From: Jan Kara <jack@suse.cz>
To: Alexander Lochmann <alexander.lochmann@tu-dortmund.de>
Cc: Horst Schirmeier <horst.schirmeier@tu-dortmund.de>,
Theodore Ts'o <tytso@mit.edu>, Jan Kara <jack@suse.com>,
linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] Updated locking documentation for transaction_t
Date: Thu, 11 Feb 2021 16:50:47 +0100 [thread overview]
Message-ID: <20210211155047.GS19070@quack2.suse.cz> (raw)
In-Reply-To: <20210211135424.42826-1-alexander.lochmann@tu-dortmund.de>
On Thu 11-02-21 14:54:23, Alexander Lochmann wrote:
> Some members of transaction_t are allowed to be read without
> any lock being held if accessed from the correct context.
> We used LockDoc's findings to determine those members.
> Each member of them is marked with a short comment:
> "no lock needed for jbd2 thread".
>
> Signed-off-by: Alexander Lochmann <alexander.lochmann@tu-dortmund.de>
> Signed-off-by: Horst Schirmeier <horst.schirmeier@tu-dortmund.de>
Thanks. You can add:
Reviewed-by: Jan Kara <jack@suse.cz>
Honza
> ---
> include/linux/jbd2.h | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
> index 99d3cd051ac3..1f19d19f6435 100644
> --- a/include/linux/jbd2.h
> +++ b/include/linux/jbd2.h
> @@ -594,18 +594,18 @@ struct transaction_s
> */
> unsigned long t_log_start;
>
> - /* Number of buffers on the t_buffers list [j_list_lock] */
> + /* Number of buffers on the t_buffers list [j_list_lock, no locks needed for jbd2 thread] */
> int t_nr_buffers;
>
> /*
> * Doubly-linked circular list of all buffers reserved but not yet
> - * modified by this transaction [j_list_lock]
> + * modified by this transaction [j_list_lock, no locks needed for jbd2 thread]
> */
> struct journal_head *t_reserved_list;
>
> /*
> * Doubly-linked circular list of all metadata buffers owned by this
> - * transaction [j_list_lock]
> + * transaction [j_list_lock, no locks needed for jbd2 thread]
> */
> struct journal_head *t_buffers;
>
> @@ -631,7 +631,7 @@ struct transaction_s
> /*
> * Doubly-linked circular list of metadata buffers being shadowed by log
> * IO. The IO buffers on the iobuf list and the shadow buffers on this
> - * list match each other one for one at all times. [j_list_lock]
> + * list match each other one for one at all times. [j_list_lock, no locks needed for jbd2 thread]
> */
> struct journal_head *t_shadow_list;
>
> --
> 2.20.1
>
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
next prev parent reply other threads:[~2021-02-11 17:00 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-11 13:54 [PATCH v2] Updated locking documentation for transaction_t Alexander Lochmann
2021-02-11 15:50 ` Jan Kara [this message]
-- strict thread matches above, loose matches on Subject: below --
2019-03-18 18:42 Alexander Lochmann
2019-03-19 8:33 ` Jan Kara
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