From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roel Kluin Subject: Re: [PATCH] net: variables reach -1, but 0 tested Date: Sun, 01 Feb 2009 17:23:29 +0100 Message-ID: <4985CC81.1040801@gmail.com> References: <498429AE.1080404@gmail.com> <1233434112.5903.28.camel@desktop> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, lkml To: Daniel Walker , davem@davemloft.net Return-path: Received: from ik-out-1112.google.com ([66.249.90.183]:14099 "EHLO ik-out-1112.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753899AbZBAQXd (ORCPT ); Sun, 1 Feb 2009 11:23:33 -0500 In-Reply-To: <1233434112.5903.28.camel@desktop> Sender: netdev-owner@vger.kernel.org List-ID: Daniel Walker wrote: > On Sat, 2009-01-31 at 11:36 +0100, Roel Kluin wrote: > >> >> - while (limit--) { >> + while (--limit) { >> val = phy_read(phy, MII_BMCR); >> if (val >= 0 && (val & BMCR_RESET) == 0) >> break; > > It looks like these are checked for <= to 0 , are these changes strictly > nessesary? Although the chance that this goes wrong in practice is small, my change was correct: In the last iteration, limit is 1 when the test occurs, before the decrement causes limit to become 0. If just then the break occurs, we continue after the loop with: if ((val & BMCR_ISOLATE) && limit > 0) phy_write(phy, MII_BMCR, val & ~BMCR_ISOLATE); return limit <= 0; Since limit is 0, the phy_write won't occur and the return is 1, this is not desired, I assume. With the prefix decrement limit is always greater than 0 when the break occurs. I do agree that the chance that this goes wrong in practice could be small. >> /* make sure EEPROM has finished loading before setting GPIO_CFG */ >> timeout=1000; >> - while ( timeout-- && (SMC_GET_E2P_CMD(lp) & E2P_CMD_EPC_BUSY_)) { >> + while ( --timeout && (SMC_GET_E2P_CMD(lp) & E2P_CMD_EPC_BUSY_)) { >> udelay(10); > > If your doing "timeOut" to "timeout" below may as well drop the space > above after the "(" .. Ok, here it is again: while (timeout--) { ... } timeout becomes -1 if the loop isn't ended otherwise, not 0. Signed-off-by: Roel Kluin --- drivers/net/ibm_newemac/phy.c | 4 ++-- drivers/net/smc911x.c | 4 ++-- drivers/net/smsc9420.c | 12 ++++++------ drivers/net/sungem.c | 2 +- drivers/net/sunqe.c | 2 +- drivers/net/tsi108_eth.c | 2 +- drivers/net/tulip/de2104x.c | 2 +- 7 files changed, 14 insertions(+), 14 deletions(-) diff --git a/drivers/net/ibm_newemac/phy.c b/drivers/net/ibm_newemac/phy.c index c40cd8d..ac9d964 100644 --- a/drivers/net/ibm_newemac/phy.c +++ b/drivers/net/ibm_newemac/phy.c @@ -60,7 +60,7 @@ int emac_mii_reset_phy(struct mii_phy *phy) udelay(300); - while (limit--) { + while (--limit) { val = phy_read(phy, MII_BMCR); if (val >= 0 && (val & BMCR_RESET) == 0) break; @@ -84,7 +84,7 @@ int emac_mii_reset_gpcs(struct mii_phy *phy) udelay(300); - while (limit--) { + while (--limit) { val = gpcs_phy_read(phy, MII_BMCR); if (val >= 0 && (val & BMCR_RESET) == 0) break; diff --git a/drivers/net/smc911x.c b/drivers/net/smc911x.c index bf3aa2a..223cde0 100644 --- a/drivers/net/smc911x.c +++ b/drivers/net/smc911x.c @@ -220,9 +220,9 @@ static void smc911x_reset(struct net_device *dev) /* make sure EEPROM has finished loading before setting GPIO_CFG */ timeout=1000; - while ( timeout-- && (SMC_GET_E2P_CMD(lp) & E2P_CMD_EPC_BUSY_)) { + while (--timeout && (SMC_GET_E2P_CMD(lp) & E2P_CMD_EPC_BUSY_)) udelay(10); - } + if (timeout == 0){ PRINTK("%s: smc911x_reset timeout waiting for EEPROM busy\n", dev->name); return; diff --git a/drivers/net/smsc9420.c b/drivers/net/smsc9420.c index c14a4c6..41f5303 100644 --- a/drivers/net/smsc9420.c +++ b/drivers/net/smsc9420.c @@ -498,7 +498,7 @@ static void smsc9420_check_mac_address(struct net_device *dev) static void smsc9420_stop_tx(struct smsc9420_pdata *pd) { u32 dmac_control, mac_cr, dma_intr_ena; - int timeOut = 1000; + int timeout = 1000; /* disable TX DMAC */ dmac_control = smsc9420_reg_read(pd, DMAC_CONTROL); @@ -506,13 +506,13 @@ static void smsc9420_stop_tx(struct smsc9420_pdata *pd) smsc9420_reg_write(pd, DMAC_CONTROL, dmac_control); /* Wait max 10ms for transmit process to stop */ - while (timeOut--) { + while (--timeout) { if (smsc9420_reg_read(pd, DMAC_STATUS) & DMAC_STS_TS_) break; udelay(10); } - if (!timeOut) + if (!timeout) smsc_warn(IFDOWN, "TX DMAC failed to stop"); /* ACK Tx DMAC stop bit */ @@ -596,7 +596,7 @@ static void smsc9420_free_rx_ring(struct smsc9420_pdata *pd) static void smsc9420_stop_rx(struct smsc9420_pdata *pd) { - int timeOut = 1000; + int timeout = 1000; u32 mac_cr, dmac_control, dma_intr_ena; /* mask RX DMAC interrupts */ @@ -617,13 +617,13 @@ static void smsc9420_stop_rx(struct smsc9420_pdata *pd) smsc9420_pci_flush_write(pd); /* wait up to 10ms for receive to stop */ - while (timeOut--) { + while (--timeout) { if (smsc9420_reg_read(pd, DMAC_STATUS) & DMAC_STS_RS_) break; udelay(10); } - if (!timeOut) + if (!timeout) smsc_warn(IFDOWN, "RX DMAC did not stop! timeout."); /* ACK the Rx DMAC stop bit */ diff --git a/drivers/net/sungem.c b/drivers/net/sungem.c index 86c765d..b17efa9 100644 --- a/drivers/net/sungem.c +++ b/drivers/net/sungem.c @@ -148,7 +148,7 @@ static u16 __phy_read(struct gem *gp, int phy_addr, int reg) cmd |= (MIF_FRAME_TAMSB); writel(cmd, gp->regs + MIF_FRAME); - while (limit--) { + while (--limit) { cmd = readl(gp->regs + MIF_FRAME); if (cmd & MIF_FRAME_TALSB) break; diff --git a/drivers/net/sunqe.c b/drivers/net/sunqe.c index 6e8f377..fe0c3f2 100644 --- a/drivers/net/sunqe.c +++ b/drivers/net/sunqe.c @@ -227,7 +227,7 @@ static int qe_init(struct sunqe *qep, int from_irq) if (!(sbus_readb(mregs + MREGS_PHYCONFIG) & MREGS_PHYCONFIG_LTESTDIS)) { int tries = 50; - while (tries--) { + while (--tries) { u8 tmp; mdelay(5); diff --git a/drivers/net/tsi108_eth.c b/drivers/net/tsi108_eth.c index 75461db..a9fd2b2 100644 --- a/drivers/net/tsi108_eth.c +++ b/drivers/net/tsi108_eth.c @@ -1237,7 +1237,7 @@ static void tsi108_init_phy(struct net_device *dev) spin_lock_irqsave(&phy_lock, flags); tsi108_write_mii(data, MII_BMCR, BMCR_RESET); - while (i--){ + while (--i) { if(!(tsi108_read_mii(data, MII_BMCR) & BMCR_RESET)) break; udelay(10); diff --git a/drivers/net/tulip/de2104x.c b/drivers/net/tulip/de2104x.c index d5d53b6..0bf2114 100644 --- a/drivers/net/tulip/de2104x.c +++ b/drivers/net/tulip/de2104x.c @@ -392,7 +392,7 @@ static void de_rx (struct de_private *de) unsigned drop = 0; int rc; - while (rx_work--) { + while (--rx_work) { u32 status, len; dma_addr_t mapping; struct sk_buff *skb, *copy_skb;