Clean up some CFS CGroup code

- replace "cont" with "cgrp" in a few places in the CFS cgroup code, 
- use write_uint rather than write for cpu.shares write function

Signed-off-by: Paul Menage <menage@google.com>

---
 kernel/sched.c |   51 +++++++++++++++++----------------------------------
 1 file changed, 17 insertions(+), 34 deletions(-)

Index: container-2.6.23-mm1/kernel/sched.c
===================================================================
--- container-2.6.23-mm1.orig/kernel/sched.c
+++ container-2.6.23-mm1/kernel/sched.c
@@ -6936,25 +6936,25 @@ unsigned long sched_group_shares(struct 
 #ifdef CONFIG_FAIR_CGROUP_SCHED
 
 /* return corresponding task_group object of a cgroup */
-static inline struct task_group *cgroup_tg(struct cgroup *cont)
+static inline struct task_group *cgroup_tg(struct cgroup *cgrp)
 {
-	return container_of(cgroup_subsys_state(cont, cpu_cgroup_subsys_id),
-					 struct task_group, css);
+	return container_of(cgroup_subsys_state(cgrp, cpu_cgroup_subsys_id),
+			    struct task_group, css);
 }
 
 static struct cgroup_subsys_state *
-cpu_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
+cpu_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cgrp)
 {
 	struct task_group *tg;
 
-	if (!cont->parent) {
+	if (!cgrp->parent) {
 		/* This is early initialization for the top cgroup */
-		init_task_group.css.cgroup = cont;
+		init_task_group.css.cgroup = cgrp;
 		return &init_task_group.css;
 	}
 
 	/* we support only 1-level deep hierarchical scheduler atm */
-	if (cont->parent->parent)
+	if (cgrp->parent->parent)
 		return ERR_PTR(-EINVAL);
 
 	tg = sched_create_group();
@@ -6962,21 +6962,21 @@ cpu_cgroup_create(struct cgroup_subsys *
 		return ERR_PTR(-ENOMEM);
 
 	/* Bind the cgroup to task_group object we just created */
-	tg->css.cgroup = cont;
+	tg->css.cgroup = cgrp;
 
 	return &tg->css;
 }
 
 static void cpu_cgroup_destroy(struct cgroup_subsys *ss,
-					struct cgroup *cont)
+			       struct cgroup *cgrp)
 {
-	struct task_group *tg = cgroup_tg(cont);
+	struct task_group *tg = cgroup_tg(cgrp);
 
 	sched_destroy_group(tg);
 }
 
 static int cpu_cgroup_can_attach(struct cgroup_subsys *ss,
-			     struct cgroup *cont, struct task_struct *tsk)
+			     struct cgroup *cgrp, struct task_struct *tsk)
 {
 	/* We don't support RT-tasks being in separate groups */
 	if (tsk->sched_class != &fair_sched_class)
@@ -6986,38 +6986,21 @@ static int cpu_cgroup_can_attach(struct 
 }
 
 static void
-cpu_cgroup_attach(struct cgroup_subsys *ss, struct cgroup *cont,
+cpu_cgroup_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
 			struct cgroup *old_cont, struct task_struct *tsk)
 {
 	sched_move_task(tsk);
 }
 
-static ssize_t cpu_shares_write(struct cgroup *cont, struct cftype *cftype,
-				struct file *file, const char __user *userbuf,
-				size_t nbytes, loff_t *ppos)
+static int cpu_shares_write_uint(struct cgroup *cgrp, struct cftype *cftype,
+				u64 shareval)
 {
-	unsigned long shareval;
-	struct task_group *tg = cgroup_tg(cont);
-	char buffer[2*sizeof(unsigned long) + 1];
-	int rc;
-
-	if (nbytes > 2*sizeof(unsigned long))	/* safety check */
-		return -E2BIG;
-
-	if (copy_from_user(buffer, userbuf, nbytes))
-		return -EFAULT;
-
-	buffer[nbytes] = 0;	/* nul-terminate */
-	shareval = simple_strtoul(buffer, NULL, 10);
-
-	rc = sched_group_set_shares(tg, shareval);
-
-	return (rc < 0 ? rc : nbytes);
+	return sched_group_set_shares(cgroup_tg(cgrp), shareval);
 }
 
-static u64 cpu_shares_read_uint(struct cgroup *cont, struct cftype *cft)
+static u64 cpu_shares_read_uint(struct cgroup *cgrp, struct cftype *cft)
 {
-	struct task_group *tg = cgroup_tg(cont);
+	struct task_group *tg = cgroup_tg(cgrp);
 
 	return (u64) tg->shares;
 }
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On Mon, Oct 22, 2007 at 05:49:20PM -0700, Paul Menage wrote:
> Clean up some CFS CGroup code
> 
> - replace "cont" with "cgrp" in a few places in the CFS cgroup code, 

This change looks good to me. Thanks for doing it.

> - use write_uint rather than write for cpu.shares write function

Minor nit: From pov of making this patch series git bisect safe, shouldn't we 
be registering a write_uint() handler in this patch as well?
 
-- 
Regards,
vatsa
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On 10/22/07, Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> wrote:
>
> Minor nit: From pov of making this patch series git bisect safe, shouldn't we
> be registering a write_uint() handler in this patch as well?
>

Yes, we should. Sigh. I originally had the cleanup and the new
reporting interface in the same patch, and decided to split them apart
into a cleanup patch and a new feature patch, but clearly goofed. I'll
resend tomorrow with the write_uint registration in the right place.

Paul
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On 10/22/07, Paul Menage <menage@google.com> wrote:
> On 10/22/07, Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> wrote:
> >
> > Minor nit: From pov of making this patch series git bisect safe, shouldn't we
> > be registering a write_uint() handler in this patch as well?
> >
>
> Yes, we should. Sigh. I originally had the cleanup and the new
> reporting interface in the same patch, and decided to split them apart
> into a cleanup patch and a new feature patch, but clearly goofed. I'll
> resend tomorrow with the write_uint registration in the right place.

OK, this wasn't a patch goof - the original patch in my tree does have
the addition of write_uint in the cftype definition. I guess the last
hunk got lost as I transferred it to the email.

Paul
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