From: Thomas Gleixner <tglx@linutronix.de>
To: Fenghua Yu <fenghua.yu@intel.com>
Cc: "H. Peter Anvin" <h.peter.anvin@intel.com>,
Ingo Molnar <mingo@elte.hu>, Tony Luck <tony.luck@intel.com>,
Peter Zijlstra <peterz@infradead.org>, Tejun Heo <tj@kernel.org>,
Borislav Petkov <bp@suse.de>,
Stephane Eranian <eranian@google.com>,
Marcelo Tosatti <mtosatti@redhat.com>,
David Carrillo-Cisneros <davidcc@google.com>,
Shaohua Li <shli@fb.com>,
Ravi V Shankar <ravi.v.shankar@intel.com>,
Vikas Shivappa <vikas.shivappa@linux.intel.com>,
Sai Prakhya <sai.praneeth.prakhya@intel.com>,
linux-kernel <linux-kernel@vger.kernel.org>, x86 <x86@kernel.org>
Subject: Re: [PATCH v2 27/33] x86/intel_rdt_rdtgroup.c: Implement resctrl file system commands
Date: Thu, 8 Sep 2016 22:09:09 +0200 (CEST) [thread overview]
Message-ID: <alpine.DEB.2.20.1609082141220.5454@nanos> (raw)
In-Reply-To: <1473328647-33116-28-git-send-email-fenghua.yu@intel.com>
On Thu, 8 Sep 2016, Fenghua Yu wrote:
> +static struct kernfs_syscall_ops rdtgroup_kf_syscall_ops = {
> + .mkdir = rdtgroup_mkdir,
> + .rmdir = rdtgroup_rmdir,
> +};
> +
> +static struct file_system_type rdt_fs_type = {
> + .name = "resctrl",
> + .mount = rdt_mount,
> + .kill_sb = rdt_kill_sb,
> +};
So the above struct is nicely aligned and readable. While this one is
not. Sigh,
> struct rdtgroup *root_rdtgrp;
> static struct rftype rdtgroup_partition_base_files[];
> struct cache_domain cache_domains[MAX_CACHE_LEAVES];
> /* The default hierarchy. */
> struct rdtgroup_root rdtgrp_dfl_root;
> static struct list_head rdtgroups;
> +bool rdtgroup_mounted;
Your choice of global/static visible variables is driven by a random
generator or what?
> /*
> * kernfs_root - find out the kernfs_root a kernfs_node belongs to
> @@ -730,6 +749,110 @@ static void rdtgroup_destroy_locked(struct rdtgroup *rdtgrp)
> kernfs_remove(rdtgrp->kn);
> }
>
> +static int rdtgroup_mkdir(struct kernfs_node *parent_kn, const char *name,
> + umode_t mode)
> +{
> + struct rdtgroup *parent, *rdtgrp;
> + struct rdtgroup_root *root;
> + struct kernfs_node *kn;
> + int ret;
> +
> + if (parent_kn != root_rdtgrp->kn)
> + return -EPERM;
> +
> + /* Do not accept '\n' to avoid unparsable situation.
> + */
Where did copy you this comment style from? Its' horrible and here is a
lengthy explanation why: https://lkml.org/lkml/2016/7/8/625
> +static struct dentry *rdt_mount(struct file_system_type *fs_type,
> + int flags, const char *unused_dev_name,
> + void *data)
> +{
> + struct super_block *pinned_sb = NULL;
> + struct rdtgroup_root *root;
> + struct dentry *dentry;
> + int ret;
> + bool new_sb;
> +
> + /*
> + * The first time anyone tries to mount a rdtgroup, enable the list
> + * linking tasks and fix up all existing tasks.
What are 'list linking tasks'? What is fixed up here?
> + */
> + if (rdtgroup_mounted)
> + return ERR_PTR(-EBUSY);
How is this serialized against concurrent mounts? Oh well....
> + rdt_opts.cdp_enabled = false;
> + rdt_opts.verbose = false;
> + cdp_enabled = false;
> +
> + ret = parse_rdtgroupfs_options(data);
> + if (ret)
> + goto out_mount;
> +
> + if (rdt_opts.cdp_enabled) {
> + cdp_enabled = true;
> + cconfig.max_closid >>= cdp_enabled;
> + pr_info("CDP is enabled\n");
> + }
> +
> + init_msrs(cdp_enabled);
> +
> + root = &rdtgrp_dfl_root;
> +
> + ret = get_default_resources(&root->rdtgrp);
> + if (ret)
> + return ERR_PTR(-ENOSPC);
> +
> +out_mount:
> + dentry = kernfs_mount(fs_type, flags, root->kf_root,
> + RDTGROUP_SUPER_MAGIC,
> + &new_sb);
> + if (IS_ERR(dentry) || !new_sb)
> + goto out_unlock;
And ret , which is returned @out_unlock is 0. So instead of returning the
error code encoded in dentry you return a NULL pointer.
> + /*
> + * If @pinned_sb, we're reusing an existing root and holding an
> + * extra ref on its sb. Mount is complete. Put the extra ref.
> + */
> + if (pinned_sb) {
And how exactly becomes pinned_sb != NULL?
> + WARN_ON(new_sb);
> + deactivate_super(pinned_sb);
> + }
Not at all.
> + INIT_LIST_HEAD(&root->rdtgrp.pset.tasks);
> +
> + cpumask_copy(&root->rdtgrp.cpu_mask, cpu_online_mask);
> + static_key_slow_inc(&rdt_enable_key);
> + rdtgroup_mounted = true;
> +
> + return dentry;
> +
> +out_unlock:
> + return ERR_PTR(ret);
So a return magically unlocks stuff. Or does this happen in ERR_PTR()?
This jump label is not only pointless it's also named badly.
Thanks,
tglx
next prev parent reply other threads:[~2016-09-08 20:11 UTC|newest]
Thread overview: 96+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-08 9:56 [PATCH v2 00/33] Enable Intel Resource Allocation in Resource Director Technology Fenghua Yu
2016-09-08 9:56 ` [PATCH v2 01/33] cacheinfo: Introduce cache id Fenghua Yu
2016-09-09 15:01 ` Nilay Vaish
2016-09-08 9:56 ` [PATCH v2 02/33] Documentation, ABI: Add a document entry for " Fenghua Yu
2016-09-08 19:33 ` Thomas Gleixner
2016-09-09 15:11 ` Nilay Vaish
2016-09-08 9:56 ` [PATCH v2 03/33] x86, intel_cacheinfo: Enable cache id in x86 Fenghua Yu
2016-09-08 9:56 ` [PATCH v2 04/33] drivers/base/cacheinfo.c: Export some cacheinfo functions for others to use Fenghua Yu
2016-09-08 8:21 ` Thomas Gleixner
2016-09-08 9:56 ` [PATCH v2 05/33] x86/intel_rdt: Cache Allocation documentation Fenghua Yu
2016-09-08 9:57 ` [PATCH v2 06/33] Documentation, x86: Documentation for Intel resource allocation user interface Fenghua Yu
2016-09-08 11:22 ` Borislav Petkov
2016-09-08 22:01 ` Shaohua Li
2016-09-09 1:17 ` Fenghua Yu
2016-09-08 22:45 ` Shaohua Li
2016-09-09 7:22 ` Fenghua Yu
2016-09-09 17:50 ` Shaohua Li
2016-09-09 18:03 ` Luck, Tony
2016-09-09 21:43 ` Shaohua Li
2016-09-09 21:59 ` Luck, Tony
2016-09-10 0:36 ` Yu, Fenghua
2016-09-12 4:15 ` Shaohua Li
2016-09-13 13:27 ` Thomas Gleixner
2016-09-08 9:57 ` [PATCH v2 07/33] x86/intel_rdt: Add support for Cache Allocation detection Fenghua Yu
2016-09-08 11:50 ` Borislav Petkov
2016-09-08 16:53 ` Yu, Fenghua
2016-09-08 17:17 ` Borislav Petkov
2016-09-08 13:17 ` Thomas Gleixner
2016-09-08 13:59 ` Yu, Fenghua
2016-09-13 22:40 ` Dave Hansen
2016-09-13 22:52 ` Luck, Tony
2016-09-13 23:00 ` Dave Hansen
2016-09-08 9:57 ` [PATCH v2 08/33] x86/intel_rdt: Add Class of service management Fenghua Yu
2016-09-08 8:56 ` Thomas Gleixner
2016-09-12 16:02 ` Nilay Vaish
2016-09-08 9:57 ` [PATCH v2 09/33] x86/intel_rdt: Add L3 cache capacity bitmask management Fenghua Yu
2016-09-08 9:40 ` Thomas Gleixner
2016-09-12 16:10 ` Nilay Vaish
2016-09-08 9:57 ` [PATCH v2 10/33] x86/intel_rdt: Implement scheduling support for Intel RDT Fenghua Yu
2016-09-08 9:53 ` Thomas Gleixner
2016-09-15 21:36 ` Yu, Fenghua
2016-09-15 21:40 ` Luck, Tony
2016-09-13 17:55 ` Nilay Vaish
2016-09-08 9:57 ` [PATCH v2 11/33] x86/intel_rdt: Hot cpu support for Cache Allocation Fenghua Yu
2016-09-08 10:03 ` Thomas Gleixner
2016-09-13 18:18 ` Nilay Vaish
2016-09-13 19:10 ` Luck, Tony
2016-09-08 9:57 ` [PATCH v2 12/33] x86/intel_rdt: Intel haswell Cache Allocation enumeration Fenghua Yu
2016-09-08 10:08 ` Thomas Gleixner
2016-09-08 9:57 ` [PATCH v2 13/33] Define CONFIG_INTEL_RDT Fenghua Yu
2016-09-08 10:14 ` Thomas Gleixner
2016-09-08 9:57 ` [PATCH v2 14/33] x86/intel_rdt: Intel Code Data Prioritization detection Fenghua Yu
2016-09-08 9:57 ` [PATCH v2 15/33] x86/intel_rdt: Adds support to enable Code Data Prioritization Fenghua Yu
2016-09-08 10:18 ` Thomas Gleixner
2016-09-08 9:57 ` [PATCH v2 16/33] x86/intel_rdt: Class of service and capacity bitmask management for CDP Fenghua Yu
2016-09-08 10:29 ` Thomas Gleixner
2016-09-08 9:57 ` [PATCH v2 17/33] x86/intel_rdt: Hot cpu update for code data prioritization Fenghua Yu
2016-09-08 10:34 ` Thomas Gleixner
2016-09-08 9:57 ` [PATCH v2 18/33] sched.h: Add rg_list and rdtgroup in task_struct Fenghua Yu
2016-09-08 10:36 ` Thomas Gleixner
2016-09-08 9:57 ` [PATCH v2 19/33] magic number for resctrl file system Fenghua Yu
2016-09-08 10:41 ` Thomas Gleixner
2016-09-08 10:47 ` Borislav Petkov
2016-09-08 9:57 ` [PATCH v2 20/33] x86/intel_rdt.h: Header for inter_rdt.c Fenghua Yu
2016-09-08 12:36 ` Thomas Gleixner
2016-09-08 9:57 ` [PATCH v2 21/33] x86/intel_rdt_rdtgroup.h: Header for user interface Fenghua Yu
2016-09-08 12:44 ` Thomas Gleixner
2016-09-08 9:57 ` [PATCH v2 22/33] x86/intel_rdt.c: Extend RDT to per cache and per resources Fenghua Yu
2016-09-08 14:57 ` Thomas Gleixner
2016-09-13 22:54 ` Dave Hansen
2016-09-08 9:57 ` [PATCH v2 23/33] x86/intel_rdt_rdtgroup.c: User interface for RDT Fenghua Yu
2016-09-08 14:59 ` Thomas Gleixner
2016-09-08 9:57 ` [PATCH v2 24/33] x86/intel_rdt_rdtgroup.c: Create info directory Fenghua Yu
2016-09-08 16:04 ` Thomas Gleixner
2016-09-08 9:57 ` [PATCH v2 25/33] include/linux/resctrl.h: Define fork and exit functions in a new header file Fenghua Yu
2016-09-08 16:07 ` Thomas Gleixner
2016-09-08 9:57 ` [PATCH v2 26/33] Task fork and exit for rdtgroup Fenghua Yu
2016-09-08 19:41 ` Thomas Gleixner
2016-09-13 23:13 ` Dave Hansen
2016-09-13 23:35 ` Luck, Tony
2016-09-14 14:28 ` Dave Hansen
2016-09-08 9:57 ` [PATCH v2 27/33] x86/intel_rdt_rdtgroup.c: Implement resctrl file system commands Fenghua Yu
2016-09-08 20:09 ` Thomas Gleixner [this message]
2016-09-08 22:04 ` Shaohua Li
2016-09-09 1:23 ` Fenghua Yu
2016-09-08 9:57 ` [PATCH v2 28/33] x86/intel_rdt_rdtgroup.c: Read and write cpus Fenghua Yu
2016-09-08 20:25 ` Thomas Gleixner
2016-09-08 9:57 ` [PATCH v2 29/33] x86/intel_rdt_rdtgroup.c: Tasks iterator and write Fenghua Yu
2016-09-08 20:50 ` Thomas Gleixner
2016-09-08 9:57 ` [PATCH v2 30/33] x86/intel_rdt_rdtgroup.c: Process schemata input from resctrl interface Fenghua Yu
2016-09-08 22:20 ` Thomas Gleixner
2016-09-08 9:57 ` [PATCH v2 31/33] Documentation/kernel-parameters: Add kernel parameter "resctrl" for CAT Fenghua Yu
2016-09-08 22:25 ` Thomas Gleixner
2016-09-08 9:57 ` [PATCH v2 32/33] MAINTAINERS: Add maintainer for Intel RDT resource allocation Fenghua Yu
2016-09-08 9:57 ` [PATCH v2 33/33] x86/Makefile: Build intel_rdt_rdtgroup.c Fenghua Yu
2016-09-08 23:59 ` Thomas Gleixner
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