X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=block%2Fblk-sysfs.c;h=304ec73ab8215f270cbea1a50e870fd8b5b7bf54;hb=8e1bf9ffb1aca693e3cf4a4f7144c8f70c8a08b0;hp=bc28776ba76ab710efe936e93893272f9cb89d8b;hpb=bd45ac0c5daae35e7c71138172e63df5cf644cf6;p=linux-2.6

diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index bc28776ba7..304ec73ab8 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -135,6 +135,27 @@ static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
 	return queue_var_show(max_hw_sectors_kb, (page));
 }
 
+static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
+{
+	return queue_var_show(blk_queue_nomerges(q), page);
+}
+
+static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
+				    size_t count)
+{
+	unsigned long nm;
+	ssize_t ret = queue_var_store(&nm, page, count);
+
+	spin_lock_irq(q->queue_lock);
+	if (nm)
+		queue_flag_set(QUEUE_FLAG_NOMERGES, q);
+	else
+		queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
+
+	spin_unlock_irq(q->queue_lock);
+	return ret;
+}
+
 
 static struct queue_sysfs_entry queue_requests_entry = {
 	.attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
@@ -170,6 +191,12 @@ static struct queue_sysfs_entry queue_hw_sector_size_entry = {
 	.show = queue_hw_sector_size_show,
 };
 
+static struct queue_sysfs_entry queue_nomerges_entry = {
+	.attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
+	.show = queue_nomerges_show,
+	.store = queue_nomerges_store,
+};
+
 static struct attribute *default_attrs[] = {
 	&queue_requests_entry.attr,
 	&queue_ra_entry.attr,
@@ -177,6 +204,7 @@ static struct attribute *default_attrs[] = {
 	&queue_max_sectors_entry.attr,
 	&queue_iosched_entry.attr,
 	&queue_hw_sector_size_entry.attr,
+	&queue_nomerges_entry.attr,
 	NULL,
 };
 
@@ -207,12 +235,13 @@ queue_attr_store(struct kobject *kobj, struct attribute *attr,
 		    const char *page, size_t length)
 {
 	struct queue_sysfs_entry *entry = to_queue(attr);
-	struct request_queue *q = container_of(kobj, struct request_queue, kobj);
-
+	struct request_queue *q;
 	ssize_t res;
 
 	if (!entry->store)
 		return -EIO;
+
+	q = container_of(kobj, struct request_queue, kobj);
 	mutex_lock(&q->sysfs_lock);
 	if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
 		mutex_unlock(&q->sysfs_lock);
@@ -275,9 +304,12 @@ int blk_register_queue(struct gendisk *disk)
 
 	struct request_queue *q = disk->queue;
 
-	if (!q || !q->request_fn)
+	if (WARN_ON(!q))
 		return -ENXIO;
 
+	if (!q->request_fn)
+		return 0;
+
 	ret = kobject_add(&q->kobj, kobject_get(&disk->dev.kobj),
 			  "%s", "queue");
 	if (ret < 0)
@@ -299,7 +331,10 @@ void blk_unregister_queue(struct gendisk *disk)
 {
 	struct request_queue *q = disk->queue;
 
-	if (q && q->request_fn) {
+	if (WARN_ON(!q))
+		return;
+
+	if (q->request_fn) {
 		elv_unregister_queue(q);
 
 		kobject_uevent(&q->kobj, KOBJ_REMOVE);