Re: [PATCH 08/18] io-controller: idle for sometime on sync queuebefore expiring it

From: Gui Jianfeng
Date: Tue Jun 09 2009 - 03:58:29 EST


Vivek Goyal wrote:
...
> +ssize_t elv_fairness_store(struct request_queue *q, const char *name,
> + size_t count)
> +{
> + struct elv_fq_data *efqd;
> + unsigned int data;
> + unsigned long flags;
> +
> + char *p = (char *)name;
> +
> + data = simple_strtoul(p, &p, 10);
> +
> + if (data < 0)
> + data = 0;
> + else if (data > INT_MAX)
> + data = INT_MAX;

Hi Vivek,

data might overflow on 64 bit systems. In addition, since "fairness" is nothing
more than a switch, just let it be.

Signed-off-by: Gui Jianfeng <guijianfeng@xxxxxxxxxxxxxx>
---
block/elevator-fq.c | 10 +++++-----
block/elevator-fq.h | 2 +-
2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/block/elevator-fq.c b/block/elevator-fq.c
index 655162b..42d4279 100644
--- a/block/elevator-fq.c
+++ b/block/elevator-fq.c
@@ -2605,7 +2605,7 @@ static inline int is_root_group_ioq(struct request_queue *q,
ssize_t elv_fairness_show(struct request_queue *q, char *name)
{
struct elv_fq_data *efqd;
- unsigned int data;
+ unsigned long data;
unsigned long flags;

spin_lock_irqsave(q->queue_lock, flags);
@@ -2619,17 +2619,17 @@ ssize_t elv_fairness_store(struct request_queue *q, const char *name,
size_t count)
{
struct elv_fq_data *efqd;
- unsigned int data;
+ unsigned long data;
unsigned long flags;

char *p = (char *)name;

data = simple_strtoul(p, &p, 10);

- if (data < 0)
+ if (!data)
data = 0;
- else if (data > INT_MAX)
- data = INT_MAX;
+ else
+ data = 1;

spin_lock_irqsave(q->queue_lock, flags);
efqd = &q->elevator->efqd;
diff --git a/block/elevator-fq.h b/block/elevator-fq.h
index b2bb11a..4fe843a 100644
--- a/block/elevator-fq.h
+++ b/block/elevator-fq.h
@@ -359,7 +359,7 @@ struct elv_fq_data {
* throughput and focus more on providing fairness for sync
* queues.
*/
- int fairness;
+ unsigned long fairness;
};

extern int elv_slice_idle;
--
1.5.4.rc3


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