[PATCH 12/13] ll_rw_blk: temporarily enable max_segments tweaking

Jens Axboe
2007-05-10T10:25:43Z

Expose this setting for now, so that users can play with enabling
large commands without defaulting it to on globally.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
---
block/ll_rw_blk.c | 22 ++++++++++++++++++++++
1 files changed, 22 insertions(+), 0 deletions(-)

diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index b01a5f2..cf05396 100644
--- a/block/ll_rw_blk.c
+++ b/block/ll_rw_blk.c
@@ -3930,7 +3930,22 @@ 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_max_segments_show(struct request_queue *q, char *page)
+{
+ return queue_var_show(q->max_phys_segments, page);
+}
+
+static ssize_t queue_max_segments_store(struct request_queue *q, const char *page, size_t count)
+{
+ unsigned long segments;
+ ssize_t ret = queue_var_store(&segments, page, count);

+ spin_lock_irq(q->queue_lock);
+ q->max_phys_segments = segments;
+ 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 },
.show = queue_requests_show,
@@ -3954,6 +3969,12 @@ static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
.show = queue_max_hw_sectors_show,
};

+static struct queue_sysfs_entry queue_max_segments_entry = {
+ .attr = {.name = "max_segments", .mode = S_IRUGO |S_IWUSR },
+ .show = queue_max_segments_show,
+ .store = queue_max_segments_store,
+};
+
static struct queue_sysfs_entry queue_iosched_entry = {
.attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
.show = elv_iosched_show,
@@ -3965,6 +3986,7 @@ static struct attribute *default_attrs[] = {
&queue_ra_entry.attr,
&queue_max_hw_sectors_entry.attr,
&queue_max_sectors_entry.attr,
+ &queue_max_segments_entry.attr,
&queue_iosched_entry.attr,
NULL,
};
--
1.5.2.rc1