From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: [patch 4/9] sky2: use mask instead of modulo operation Date: Mon, 08 May 2006 15:11:29 -0700 Message-ID: <20060508221228.811857000@localhost.localdomain> References: <20060508221125.177816000@localhost.localdomain> Return-path: Received: from smtp.osdl.org ([65.172.181.4]:11965 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S1751306AbWEHWXw (ORCPT ); Mon, 8 May 2006 18:23:52 -0400 Received: from shell0.pdx.osdl.net (fw.osdl.org [65.172.181.6]) by smtp.osdl.org (8.12.8/8.12.8) with ESMTP id k48MNmtH003751 (version=TLSv1/SSLv3 cipher=EDH-RSA-DES-CBC3-SHA bits=168 verify=NO) for ; Mon, 8 May 2006 15:23:49 -0700 Received: from shell0.pdx.osdl.net (localhost [127.0.0.1]) by shell0.pdx.osdl.net (8.13.1/8.11.6) with ESMTP id k48MNmtJ023554 for ; Mon, 8 May 2006 15:23:48 -0700 To: netdev@vger.kernel.org Content-Disposition: inline; filename=sky2-ring-math.patch Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Gcc isn't smart enough to know that it can do a modulo operation with power of 2 constant by doing a mask. So add macro to do it for us. Signed-off-by: Stephen Hemminger --- sky2.orig/drivers/net/sky2.c +++ sky2/drivers/net/sky2.c @@ -79,6 +79,8 @@ #define NAPI_WEIGHT 64 #define PHY_RETRIES 1000 +#define RING_NEXT(x,s) (((x)+1) & ((s)-1)) + static const u32 default_msg = NETIF_MSG_DRV | NETIF_MSG_PROBE | NETIF_MSG_LINK | NETIF_MSG_TIMER | NETIF_MSG_TX_ERR | NETIF_MSG_RX_ERR @@ -719,7 +721,7 @@ static inline struct sky2_tx_le *get_tx_ { struct sky2_tx_le *le = sky2->tx_le + sky2->tx_prod; - sky2->tx_prod = (sky2->tx_prod + 1) % TX_RING_SIZE; + sky2->tx_prod = RING_NEXT(sky2->tx_prod, TX_RING_SIZE); return le; } @@ -735,7 +737,7 @@ static inline void sky2_put_idx(struct s static inline struct sky2_rx_le *sky2_next_rx(struct sky2_port *sky2) { struct sky2_rx_le *le = sky2->rx_le + sky2->rx_put; - sky2->rx_put = (sky2->rx_put + 1) % RX_LE_SIZE; + sky2->rx_put = RING_NEXT(sky2->rx_put, RX_LE_SIZE); return le; } @@ -1078,7 +1080,7 @@ err_out: /* Modular subtraction in ring */ static inline int tx_dist(unsigned tail, unsigned head) { - return (head - tail) % TX_RING_SIZE; + return (head - tail) & (TX_RING_SIZE - 1); } /* Number of list elements available for next tx */ @@ -1255,7 +1257,7 @@ static int sky2_xmit_frame(struct sk_buf le->opcode = OP_BUFFER | HW_OWNER; fre = sky2->tx_ring - + ((re - sky2->tx_ring) + i + 1) % TX_RING_SIZE; + + RING_NEXT((re - sky2->tx_ring) + i, TX_RING_SIZE); pci_unmap_addr_set(fre, mapaddr, mapping); } @@ -1315,7 +1317,7 @@ static void sky2_tx_complete(struct sky2 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { struct tx_ring_info *fre; - fre = sky2->tx_ring + (put + i + 1) % TX_RING_SIZE; + fre = sky2->tx_ring + RING_NEXT(put + i, TX_RING_SIZE); pci_unmap_page(pdev, pci_unmap_addr(fre, mapaddr), skb_shinfo(skb)->frags[i].size, PCI_DMA_TODEVICE); @@ -1876,7 +1878,7 @@ static int sky2_status_intr(struct sky2_ break; opcode &= ~HW_OWNER; - hw->st_idx = (hw->st_idx + 1) % STATUS_RING_SIZE; + hw->st_idx = RING_NEXT(hw->st_idx, STATUS_RING_SIZE); le->opcode = 0; link = le->link; --