2.6.26-rc1

 block

diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index 54d0db1..e85c401 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -135,6 +135,25 @@ 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);
+
+   if (nm)
+          set_bit(QUEUE_FLAG_NOMERGES, &q->queue_flags);
+   else
+          clear_bit(QUEUE_FLAG_NOMERGES, &q->queue_flags);
+
+   return ret;
+}
+
 
 static struct queue_sysfs_entry queue_requests_entry = {
    .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
@@ -170,6 +189,12 @@ 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 +202,7 @@ 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,
 };
 
@@ -276,9 +302,12 @@ 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)
@@ -300,7 +329,10 @@ 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);