e100 net driver update 4/4:

- switch to yield function as suggested by you, Arjan and Andrew.
- fixed broken logic in the use of time_before/time_after - possible
bug cause in previous design - in most of the places we were going to sleep
and than check if time expires before checking if condition is satisfied.
If, for example, we needed to wait up to 3 jiffies we could do
schedule_timeout(1) and get up after 4 ticks check that time expired and go
away crying about failure without checking that condition is OK.(in fact I
saw it happen on one SMP platform here).

drivers/net/e100/e100.h

@@ -138,10 +138,6 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #define TX_THRSHLD     8
 
-/* sleep time is at least 50 ms, in jiffies */
-#define SLEEP_TIME ((HZ / 20) + 1)
-#define CUS_TIMEOUT 1000
-
 /* IFS parameters */
 #define MIN_NUMBER_OF_TRANSMITS_100 1000
 #define MIN_NUMBER_OF_TRANSMITS_10  100
@@ -1019,6 +1015,14 @@ extern unsigned char e100_selftest(struct e100_private *bdp, u32 *st_timeout,
 extern unsigned char e100_get_link_state(struct e100_private *bdp);
 extern unsigned char e100_wait_scb(struct e100_private *bdp);
 
+#ifndef yield
+#define yield()					\
+        do {					\
+                current->policy |= SCHED_YIELD;	\
+                schedule();			\
+        } while (0)                                     
+#endif
+
 extern void e100_deisolate_driver(struct e100_private *bdp,
 				  u8 recover, u8 full_reset);
 extern unsigned char e100_hw_reset_recover(struct e100_private *bdp,

drivers/net/e100/e100_eeprom.c

@@ -137,7 +137,7 @@ eeprom_set_semaphore(struct e100_private *adapter)
 	u16 data = 0;
 	unsigned long expiration_time = jiffies + HZ / 100 + 1;
 
-	while (time_before(jiffies, expiration_time)) {
+	do {
 		// Get current value of General Control 2
 		data = readb(&CSR_GENERAL_CONTROL2_FIELD(adapter));
 
@@ -154,10 +154,12 @@ eeprom_set_semaphore(struct e100_private *adapter)
 			return true;
 		}
 
-		set_current_state(TASK_UNINTERRUPTIBLE);
-		schedule_timeout(1+(HZ-1)/100);
-	}
-	return false;
+		if (time_before(jiffies, expiration_time))
+			yield();
+		else
+			return false;
+
+	} while (true);
 }
 
 //----------------------------------------------------------------------------------------
@@ -579,17 +581,16 @@ eeprom_wait_cmd_done(struct e100_private *adapter)
 
 	eeprom_stand_by(adapter);
 
-	while (time_before(jiffies, expiration_time)) {
+	do {
 		rmb();
 		x = readw(&CSR_EEPROM_CONTROL_FIELD(adapter));
 		if (x & EEDO)
 			return true;
-
-		set_current_state(TASK_UNINTERRUPTIBLE);
-		schedule_timeout(1+(HZ-1)/100);
-	}
-
-	return false;
+		if (time_before(jiffies, expiration_time))
+			yield();
+		else
+			return false;
+	} while (true);
 }
 
 //----------------------------------------------------------------------------------------

drivers/net/e100/e100_main.c

@@ -165,7 +165,7 @@ static void e100_non_tx_background(unsigned long);
 /* Global Data structures and variables */
 char e100_copyright[] __devinitdata = "Copyright (c) 2002 Intel Corporation";
 
-#define E100_VERSION  "2.0.23-pre2"
+#define E100_VERSION  "2.0.24-pre1"
 
 #define E100_FULL_DRIVER_NAME 	"Intel(R) PRO/100 Fast Ethernet Adapter - Loadable driver, ver "
 
@@ -2705,7 +2705,7 @@ e100_exec_non_cu_cmd(struct e100_private *bdp, nxmit_cb_entry_t *command)
 	cb_header_t *ntcb_hdr;
 	unsigned long lock_flag;
 	unsigned long expiration_time;
-	unsigned char rc = false;
+	unsigned char rc = true;
 
 	ntcb_hdr = (cb_header_t *) command->non_tx_cmd;	/* get hdr of non tcb cmd */
 
@@ -2740,6 +2740,7 @@ e100_exec_non_cu_cmd(struct e100_private *bdp, nxmit_cb_entry_t *command)
 
 	if (!e100_wait_exec_cmplx(bdp, command->dma_addr, SCB_CUC_START)) {
 		spin_unlock_irqrestore(&(bdp->bd_lock), lock_flag);
+		rc = false;
 		goto exit;
 	}
 
@@ -2748,20 +2749,21 @@ e100_exec_non_cu_cmd(struct e100_private *bdp, nxmit_cb_entry_t *command)
 
 	/* now wait for completion of non-cu CB up to 20 msec */
 	expiration_time = jiffies + HZ / 50 + 1;
-	while (time_before(jiffies, expiration_time)) {
-		rmb();
-		if ((ntcb_hdr->cb_status &
+	rmb();
+	while (!(ntcb_hdr->cb_status &
 		     __constant_cpu_to_le16(CB_STATUS_COMPLETE))) {
-			rc = true;
+
+		if (time_before(jiffies, expiration_time)) {
+			spin_unlock_bh(&(bdp->bd_non_tx_lock));
+			yield();
+			spin_lock_bh(&(bdp->bd_non_tx_lock));
+		} else {
+			rc = false;
 			goto exit;
 		}
-		spin_unlock_bh(&(bdp->bd_non_tx_lock));
-		set_current_state(TASK_UNINTERRUPTIBLE);
-		schedule_timeout(1);
-		spin_lock_bh(&(bdp->bd_non_tx_lock));
+		rmb();
 	}
 
-	/* didn't get a C bit assume command failed */
 exit:
 	e100_free_non_tx_cmd(bdp, command);
 

drivers/net/e100/e100_phy.c

@@ -653,7 +653,7 @@ static void
 e100_force_speed_duplex(struct e100_private *bdp)
 {
 	u16 control;
-	int neg_timeout = 2 * HZ;	//2 sec in jiffies
+	unsigned long expires;
 
 	bdp->flags |= DF_SPEED_FORCED;
 
@@ -696,20 +696,18 @@ e100_force_speed_duplex(struct e100_private *bdp)
 	e100_mdi_write(bdp, MII_BMCR, bdp->phy_addr, control);
 
 	/* loop must run at least once */
+	expires = jiffies + 2 * HZ;
 	do {
-		spin_unlock_bh(&(bdp->mdi_access_lock));
-
-		set_current_state(TASK_UNINTERRUPTIBLE);
-		schedule_timeout(SLEEP_TIME);
-
-		spin_lock_bh(&(bdp->mdi_access_lock));
-
-		if (e100_update_link_state(bdp)) {
+		if (e100_update_link_state(bdp) || 
+		    time_after(jiffies, expires)) {
 			break;
+		} else {
+			spin_unlock_bh(&(bdp->mdi_access_lock));
+			yield();
+			spin_lock_bh(&(bdp->mdi_access_lock));
 		}
-		neg_timeout -= SLEEP_TIME;
 
-	} while (neg_timeout > 0);
+	} while (true);
 
 	spin_unlock_bh(&(bdp->mdi_access_lock));
 }
@@ -819,7 +817,7 @@ static void
 e100_auto_neg(struct e100_private *bdp, unsigned char force_restart)
 {
 	u16 stat_reg;
-	unsigned int i;
+	unsigned long expires;
 
 	bdp->flags &= ~DF_SPEED_FORCED;
 
@@ -840,22 +838,21 @@ e100_auto_neg(struct e100_private *bdp, unsigned char force_restart)
 			       BMCR_ANENABLE | BMCR_ANRESTART);
 
 		/* wait for autoneg to complete (up to 3 seconds) */
-		for (i = 0; i < 60; i++) {
+		expires = jiffies + HZ * 3;
+		do {
 			/* now re-read the value. Sticky so read twice */
 			e100_mdi_read(bdp, MII_BMSR, bdp->phy_addr, &stat_reg);
 			e100_mdi_read(bdp, MII_BMSR, bdp->phy_addr, &stat_reg);
 
-			if (stat_reg & BMSR_ANEGCOMPLETE)
+			if ((stat_reg & BMSR_ANEGCOMPLETE) ||
+			    time_after(jiffies, expires) ) {
 				goto exit;
-
-			spin_unlock_bh(&(bdp->mdi_access_lock));
-
-			set_current_state(TASK_UNINTERRUPTIBLE);
-			schedule_timeout(SLEEP_TIME);
-
-			spin_lock_bh(&(bdp->mdi_access_lock));
-
-		}
+			} else {
+				spin_unlock_bh(&(bdp->mdi_access_lock));
+				yield();
+				spin_lock_bh(&(bdp->mdi_access_lock));
+			}
+		} while (true);
 	}
 
 exit:

drivers/net/e100/e100_proc.c

@@ -97,7 +97,8 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #ifdef E100_CONFIG_PROC_FS
 #include "e100.h"
-
+/* MDI sleep time is at least 50 ms, in jiffies */
+#define MDI_SLEEP_TIME ((HZ / 20) + 1)
 /***************************************************************************/
 /*       /proc File System Interaface Support Functions                    */
 /***************************************************************************/
@@ -230,7 +231,7 @@ set_led(struct e100_private *bdp, u16 led_mdi_op)
 	spin_unlock_bh(&bdp->mdi_access_lock);
 
 	set_current_state(TASK_UNINTERRUPTIBLE);
-	schedule_timeout(SLEEP_TIME);
+	schedule_timeout(MDI_SLEEP_TIME);
 
 	spin_lock_bh(&bdp->mdi_access_lock);