On Mon, 26 Jun 2017, Vikas Shivappa wrote:
> +/*
> + * Common code for ctrl_mon and monitor group mkdir.
> + * The caller needs to unlock the global mutex upon success.
> + */
> +static int mkdir_rdt_common(struct kernfs_node *pkn, struct kernfs_node
> *prkn,
pkn and prkn are horrible to distinguish. What's wrong with keeping
*parent_kn and have *kn as the new thing?
> + const char *name, umode_t mode,
> + enum rdt_group_type rtype, struct rdtgroup **r)
> {
Can you please split out that mkdir_rdt_common() change into a separate
patch? It can be done as a preparatory stand alone change just for the
existing rdt group code. Then the monitoring add ons come on top of it.
> - struct rdtgroup *parent, *rdtgrp;
> + struct rdtgroup *prgrp, *rdtgrp;
> struct kernfs_node *kn;
> - int ret, closid;
> -
> - /* Only allow mkdir in the root directory */
> - if (parent_kn != rdtgroup_default.kn)
> - return -EPERM;
> -
> - /* Do not accept '\n' to avoid unparsable situation. */
> - if (strchr(name, '\n'))
> - return -EINVAL;
> + uint fshift = 0;
> + int ret;
>
> - parent = rdtgroup_kn_lock_live(parent_kn);
> - if (!parent) {
> + prgrp = rdtgroup_kn_lock_live(prkn);
> + if (!prgrp) {
> ret = -ENODEV;
> goto out_unlock;
> }
>
> - ret = closid_alloc();
> - if (ret < 0)
> - goto out_unlock;
> - closid = ret;
> -
> /* allocate the rdtgroup. */
> rdtgrp = kzalloc(sizeof(*rdtgrp), GFP_KERNEL);
> if (!rdtgrp) {
> ret = -ENOSPC;
> - goto out_closid_free;
> + goto out_unlock;
> }
> - rdtgrp->closid = closid;
> - list_add(&rdtgrp->rdtgroup_list, &rdt_all_groups);
> + *r = rdtgrp;
> + rdtgrp->parent = prgrp;
> + rdtgrp->type = rtype;
> + INIT_LIST_HEAD(&rdtgrp->crdtgrp_list);
>
> /* kernfs creates the directory for rdtgrp */
> - kn = kernfs_create_dir(parent->kn, name, mode, rdtgrp);
> + kn = kernfs_create_dir(pkn, name, mode, rdtgrp);
> if (IS_ERR(kn)) {
> ret = PTR_ERR(kn);
> goto out_cancel_ref;
> @@ -1138,27 +1166,138 @@ static int rdtgroup_mkdir(struct kernfs_node
> *parent_kn, const char *name,
> if (ret)
> goto out_destroy;
>
> - ret = rdtgroup_add_files(kn, RF_CTRL_BASE);
> + fshift = 1 << (RF_CTRLSHIFT + rtype);
> + ret = rdtgroup_add_files(kn, RFTYPE_BASE | fshift);
I'd rather make this:
files = RFTYPE_BASE | (1U << (RF_CTRLSHIFT + rtype));
ret = rdtgroup_add_files(kn, files);
> if (ret)
> goto out_destroy;
>
> + if (rdt_mon_features) {
> + ret = alloc_rmid();
> + if (ret < 0)
> + return ret;
> +
> + rdtgrp->rmid = ret;
> + }
> kernfs_activate(kn);
>
> - ret = 0;
> - goto out_unlock;
What unlocks prkn now? The caller, right? Please add a comment ...
> + return 0;
>
> out_destroy:
> kernfs_remove(rdtgrp->kn);
> out_cancel_ref:
> - list_del(&rdtgrp->rdtgroup_list);
> kfree(rdtgrp);
> -out_closid_free:
> +out_unlock:
> + rdtgroup_kn_unlock(prkn);
> + return ret;
> +}
> +
> +static void mkdir_rdt_common_clean(struct rdtgroup *rgrp)
> +{
> + kernfs_remove(rgrp->kn);
> + if (rgrp->rmid)
> + free_rmid(rgrp->rmid);
Please put that conditonal into free_rmid().
> + kfree(rgrp);
> +}
> +static int rdtgroup_mkdir(struct kernfs_node *pkn, const char *name,
> + umode_t mode)
> +{
> + /* Do not accept '\n' to avoid unparsable situation. */
> + if (strchr(name, '\n'))
> + return -EINVAL;
> +
> + /*
> + * We don't allow rdtgroup ctrl_mon directories to be created anywhere
> + * except the root directory and dont allow rdtgroup monitor
> + * directories to be created anywhere execept inside mon_groups
> + * directory.
> + */
> + if (rdt_alloc_enabled && pkn == rdtgroup_default.kn)
> + return rdtgroup_mkdir_ctrl_mon(pkn, pkn, name, mode);
> + else if (rdt_mon_features &&
> + !strcmp(pkn->name, "mon_groups"))
> + return rdtgroup_mkdir_mon(pkn, pkn->parent, name, mode);
> + else
> + return -EPERM;
TBH, this is really convoluted (including the comment).
/*
* If the parent directory is the root directory and RDT
* allocation is supported, add a control and monitoring
* subdirectory.
*/
if (rdt_alloc_capable && parent_kn == rdtgroup_default.kn)
return rdtgroup_mkdir_ctrl_mon(...);
/*
* If the parent directory is a monitoring group and RDT
* monitoring is supported, add a monitoring subdirectory.
*/
if (rdt_mon_capable && is_mon_group(parent_kn))
return rdtgroup_mkdir_mon(...);
return -EPERM;
Note, that I did not use strcmp(parent_kn->name) because that's simply
not sufficient. What prevents a user from doing:
# mkdir /sys/fs/resctrl/mon_group/mon_group
# mkdir /sys/fs/resctrl/mon_group/mon_group/foo
You need a better way to distignuish that than strcmp(). You probably want
to prevent creating subdirectories named "mon_group" as well.
Thanks,
tglx
