i2o: fix notifiers when max_drivers is configured

PATCH In review Akinobu Mita 2 participants 3 messages May 20, 2007 – May 21, 2007

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Akinobu Mita

author

2007-05-20 14:34 UTC #0 lore raw

PATCH 1/1 i2o: fix notifiers when max_drivers is configured

Maxinum number of I2O drivers which could be registered is configurable by max_drivers module parameter.

But the module parameter is ignored and default value (I2O_MAX_DRIVERS = 8) is used in the loops to notify all registered drivers.

Cc Markus Lidel <[email protected]>

Signed-off-by Akinobu Mita <[email protected]>

---
 drivers/message/i2o/driver.c |   14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

drivers/message/i2o/driver.c +7 -7

Index: 2.6-mm/drivers/message/i2o/driver.c
===================================================================
@@ -20,6 +20,7 @@
 #include <linux/workqueue.h>
 #include <linux/string.h>
 #include <linux/slab.h>
+#include <linux/log2.h>
 #include "core.h"
 
 #define OSM_NAME	"i2o"

@@ -260,7 +261,7 @@ void i2o_driver_notify_controller_add_al
 	int i;
 	struct i2o_driver *drv;
 
-	for (i = 0; i < I2O_MAX_DRIVERS; i++) {
+	for (i = 0; i < i2o_max_drivers; i++) {
 		drv = i2o_drivers[i];
 
 		if (drv)

@@ -280,7 +281,7 @@ void i2o_driver_notify_controller_remove
 	int i;
 	struct i2o_driver *drv;
 
-	for (i = 0; i < I2O_MAX_DRIVERS; i++) {
+	for (i = 0; i < i2o_max_drivers; i++) {
 		drv = i2o_drivers[i];
 
 		if (drv)

@@ -299,7 +300,7 @@ void i2o_driver_notify_device_add_all(st
 	int i;
 	struct i2o_driver *drv;
 
-	for (i = 0; i < I2O_MAX_DRIVERS; i++) {
+	for (i = 0; i < i2o_max_drivers; i++) {
 		drv = i2o_drivers[i];
 
 		if (drv)

@@ -318,7 +319,7 @@ void i2o_driver_notify_device_remove_all
 	int i;
 	struct i2o_driver *drv;
 
-	for (i = 0; i < I2O_MAX_DRIVERS; i++) {
+	for (i = 0; i < i2o_max_drivers; i++) {
 		drv = i2o_drivers[i];
 
 		if (drv)

@@ -340,8 +341,7 @@ int __init i2o_driver_init(void)
 	spin_lock_init(&i2o_drivers_lock);
 
 	if ((i2o_max_drivers < 2) || (i2o_max_drivers > 64) ||
-	    ((i2o_max_drivers ^ (i2o_max_drivers - 1)) !=
-	     (2 * i2o_max_drivers - 1))) {
+	    !is_power_of_2(i2o_max_drivers)) {
 		osm_warn("max_drivers set to %d, but must be >=2 and <= 64 and "
 			 "a power of 2\n", i2o_max_drivers);
 		i2o_max_drivers = I2O_MAX_DRIVERS;

@@ -349,7 +349,7 @@ int __init i2o_driver_init(void)
 	osm_info("max drivers = %d\n", i2o_max_drivers);
 
 	i2o_drivers =
-	    kzalloc(i2o_max_drivers * sizeof(*i2o_drivers), GFP_KERNEL);
+	    kcalloc(i2o_max_drivers, sizeof(*i2o_drivers), GFP_KERNEL);
 	if (!i2o_drivers)
 		return -ENOMEM;

Andrew Morton

2007-05-21 04:19 UTC #1 lore raw

Quoted 72 lines · On Sun, 20 May 2007 23:27:28 +0900 Akinobu Mita <[email protected]> wrote:

Maxinum number of I2O drivers which could be registered is configurable by max_drivers module parameter.

But the module parameter is ignored and default value (I2O_MAX_DRIVERS = 8) is used in the loops to notify all registered drivers.

Cc Markus Lidel <[email protected]>

Signed-off-by Akinobu Mita <[email protected]>

---
 drivers/message/i2o/driver.c |   14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

Index: 2.6-mm/drivers/message/i2o/driver.c
===================================================================

drivers/message/i2o/driver.c +6 -6

@@ -20,6 +20,7 @@
 #include <linux/workqueue.h>
 #include <linux/string.h>
 #include <linux/slab.h>
+#include <linux/log2.h>
 #include "core.h"
 
 #define OSM_NAME	"i2o"

@@ -260,7 +261,7 @@ void i2o_driver_notify_controller_add_al
 	int i;
 	struct i2o_driver *drv;
 
-	for (i = 0; i < I2O_MAX_DRIVERS; i++) {
+	for (i = 0; i < i2o_max_drivers; i++) {
 		drv = i2o_drivers[i];
 
 		if (drv)

@@ -280,7 +281,7 @@ void i2o_driver_notify_controller_remove
 	int i;
 	struct i2o_driver *drv;
 
-	for (i = 0; i < I2O_MAX_DRIVERS; i++) {
+	for (i = 0; i < i2o_max_drivers; i++) {
 		drv = i2o_drivers[i];
 
 		if (drv)

@@ -299,7 +300,7 @@ void i2o_driver_notify_device_add_all(st
 	int i;
 	struct i2o_driver *drv;
 
-	for (i = 0; i < I2O_MAX_DRIVERS; i++) {
+	for (i = 0; i < i2o_max_drivers; i++) {
 		drv = i2o_drivers[i];
 
 		if (drv)

@@ -318,7 +319,7 @@ void i2o_driver_notify_device_remove_all
 	int i;
 	struct i2o_driver *drv;
 
-	for (i = 0; i < I2O_MAX_DRIVERS; i++) {
+	for (i = 0; i < i2o_max_drivers; i++) {
 		drv = i2o_drivers[i];
 
 		if (drv)

@@ -340,8 +341,7 @@ int __init i2o_driver_init(void)
 	spin_lock_init(&i2o_drivers_lock);
 
 	if ((i2o_max_drivers < 2) || (i2o_max_drivers > 64) ||
-	    ((i2o_max_drivers ^ (i2o_max_drivers - 1)) !=
-	     (2 * i2o_max_drivers - 1))) {
+	    !is_power_of_2(i2o_max_drivers)) {
 		osm_warn("max_drivers set to %d, but must be >=2 and <= 64 and "
 			 "a power of 2\n", i2o_max_drivers);
 		i2o_max_drivers = I2O_MAX_DRIVERS;

drivers/message/i2o/driver.c int __init i2o_driver_init(void) · line 355

Quoted 8 lines

drivers/message/i2o/driver.c +1 -1

@@ -349,7 +349,7 @@ int __init i2o_driver_init(void)
 	osm_info("max drivers = %d\n", i2o_max_drivers);
 
 	i2o_drivers =
-	    kzalloc(i2o_max_drivers * sizeof(*i2o_drivers), GFP_KERNEL);
+	    kcalloc(i2o_max_drivers, sizeof(*i2o_drivers), GFP_KERNEL);
 	if (!i2o_drivers)
 		return -ENOMEM;

Is there any particular reason why i2o_max_drivers must be a power of two? It seems a peculiar constraint.

Akinobu Mita

author

2007-05-21 17:05 UTC #2 lore raw

Quoted 13 lines · Andrew Morton

Review int __init i2o_driver_init(void) · line 347

Quoted 10 lines

(quoted diff) +1 -2

@@ -340,8 +341,7 @@ int __init i2o_driver_init(void)
 	spin_lock_init(&i2o_drivers_lock);
 
 	if ((i2o_max_drivers < 2) || (i2o_max_drivers > 64) ||
-	    ((i2o_max_drivers ^ (i2o_max_drivers - 1)) !=
-	     (2 * i2o_max_drivers - 1))) {
+	    !is_power_of_2(i2o_max_drivers)) {
 		osm_warn("max_drivers set to %d, but must be >=2 and <= 64 and "
 			 "a power of 2\n", i2o_max_drivers);
 		i2o_max_drivers = I2O_MAX_DRIVERS;

Is there any particular reason why i2o_max_drivers must be a power of two? It seems a peculiar constraint.

I can't find the reason.

Subject: [patch -mm] i2o: eliminate a peculiar constraint on i2o_max_drivers

There is no reason i2o_max_drivers must be a power of two. This patch eliminates such a constraint.

Cc Markus Lidel <[email protected]>

Signed-off-by Akinobu Mita <[email protected]>

---
 drivers/message/i2o/driver.c |    8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

drivers/message/i2o/driver.c +3 -5

Index: 2.6-mm/drivers/message/i2o/driver.c
===================================================================
@@ -20,7 +20,6 @@
 #include <linux/workqueue.h>
 #include <linux/string.h>
 #include <linux/slab.h>
-#include <linux/log2.h>
 #include "core.h"
 
 #define OSM_NAME	"i2o"

@@ -340,10 +339,9 @@ int __init i2o_driver_init(void)
 
 	spin_lock_init(&i2o_drivers_lock);
 
-	if ((i2o_max_drivers < 2) || (i2o_max_drivers > 64) ||
-	    !is_power_of_2(i2o_max_drivers)) {
-		osm_warn("max_drivers set to %d, but must be >=2 and <= 64 and "
-			 "a power of 2\n", i2o_max_drivers);
+	if ((i2o_max_drivers < 2) || (i2o_max_drivers > 64)) {
+		osm_warn("max_drivers set to %d, but must be >=2 and <= 64\n",
+			 i2o_max_drivers);
 		i2o_max_drivers = I2O_MAX_DRIVERS;
 	}
 	osm_info("max drivers = %d\n", i2o_max_drivers);