL);
+		if (!nic->list_info[i]) {
+			DBG_PRINT(ERR_DBG,
+				  "Malloc failed for list_info\n");
 			return -ENOMEM;
 		}
-	mac_control->txd_list_mem_sz = size;
-
-	tmp_v_addr = mac_control->txd_list_mem;
-	tmp_p_addr = mac_control->txd_list_mem_phy;
-	memset(tmp_v_addr, 0, size);
-
-	DBG_PRINT(INIT_DBG, "%s:List Mem PHY: 0x%llx\n", dev->name,
-		  (unsigned long long) tmp_p_addr);
-
+		memset(nic->list_info[i], 0, list_holder_size);
+	}
 	for (i = 0; i < config->tx_fifo_num; i++) {
-		mac_control->txdl_start_phy[i] = tmp_p_addr;
-		mac_control->txdl_start[i] = (TxD_t *) tmp_v_addr;
+		int page_num = TXD_MEM_PAGE_CNT(config->tx_cfg[i].fifo_len,
+						lst_per_page);
 		mac_control->tx_curr_put_info[i].offset = 0;
 		mac_control->tx_curr_put_info[i].fifo_len =
 		    config->tx_cfg[i].fifo_len - 1;
 		mac_control->tx_curr_get_info[i].offset = 0;
 		mac_control->tx_curr_get_info[i].fifo_len =
 		    config->tx_cfg[i].fifo_len - 1;
-
-		tmp_p_addr +=
-		    (config->tx_cfg[i].fifo_len * (sizeof(TxD_t)) *
-		     config->max_txds);
-		tmp_v_addr +=
-		    (config->tx_cfg[i].fifo_len * (sizeof(TxD_t)) *
-		     config->max_txds);
+		for (j = 0; j < page_num; j++) {
+			int k = 0;
+			dma_addr_t tmp_p;
+			void *tmp_v;
+			tmp_v = pci_alloc_consistent(nic->pdev,
+						     PAGE_SIZE, &tmp_p);
+			if (!tmp_v) {
+				DBG_PRINT(ERR_DBG,
+					  "pci_alloc_consistent ");
+				DBG_PRINT(ERR_DBG, "failed for TxDL\n");
+				return -ENOMEM;
+			}
+			while (k < lst_per_page) {
+				int l = (j * lst_per_page) + k;
+				if (l == config->tx_cfg[i].fifo_len)
+					goto end_txd_alloc;
+				nic->list_info[i][l].list_virt_addr =
+				    tmp_v + (k * lst_size);
+				nic->list_info[i][l].list_phy_addr =
+				    tmp_p + (k * lst_size);
+				k++;
 			}
+		}
+	}
+      end_txd_alloc:
 
 	/* Allocation and initialization of RXDs in Rings */
 	size = 0;
@@ -484,6 +504,7 @@ static void free_shared_mem(struct s2io_nic *nic)
 	dma_addr_t tmp_p_addr;
 	mac_info_t *mac_control;
 	struct config_param *config;
+	int lst_size, lst_per_page;
 
 
 	if (!nic)
@@ -492,11 +513,23 @@ static void free_shared_mem(struct s2io_nic *nic)
 	mac_control = &nic->mac_control;
 	config = &nic->config;
 
-	if (mac_control->txd_list_mem) {
-		pci_free_consistent(nic->pdev,
-				    mac_control->txd_list_mem_sz,
-				    mac_control->txd_list_mem,
-				    mac_control->txd_list_mem_phy);
+	lst_size = (sizeof(TxD_t) * config->max_txds);
+	lst_per_page = PAGE_SIZE / lst_size;
+
+	for (i = 0; i < config->tx_fifo_num; i++) {
+		int page_num = TXD_MEM_PAGE_CNT(config->tx_cfg[i].fifo_len,
+						lst_per_page);
+		for (j = 0; j < page_num; j++) {
+			int mem_blks = (j * lst_per_page);
+			if (!nic->list_info[i][mem_blks].list_virt_addr)
+				break;
+			pci_free_consistent(nic->pdev, PAGE_SIZE,
+					    nic->list_info[i][mem_blks].
+					    list_virt_addr,
+					    nic->list_info[i][mem_blks].
+					    list_phy_addr);
+		}
+		kfree(nic->list_info[i]);
 	}
 
 	size = (MAX_RXDS_PER_BLOCK + 1) * (sizeof(RxD_t));
@@ -1444,8 +1477,8 @@ void free_tx_buffers(struct s2io_nic *nic)
 
 	for (i = 0; i < config->tx_fifo_num; i++) {
 		for (j = 0; j < config->tx_cfg[i].fifo_len - 1; j++) {
-			txdp = mac_control->txdl_start[i] +
-			    (config->max_txds * j);
+			txdp = (TxD_t *) nic->list_info[i][j].
+			    list_virt_addr;
 			skb =
 			    (struct sk_buff *) ((unsigned long) txdp->
 						Host_Control);
@@ -1460,6 +1493,8 @@ void free_tx_buffers(struct s2io_nic *nic)
 		DBG_PRINT(INTR_DBG,
 			  "%s:forcibly freeing %d skbs on FIFO%d\n",
 			  dev->name, cnt, i);
+		mac_control->tx_curr_get_info[i].offset = 0;
+		mac_control->tx_curr_put_info[i].offset = 0;
 	}
 }
 
@@ -1896,7 +1931,7 @@ static void tx_intr_handler(struct s2io_nic *nic)
 {
 	XENA_dev_config_t *bar0 = (XENA_dev_config_t *) nic->bar0;
 	struct net_device *dev = (struct net_device *) nic->dev;
-	tx_curr_get_info_t offset_info, offset_info1;
+	tx_curr_get_info_t get_info, put_info;
 	struct sk_buff *skb;
 	TxD_t *txdlp;
 	register u64 val64 = 0;
@@ -1916,12 +1951,12 @@ static void tx_intr_handler(struct s2io_nic *nic)
 	writeq(val64, &bar0->tx_traffic_int);
 
 	for (i = 0; i < config->tx_fifo_num; i++) {
-		offset_info = mac_control->tx_curr_get_info[i];
-		offset_info1 = mac_control->tx_curr_put_info[i];
-		txdlp = mac_control->txdl_start[i] +
-		    (config->max_txds * offset_info.offset);
+		get_info = mac_control->tx_curr_get_info[i];
+		put_info = mac_control->tx_curr_put_info[i];
+		txdlp = (TxD_t *) nic->list_info[i][get_info.offset].
+		    list_virt_addr;
 		while ((!(txdlp->Control_1 & TXD_LIST_OWN_XENA)) &&
-		       (offset_info.offset != offset_info1.offset) &&
+		       (get_info.offset != put_info.offset) &&
 		       (txdlp->Host_Control)) {
 			/* Check for TxD errors */
 			if (txdlp->Control_1 & TXD_T_CODE) {
@@ -1971,12 +2006,12 @@ static void tx_intr_handler(struct s2io_nic *nic)
 			nic->stats.tx_bytes += skb->len;
 			dev_kfree_skb_irq(skb);
 
-			offset_info.offset++;
-			offset_info.offset %= offset_info.fifo_len + 1;
-			txdlp = mac_control->txdl_start[i] +
-			    (config->max_txds * offset_info.offset);
+			get_info.offset++;
+			get_info.offset %= get_info.fifo_len + 1;
+			txdlp = (TxD_t *) nic->list_info[i]
+			    [get_info.offset].list_virt_addr;
 			mac_control->tx_curr_get_info[i].offset =
-			    offset_info.offset;
+			    get_info.offset;
 		}
 	}
 
@@ -2327,7 +2362,9 @@ int s2io_close(struct net_device *dev)
 	XENA_dev_config_t *bar0 = (XENA_dev_config_t *) sp->bar0;
 	register u64 val64 = 0;
 	u16 cnt = 0;
+	unsigned long flags;
 
+	spin_lock_irqsave(&sp->tx_lock, flags);
 	netif_stop_queue(dev);
 
 	/* disable Tx and Rx traffic on the NIC */
@@ -2381,6 +2418,7 @@ int s2io_close(struct net_device *dev)
 	free_rx_buffers(sp);
 
 	sp->device_close_flag = TRUE;	/* Device is shut down. */
+	spin_unlock_irqrestore(&sp->tx_lock, flags);
 
 	return 0;
 }
@@ -2401,7 +2439,7 @@ int s2io_close(struct net_device *dev)
 int s2io_xmit(struct sk_buff *skb, struct net_device *dev)
 {
 	nic_t *sp = dev->priv;
-	u16 off, txd_len, frg_cnt, frg_len, i, queue, off1, queue_len;
+	u16 frg_cnt, frg_len, i, queue, queue_len, put_off, get_off;
 	register u64 val64;
 	TxD_t *txdp;
 	TxFIFO_element_t *tx_fifo;
@@ -2419,6 +2457,14 @@ int s2io_xmit(struct sk_buff *skb, struct net_device *dev)
 	DBG_PRINT(TX_DBG, "%s: In S2IO Tx routine\n", dev->name);
 
 	spin_lock_irqsave(&sp->tx_lock, flags);
+	if ((netif_queue_stopped(dev)) || (!netif_carrier_ok(dev))) {
+		DBG_PRINT(TX_DBG, "%s:s2io_xmit: Tx Queue stopped\n",
+			  dev->name);
+		dev_kfree_skb(skb);
+		spin_unlock_irqrestore(&sp->tx_lock, flags);
+		return 0;
+	}
+
 	queue = 0;
 	/* Multi FIFO Tx is disabled for now. */
 	if (!queue && tx_prio) {
@@ -2427,14 +2473,13 @@ int s2io_xmit(struct sk_buff *skb, struct net_device *dev)
 	}
 
 
-	off = (u16) mac_control->tx_curr_put_info[queue].offset;
-	off1 = (u16) mac_control->tx_curr_get_info[queue].offset;
-	txd_len = config->max_txds;
-	txdp = mac_control->txdl_start[queue] + (config->max_txds * off);
+	put_off = (u16) mac_control->tx_curr_put_info[queue].offset;
+	get_off = (u16) mac_control->tx_curr_get_info[queue].offset;
+	txdp = (TxD_t *) sp->list_info[queue][put_off].list_virt_addr;
 
 	queue_len = mac_control->tx_curr_put_info[queue].fifo_len + 1;
 	/* Avoid "put" pointer going beyond "get" pointer */
-	if (txdp->Host_Control || (((off + 1) % queue_len) == off1)) {
+	if (txdp->Host_Control || (((put_off + 1) % queue_len) == get_off)) {
 		DBG_PRINT(ERR_DBG, "Error in xmit, No free TXDs.\n");
 		netif_stop_queue(dev);
 		dev_kfree_skb(skb);
@@ -2479,8 +2524,7 @@ int s2io_xmit(struct sk_buff *skb, struct net_device *dev)
 	txdp->Control_1 |= TXD_GATHER_CODE_LAST;
 
 	tx_fifo = mac_control->tx_FIFO_start[queue];
-	val64 = (mac_control->txdl_start_phy[queue] +
-		 (sizeof(TxD_t) * txd_len * off));
+	val64 = sp->list_info[queue][put_off].list_phy_addr;
 	writeq(val64, &tx_fifo->TxDL_Pointer);
 
 	val64 = (TX_FIFO_LAST_TXD_NUM(frg_cnt) | TX_FIFO_FIRST_LIST |
@@ -2494,15 +2538,15 @@ int s2io_xmit(struct sk_buff *skb, struct net_device *dev)
 	/* Perform a PCI read to flush previous writes */
 	val64 = readq(&bar0->general_int_status);
 
-	off++;
-	off %= mac_control->tx_curr_put_info[queue].fifo_len + 1;
-	mac_control->tx_curr_put_info[queue].offset = off;
+	put_off++;
+	put_off %= mac_control->tx_curr_put_info[queue].fifo_len + 1;
+	mac_control->tx_curr_put_info[queue].offset = put_off;
 
 	/* Avoid "put" pointer going beyond "get" pointer */
-	if (((off + 1) % queue_len) == off1) {
+	if (((put_off + 1) % queue_len) == get_off) {
 		DBG_PRINT(TX_DBG,
 			  "No free TxDs for xmit, Put: 0x%x Get:0x%x\n",
-			  off, off1);
+			  put_off, get_off);
 		netif_stop_queue(dev);
 	}
 
@@ -3070,7 +3114,7 @@ static void s2io_ethtool_getpause_data(struct net_device *dev,
 }
 
 /**
- * s2io_ethtool-setpause_data -  set/reset pause frame generation.
+ * s2io_ethtool_setpause_data -  set/reset pause frame generation.
  * @sp : private member of the device structure, which is a pointer to the 
  *      s2io_nic structure.
  * @ep : pointer to the structure with pause parameters given by ethtool.

drivers/net/s2io.h

@@ -444,6 +444,12 @@ typedef struct _TxD {
 	u64 Host_Control;	/* reserved for host */
 } TxD_t;
 
+/* Structure to hold the phy and virt addr of every TxDL. */
+typedef struct list_info_hold {
+	dma_addr_t list_phy_addr;
+	void *list_virt_addr;
+} list_info_hold_t;
+
 /* Rx descriptor structure */
 typedef struct _RxD_t {
 	u64 Host_Control;	/* reserved for host */
@@ -532,17 +538,9 @@ typedef struct mac_info {
 	u16 mc_pause_threshold_q4q7;
 
 /* tx side stuff */
-	void *txd_list_mem;	/* original pointer to allocated mem */
-	dma_addr_t txd_list_mem_phy;
-	u32 txd_list_mem_sz;
-
 	/* logical pointer of start of each Tx FIFO */
 	TxFIFO_element_t *tx_FIFO_start[MAX_TX_FIFOS];
 
-	/* The Phy and virtual mem loactions of the Tx descriptors. */
-	TxD_t *txdl_start[MAX_TX_FIFOS];
-	dma_addr_t txdl_start_phy[MAX_TX_FIFOS];
-
 /* Current offset within tx_FIFO_start, where driver would write new Tx frame*/
 	tx_curr_put_info_t tx_curr_put_info[MAX_TX_FIFOS];
 	tx_curr_get_info_t tx_curr_get_info[MAX_TX_FIFOS];
@@ -638,6 +636,9 @@ typedef struct s2io_nic {
 	int block_count[MAX_RX_RINGS];
 	int pkt_cnt[MAX_RX_RINGS];
 
+	/* Place holder of all the TX List's Phy and Virt addresses. */
+	list_info_hold_t *list_info[MAX_TX_FIFOS];
+
 	/*  Id timer, used to blink NIC to physically identify NIC. */
 	struct timer_list id_timer;