From: Thomas Gleixner <tglx@linutronix.de>
To: Vikas Shivappa <vikas.shivappa@linux.intel.com>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org, hpa@zytor.com,
peterz@infradead.org, ravi.v.shankar@intel.com,
vikas.shivappa@intel.com, tony.luck@intel.com,
fenghua.yu@intel.com, andi.kleen@intel.com
Subject: Re: [PATCH 11/21] x86/intel_rdt/cqm: Add mkdir support for RDT monitoring
Date: Sun, 2 Jul 2017 12:58:43 +0200 (CEST) [thread overview]
Message-ID: <alpine.DEB.2.20.1707021213020.2296@nanos> (raw)
In-Reply-To: <1498503368-20173-12-git-send-email-vikas.shivappa@linux.intel.com>
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
next prev parent reply other threads:[~2017-07-02 10:59 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-26 18:55 [PATCH V1 00/21] x86/cqm3: Resctrl based cqm Vikas Shivappa
2017-06-26 18:55 ` [PATCH 01/21] x86/perf/cqm: Wipe out perf " Vikas Shivappa
2017-06-26 18:55 ` [PATCH 02/21] x86/intel_rdt: Fix memory leak during mount Vikas Shivappa
2017-06-30 19:24 ` [tip:x86/urgent] x86/intel_rdt: Fix memory leak on mount failure tip-bot for Vikas Shivappa
2017-06-26 18:55 ` [PATCH 03/21] x86/intel_rdt/cqm: Documentation for resctrl based RDT Monitoring Vikas Shivappa
2017-06-26 18:55 ` [PATCH 04/21] x86/intel_rdt: Introduce a common compile option for RDT Vikas Shivappa
2017-06-26 18:55 ` [PATCH 05/21] x86/intel_rdt: Change file names to accommodate RDT monitor code Vikas Shivappa
2017-06-26 18:55 ` [PATCH 06/21] x86/intel_rdt: Cleanup namespace to support RDT monitoring Vikas Shivappa
2017-06-26 18:55 ` [PATCH 07/21] x86/intel_rdt/cqm: Add RDT monitoring initialization Vikas Shivappa
2017-07-02 9:14 ` Thomas Gleixner
2017-07-06 21:07 ` Shivappa Vikas
2017-06-26 18:55 ` [PATCH 08/21] x86/intel_rdt/cqm: Add RMID(Resource monitoring ID) management Vikas Shivappa
2017-07-02 10:05 ` Thomas Gleixner
2017-07-03 9:55 ` Thomas Gleixner
2017-07-05 15:34 ` Peter Zijlstra
2017-07-05 17:25 ` Thomas Gleixner
2017-07-11 23:54 ` Shivappa Vikas
2017-07-12 20:14 ` Thomas Gleixner
2017-07-05 17:59 ` Tony Luck
2017-07-06 6:51 ` Thomas Gleixner
2017-06-26 18:55 ` [PATCH 09/21] x86/intel_rdt: Simplify info and base file lists Vikas Shivappa
2017-07-02 10:09 ` Thomas Gleixner
2017-07-06 21:09 ` Shivappa Vikas
2017-06-26 18:55 ` [PATCH 10/21] x86/intel_rdt/cqm: Add info files for RDT monitoring Vikas Shivappa
2017-06-26 18:55 ` [PATCH 11/21] x86/intel_rdt/cqm: Add mkdir support " Vikas Shivappa
2017-07-02 10:58 ` Thomas Gleixner [this message]
2017-07-06 21:23 ` Shivappa Vikas
2017-06-26 18:55 ` [PATCH 12/21] x86/intel_rdt/cqm: Add tasks file support Vikas Shivappa
2017-07-02 11:01 ` Thomas Gleixner
2017-07-06 21:25 ` Shivappa Vikas
2017-06-26 18:56 ` [PATCH 13/21] x86/intel_rdt/cqm: Add cpus " Vikas Shivappa
2017-07-02 11:11 ` Thomas Gleixner
2017-07-06 21:26 ` Shivappa Vikas
2017-07-02 12:29 ` Thomas Gleixner
2017-07-06 21:42 ` Shivappa Vikas
2017-07-07 6:44 ` Thomas Gleixner
2017-07-13 18:37 ` Shivappa Vikas
2017-07-13 22:09 ` Shivappa Vikas
2017-06-26 18:56 ` [PATCH 14/21] x86/intel_rdt/cqm: Add mon_data Vikas Shivappa
2017-07-02 12:43 ` Thomas Gleixner
2017-07-06 21:48 ` Shivappa Vikas
2017-07-07 6:22 ` Thomas Gleixner
2017-07-11 21:17 ` Shivappa Vikas
2017-07-11 21:37 ` Luck, Tony
2017-06-26 18:56 ` [PATCH 15/21] x86/intel_rdt/cqm: Add rmdir support Vikas Shivappa
2017-07-02 13:16 ` Thomas Gleixner
2017-07-06 21:49 ` Shivappa Vikas
2017-06-26 18:56 ` [PATCH 16/21] x86/intel_rdt/cqm: Add mount,umount support Vikas Shivappa
2017-07-02 13:22 ` Thomas Gleixner
2017-07-06 21:58 ` Shivappa Vikas
2017-06-26 18:56 ` [PATCH 17/21] x86/intel_rdt/cqm: Add sched_in support Vikas Shivappa
2017-07-02 13:37 ` Thomas Gleixner
2017-07-06 23:35 ` Shivappa Vikas
2017-06-26 18:56 ` [PATCH 18/21] x86/intel_rdt/cqm: Add hotcpu support Vikas Shivappa
2017-06-26 18:56 ` [PATCH 19/21] x86/intel_rdt/mbm: Basic counting of MBM events (total and local) Vikas Shivappa
2017-07-02 13:46 ` Thomas Gleixner
2017-07-06 23:39 ` Shivappa Vikas
2017-07-07 6:47 ` Thomas Gleixner
2017-06-26 18:56 ` [PATCH 20/21] x86/intel_rdt/mbm: Add mbm counter initialization Vikas Shivappa
2017-06-26 18:56 ` [PATCH 21/21] x86/intel_rdt/mbm: Handle counter overflow Vikas Shivappa
2017-07-02 13:57 ` Thomas Gleixner
2017-07-06 23:53 ` Shivappa Vikas
2017-07-07 6:50 ` Thomas Gleixner
2017-07-10 17:54 ` Luck, Tony
2017-07-11 15:22 ` Thomas Gleixner
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