[PATCH 5/9] aoe: support larger I/O requests via aoe_maxsectors module param

From: Ed Cashin
Date: Mon Oct 15 2012 - 21:48:37 EST


The GPFS filesystem is an example of an aoe user that requires the
aoe driver to support I/O request sizes larger than the default.
Most users will not need large I/O request sizes, because they would
need to be split up into multiple AoE commands anyway.

Signed-off-by: Ed Cashin <ecashin@xxxxxxxxxx>
---
drivers/block/aoe/aoeblk.c | 9 +++++++++
1 files changed, 9 insertions(+), 0 deletions(-)

diff --git a/drivers/block/aoe/aoeblk.c b/drivers/block/aoe/aoeblk.c
index 00dfc50..d5aa3b8 100644
--- a/drivers/block/aoe/aoeblk.c
+++ b/drivers/block/aoe/aoeblk.c
@@ -16,11 +16,18 @@
#include <linux/netdevice.h>
#include <linux/mutex.h>
#include <linux/export.h>
+#include <linux/moduleparam.h>
#include "aoe.h"

static DEFINE_MUTEX(aoeblk_mutex);
static struct kmem_cache *buf_pool_cache;

+/* GPFS needs a larger value than the default. */
+static int aoe_maxsectors;
+module_param(aoe_maxsectors, int, 0644);
+MODULE_PARM_DESC(aoe_maxsectors,
+ "When nonzero, set the maximum number of sectors per I/O request");
+
static ssize_t aoedisk_show_state(struct device *dev,
struct device_attribute *attr, char *page)
{
@@ -248,6 +255,8 @@ aoeblk_gdalloc(void *vp)
d->blkq = gd->queue = q;
q->queuedata = d;
d->gd = gd;
+ if (aoe_maxsectors)
+ blk_queue_max_hw_sectors(q, aoe_maxsectors);
gd->major = AOE_MAJOR;
gd->first_minor = d->sysminor;
gd->fops = &aoe_bdops;
--
1.7.1

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