From: ebiederm@xmission.com (Eric W. Biederman)
To: Lucian Adrian Grijincu <lucian.grijincu@gmail.com>
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
netdev@vger.kernel.org,
Damien Millescamps <damien.millescamps@6wind.com>
Subject: Re: [PATCH 18/29] sysctl: Normalize the root_table data structure.
Date: Sun, 29 Jan 2012 16:22:49 -0800 [thread overview]
Message-ID: <m1pqe2jaxy.fsf@fess.ebiederm.org> (raw)
In-Reply-To: <CAPLs8y9-nA7gZymMkFzOdB6zh0h2hS+dhWu42ciOaHzJ++Z+gg@mail.gmail.com> (Lucian Adrian Grijincu's message of "Sun, 29 Jan 2012 19:36:06 +0200")
Lucian thanks for the review.
Lucian Adrian Grijincu <lucian.grijincu@gmail.com> writes:
> On Fri, Jan 27, 2012 at 6:51 AM, Eric W. Biederman
> <ebiederm@xmission.com> wrote:
>> Every other directory has a .child member and we look at the .child
>> for our entries. Do the same for the root_table.
>>
>> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
>> ---
>> fs/proc/proc_sysctl.c | 15 +++++++++++----
>> 1 files changed, 11 insertions(+), 4 deletions(-)
>>
>> diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
>> index 7e96a26..88d1b06 100644
>> --- a/fs/proc/proc_sysctl.c
>> +++ b/fs/proc/proc_sysctl.c
>> @@ -25,7 +25,14 @@ void proc_sys_poll_notify(struct ctl_table_poll *poll)
>> wake_up_interruptible(&poll->wait);
>> }
>>
>> -static struct ctl_table root_table[1];
>> +static struct ctl_table root_table[] = {
>> + {
>> + .procname = "",
>> + .mode = S_IRUGO|S_IXUGO,
>
> Why not: .mode = S_IFDIR|S_IRUGO|S_IXUGO ?
>
> You change it later and add IFDIR in patch 22/29 because of this
> change (from 22/29):
> - if (!table->child) {
> + if (!S_ISDIR(table->mode)) {
>
> but if might as well be done here.
Actually doing not adding S_IFDIR here is important for keeping the
notion of changing one logical thing at a time.
I see normalizing this table early as deliberately emphasizing that we
started using S_IFDIR later.
>> + .child = &root_table[1],
>> + },
>> + { }
>> +};
>> static struct ctl_table_root sysctl_table_root;
>> static struct ctl_table_header root_table_header = {
>> {{.count = 1,
>> @@ -319,7 +326,7 @@ static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry,
>> goto out;
>> }
>
> Somewhere above we have
> struct ctl_table *table = PROC_I(inode)->sysctl_entry;
> and sysctl_entry can take two values:
> - NULL: fs/proc/inode.c:proc_alloc_inode()
> - a non-NULL table in: proc_sys_make_inode()
>
> The only inode that can be passed to proc_sys_lookup that can have
> table=NULL is the root inode.
> In that case head will be &root_table_header.
>
>
> So head->ctl_table[1] == root_table_header.ctl_table[1] == root_table[1].
Yes.
>> - table = table ? table->child : head->ctl_table;
>> + table = table ? table->child : &head->ctl_table[1];
>
> I think this could be improved to something like this:
> /* table == NULL only for the procfs root directory */
> table = table ? table->child : &root_table[1];
>
>
> It's not that important, as this code will go away in a few patches.
Good catch. I had to ask myself after I read this why the code wasn't
pointing at root_table already. The answer as it turns out was because
it was static in kernel/sysctl.c until my earlier patches and I simply
missed the opportunity.
>> p = find_in_table(table, name);
>> if (!p) {
>> @@ -510,7 +517,7 @@ static int proc_sys_readdir(struct file *filp, void *dirent, filldir_t filldir)
>> goto out;
>> }
>>
>> - table = table ? table->child : head->ctl_table;
>> + table = table ? table->child : &head->ctl_table[1];
>
> Similar.
Agreed. At this point in the game since this code does go away I don't
think it is worth making the change now. But I will keep it in mind
and I you have definitely spotted an opportunity missed in this
patchset.
Eric
next prev parent reply other threads:[~2012-01-30 0:20 UTC|newest]
Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-27 4:45 [Review][PATCH][0/29] sysctl rewrite for speed and clarity Eric W. Biederman
2012-01-27 4:49 ` [PATCH 01/29] sysctl: remove impossible condition check Eric W. Biederman
2012-01-27 4:49 ` [PATCH 02/29] sysctl: Consolidate !CONFIG_SYSCTL handling Eric W. Biederman
2012-01-27 4:49 ` [PATCH 03/29] sysctl: Register the base sysctl table like any other sysctl table Eric W. Biederman
2012-01-27 4:49 ` [PATCH 04/29] sysctl: Move the implementation into fs/proc/proc_sysctl.c Eric W. Biederman
2012-01-27 4:49 ` [PATCH 05/29] sysctl: Make the directories have nlink == 1 Eric W. Biederman
2012-01-27 4:49 ` [PATCH 06/29] sysctl: Implement retire_sysctl_set Eric W. Biederman
2012-01-27 4:49 ` [PATCH 07/29] sysctl: Remove the unnecessary sysctl_set parent concept Eric W. Biederman
2012-01-27 4:49 ` [PATCH 08/29] sysctl: Create local copies of directory names used in paths Eric W. Biederman
2012-01-27 4:49 ` [PATCH 09/29] sysctl: Add support for register sysctl tables with a normal cstring path Eric W. Biederman
2012-01-27 4:49 ` [PATCH 10/29] sysctl: Add ctl_table chains into cstring paths Eric W. Biederman
2012-01-27 4:49 ` [PATCH 11/29] sysctl: register only tables of sysctl files Eric W. Biederman
2012-01-27 4:49 ` [PATCH 12/29] sysctl: Improve the sysctl sanity checks Eric W. Biederman
2012-01-27 4:49 ` [PATCH 13/29] sysctl: Remove the now unused ctl_table parent field Eric W. Biederman
2012-01-27 4:49 ` [PATCH 14/29] sysctl: A more obvious version of grab_header Eric W. Biederman
2012-01-27 4:49 ` [PATCH 15/29] sysctl: Initial support for auto-unregistering sysctl tables Eric W. Biederman
2012-01-27 4:49 ` [PATCH 16/29] sysctl: Factor out init_header from __register_sysctl_paths Eric W. Biederman
2012-01-27 4:49 ` [PATCH 17/29] sysctl: Factor out insert_header and erase_header Eric W. Biederman
2012-01-27 4:49 ` [PATCH 18/29] sysctl: Normalize the root_table data structure Eric W. Biederman
2012-01-27 4:50 ` [PATCH 19/29] sysctl: Rewrite proc_sys_lookup introducing find_entry and lookup_entry Eric W. Biederman
2012-01-27 4:50 ` [PATCH 20/29] sysctl: Rewrite proc_sys_readdir in terms of first_entry and next_entry Eric W. Biederman
2012-01-27 4:50 ` [PATCH 21/29] sysctl: Add a root pointer to ctl_table_set Eric W. Biederman
2012-01-27 4:50 ` [PATCH 22/29] sysctl: Stop requiring explicit management of sysctl directories Eric W. Biederman
2012-01-27 4:50 ` [PATCH 23/29] sysctl: Add sysctl_print_dir and use it in get_subdir Eric W. Biederman
2012-01-27 4:50 ` [PATCH 24/29] sysctl: Replace root_list with links between sysctl_table_sets Eric W. Biederman
2012-01-27 4:50 ` [PATCH 25/29] sysctl: Modify __register_sysctl_paths to take a set instead of a root and an nsproxy Eric W. Biederman
2012-01-27 4:50 ` [PATCH 26/29] sysctl: Move sysctl_check_dups into insert_header Eric W. Biederman
2012-01-27 4:50 ` [PATCH 27/29] sysctl: Make the header lists per directory Eric W. Biederman
2012-01-27 4:50 ` [PATCH 28/29] sysctl: Index sysctl directories with rbtrees Eric W. Biederman
2012-01-27 4:50 ` [PATCH 29/29] sysctl: Add register_sysctl for normal sysctl users Eric W. Biederman
2012-01-27 4:51 ` [PATCH 01/29] sysctl: remove impossible condition check Eric W. Biederman
2012-01-27 4:51 ` [PATCH 02/29] sysctl: Consolidate !CONFIG_SYSCTL handling Eric W. Biederman
2012-01-27 4:51 ` [PATCH 03/29] sysctl: Register the base sysctl table like any other sysctl table Eric W. Biederman
2012-01-27 4:51 ` [PATCH 04/29] sysctl: Move the implementation into fs/proc/proc_sysctl.c Eric W. Biederman
2012-01-27 4:51 ` [PATCH 05/29] sysctl: Make the directories have nlink == 1 Eric W. Biederman
2012-01-27 4:51 ` [PATCH 06/29] sysctl: Implement retire_sysctl_set Eric W. Biederman
2012-01-27 4:51 ` [PATCH 07/29] sysctl: Remove the unnecessary sysctl_set parent concept Eric W. Biederman
2012-01-27 4:51 ` [PATCH 08/29] sysctl: Create local copies of directory names used in paths Eric W. Biederman
2012-01-27 4:51 ` [PATCH 09/29] sysctl: Add support for register sysctl tables with a normal cstring path Eric W. Biederman
2012-01-27 4:51 ` [PATCH 10/29] sysctl: Add ctl_table chains into cstring paths Eric W. Biederman
2012-01-27 4:51 ` [PATCH 11/29] sysctl: register only tables of sysctl files Eric W. Biederman
2012-01-27 4:51 ` [PATCH 12/29] sysctl: Improve the sysctl sanity checks Eric W. Biederman
2012-01-27 4:51 ` [PATCH 13/29] sysctl: Remove the now unused ctl_table parent field Eric W. Biederman
2012-01-27 4:51 ` [PATCH 14/29] sysctl: A more obvious version of grab_header Eric W. Biederman
2012-01-27 4:51 ` [PATCH 15/29] sysctl: Initial support for auto-unregistering sysctl tables Eric W. Biederman
2012-01-27 4:51 ` [PATCH 16/29] sysctl: Factor out init_header from __register_sysctl_paths Eric W. Biederman
2012-01-27 4:51 ` [PATCH 17/29] sysctl: Factor out insert_header and erase_header Eric W. Biederman
2012-01-27 4:51 ` [PATCH 18/29] sysctl: Normalize the root_table data structure Eric W. Biederman
2012-01-29 17:36 ` Lucian Adrian Grijincu
2012-01-30 0:22 ` Eric W. Biederman [this message]
2012-01-27 4:51 ` [PATCH 19/29] sysctl: Rewrite proc_sys_lookup introducing find_entry and lookup_entry Eric W. Biederman
2012-01-29 15:49 ` Lucian Adrian Grijincu
2012-01-27 4:51 ` [PATCH 20/29] sysctl: Rewrite proc_sys_readdir in terms of first_entry and next_entry Eric W. Biederman
2012-01-27 4:51 ` [PATCH 21/29] sysctl: Add a root pointer to ctl_table_set Eric W. Biederman
2012-01-29 17:19 ` Lucian Adrian Grijincu
2012-01-27 4:51 ` [PATCH 22/29] sysctl: Stop requiring explicit management of sysctl directories Eric W. Biederman
2012-01-29 19:31 ` Lucian Adrian Grijincu
2012-01-31 4:45 ` Eric W. Biederman
2012-01-27 4:51 ` [PATCH 23/29] sysctl: Add sysctl_print_dir and use it in get_subdir Eric W. Biederman
2012-01-27 4:52 ` [PATCH 24/29] sysctl: Replace root_list with links between sysctl_table_sets Eric W. Biederman
2012-01-30 0:01 ` Lucian Adrian Grijincu
2012-01-31 3:10 ` Eric W. Biederman
2012-01-30 17:51 ` Dave Jones
2012-01-31 2:11 ` Eric W. Biederman
2012-01-31 2:13 ` Joe Perches
2012-01-27 4:52 ` [PATCH 25/29] sysctl: Modify __register_sysctl_paths to take a set instead of a root and an nsproxy Eric W. Biederman
2012-01-27 4:52 ` [PATCH 26/29] sysctl: Move sysctl_check_dups into insert_header Eric W. Biederman
2012-01-27 4:52 ` [PATCH 27/29] sysctl: Make the header lists per directory Eric W. Biederman
2012-01-27 4:52 ` [PATCH 28/29] sysctl: Index sysctl directories with rbtrees Eric W. Biederman
2012-01-27 4:52 ` [PATCH 29/29] sysctl: Add register_sysctl for normal sysctl users Eric W. Biederman
2012-02-02 3:27 ` [Review][PATCH][0/4] sysctl bitty fixes Eric W. Biederman
2012-02-02 3:28 ` [PATCH 1/4] sysctl: An easier to read version of find_subdir Eric W. Biederman
2012-02-02 3:29 ` [PATCH 2/4] sysctl: Correct error return from get_subdir Eric W. Biederman
2012-02-02 3:29 ` [PATCH 3/4] sysctl: Comments to make the code clearer Eric W. Biederman
2012-02-02 16:28 ` Ben Hutchings
2012-02-02 3:30 ` [PATCH 4/4] sysctl: Don't call sysctl_follow_link unless we are a link Eric W. Biederman
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=m1pqe2jaxy.fsf@fess.ebiederm.org \
--to=ebiederm@xmission.com \
--cc=damien.millescamps@6wind.com \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=lucian.grijincu@gmail.com \
--cc=netdev@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).