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SubjectRe: [ckrm-tech] [PATCH 5/7] BC: user interface (syscalls)
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On Tue, 2006-08-29 at 18:55 +0400, Kirill Korotaev wrote:
> Add the following system calls for BC management:
> 1. sys_get_bcid - get current BC id
> 2. sys_set_bcid - change exec_ and fork_ BCs on current
> 3. sys_set_bclimit - set limits for resources consumtions
> 4. sys_get_bcstat - return br_resource_parm on resource
>
> Signed-off-by: Pavel Emelianov <xemul@sw.ru>
> Signed-off-by: Kirill Korotaev <dev@sw.ru>
>
> ---
<snip>

> +
> +asmlinkage long sys_set_bclimit(bcid_t id, unsigned long resource,
> + unsigned long __user *limits)
> +{
> + int error;
> + unsigned long flags;
> + struct beancounter *bc;
> + unsigned long new_limits[2];
> +
> + error = -EPERM;
> + if(!capable(CAP_SYS_RESOURCE))
> + goto out;
> +
> + error = -EINVAL;
> + if (resource >= BC_RESOURCES)
> + goto out;
> +
> + error = -EFAULT;
> + if (copy_from_user(&new_limits, limits, sizeof(new_limits)))
> + goto out;
> +
> + error = -EINVAL;
> + if (new_limits[0] > BC_MAXVALUE || new_limits[1] > BC_MAXVALUE ||
> + new_limits[0] > new_limits[1])
> + goto out;
> +
> + error = -ENOENT;
> + bc = beancounter_findcreate(id, BC_LOOKUP);
> + if (bc == NULL)
> + goto out;

Moving this to be before copy_from_user() would be efficient.
> +
> + spin_lock_irqsave(&bc->bc_lock, flags);
> + bc->bc_parms[resource].barrier = new_limits[0];
> + bc->bc_parms[resource].limit = new_limits[1];
> + spin_unlock_irqrestore(&bc->bc_lock, flags);
> +
> + put_beancounter(bc);
> + error = 0;
> +out:
> + return error;
> +}
<snip>
--

----------------------------------------------------------------------
Chandra Seetharaman | Be careful what you choose....
- sekharan@us.ibm.com | .......you may get it.
----------------------------------------------------------------------

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