Re: [PATCH] gianfar: reduce stack usage in gianfar_ethtool.c

From: Joe Perches
Date: Tue Aug 09 2011 - 12:08:46 EST


On Tue, 2011-08-09 at 23:45 +0800, stufever@xxxxxxxxx wrote:
> From: Wang Shaoyan <wangshaoyan.pt@xxxxxxxxxx>
> drivers/net/gianfar_ethtool.c:765: warning: the frame size of 2048 bytes is larger than 1024 bytes
[]
> diff --git a/drivers/net/gianfar_ethtool.c b/drivers/net/gianfar_ethtool.c
[]
> @@ -686,10 +686,26 @@ static int gfar_ethflow_to_filer_table(struct gfar_private *priv, u64 ethflow, u
> {
> unsigned int last_rule_idx = priv->cur_filer_idx;
> unsigned int cmp_rqfpr;
> - unsigned int local_rqfpr[MAX_FILER_IDX + 1];
> - unsigned int local_rqfcr[MAX_FILER_IDX + 1];
> + unsigned int *local_rqfpr;
> + unsigned int *local_rqfcr;
> int i = 0x0, k = 0x0;
> int j = MAX_FILER_IDX, l = 0x0;
> + int ret = 1;
> +
> + local_rqfpr = kmalloc(sizeof(unsigned int) * (MAX_FILER_IDX + 1),
> + GFP_KERNEL);
> + if (!local_rqfpr) {
> + pr_err("Out of memory\n");
> + ret = 0;
> + got err;
> + }
> + local_rqfcr = kmalloc(sizeof(unsigned int) * (MAX_FILER_IDX + 1),
> + GFP_KERNEL);
> + if (!local_rqfcr) {
> + pr_err("Out of memory\n");
> + ret = 0;
> + goto err1;
> + }

Perhaps it'd be clearer to use:

local_rqfpr = kmalloc(...)
local_rqfcr = kmalloc(...)
if (!local_rqfpr || !local_rqfcr) {
pr_err(...)
ret = -ENOMEM;
goto err;
}

[...]

err:
kfree(local_rqfpr);
kfree(local_rqfcr);
return ret;

Is the "local_" prefix useful?
It seems like visual noise to me.

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