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SubjectRe: [RFC][-mm PATCH 1/8] Memory controller resource counters (v3)
On 7/20/07, Balbir Singh <balbir@linux.vnet.ibm.com> wrote:
> +
> +ssize_t res_counter_read(struct res_counter *counter, int member,
> + const char __user *userbuf, size_t nbytes, loff_t *pos)
> +{
> + unsigned long *val;
> + char buf[64], *s;
> +
> + s = buf;
> + val = res_counter_member(counter, member);
> + s += sprintf(s, "%lu\n", *val);
> + return simple_read_from_buffer((void __user *)userbuf, nbytes,
> + pos, buf, s - buf);
> +}

I think it should be possible to use the support built-in to task
containers to export a uint64 rather than having to create a separate
function here.

> +
> +ssize_t res_counter_write(struct res_counter *counter, int member,
> + const char __user *userbuf, size_t nbytes, loff_t *pos)
> +{
> + int ret;
> + char *buf, *end;
> + unsigned long tmp, *val;
> +
> + buf = kmalloc(nbytes + 1, GFP_KERNEL);
> + ret = -ENOMEM;
> + if (buf == NULL)
> + goto out;
> +
> + buf[nbytes] = '\0';
> + ret = -EFAULT;
> + if (copy_from_user(buf, userbuf, nbytes))
> + goto out_free;
> +
> + ret = -EINVAL;
> + tmp = simple_strtoul(buf, &end, 10);
> + if (*end != '\0')
> + goto out_free;
> +
> + val = res_counter_member(counter, member);
> + *val = tmp;
> + ret = nbytes;
> +out_free:
> + kfree(buf);
> +out:
> + return ret;
> +}

I should probably add a generic "write uint64" wraper to task
containers as well.

Paul
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