linux-ext4 - Re: [PATCH v3 02/15] fanotify: Fold event size calculation to its own function

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Date:   Wed, 7 Jul 2021 21:22:47 +0200
From:   Jan Kara <jack@...e.cz>
To:     Gabriel Krisman Bertazi <krisman@...labora.com>
Cc:     amir73il@...il.com, djwong@...nel.org, tytso@....edu,
        david@...morbit.com, jack@...e.com, dhowells@...hat.com,
        khazhy@...gle.com, linux-fsdevel@...r.kernel.org,
        linux-ext4@...r.kernel.org, kernel@...labora.com
Subject: Re: [PATCH v3 02/15] fanotify: Fold event size calculation to its
 own function

On Tue 29-06-21 15:10:22, Gabriel Krisman Bertazi wrote:
> Every time this function is invoked, it is immediately added to
> FAN_EVENT_METADATA_LEN, since there is no need to just calculate the
> length of info records. This minor clean up folds the rest of the
> calculation into the function, which now operates in terms of events,
> returning the size of the entire event, including metadata.
> 
> Reviewed-by: Amir Goldstein <amir73il@...il.com>
> Signed-off-by: Gabriel Krisman Bertazi <krisman@...labora.com>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <jack@...e.cz>

								Honza

> 
> ---
> Changes since v1:
>   - rebased on top of hashing patches
> ---
>  fs/notify/fanotify/fanotify_user.c | 33 +++++++++++++++++-------------
>  1 file changed, 19 insertions(+), 14 deletions(-)
> 
> diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
> index 64864fb40b40..68a53d3534f8 100644
> --- a/fs/notify/fanotify/fanotify_user.c
> +++ b/fs/notify/fanotify/fanotify_user.c
> @@ -117,17 +117,24 @@ static int fanotify_fid_info_len(int fh_len, int name_len)
>  	return roundup(FANOTIFY_INFO_HDR_LEN + info_len, FANOTIFY_EVENT_ALIGN);
>  }
>  
> -static int fanotify_event_info_len(unsigned int fid_mode,
> -				   struct fanotify_event *event)
> +static size_t fanotify_event_len(struct fanotify_event *event,
> +				 unsigned int fid_mode)
>  {
> -	struct fanotify_info *info = fanotify_event_info(event);
> -	int dir_fh_len = fanotify_event_dir_fh_len(event);
> -	int fh_len = fanotify_event_object_fh_len(event);
> -	int info_len = 0;
> +	size_t event_len = FAN_EVENT_METADATA_LEN;
> +	struct fanotify_info *info;
> +	int dir_fh_len;
> +	int fh_len;
>  	int dot_len = 0;
>  
> +	if (!fid_mode)
> +		return event_len;
> +
> +	info = fanotify_event_info(event);
> +	dir_fh_len = fanotify_event_dir_fh_len(event);
> +	fh_len = fanotify_event_object_fh_len(event);
> +
>  	if (dir_fh_len) {
> -		info_len += fanotify_fid_info_len(dir_fh_len, info->name_len);
> +		event_len += fanotify_fid_info_len(dir_fh_len, info->name_len);
>  	} else if ((fid_mode & FAN_REPORT_NAME) && (event->mask & FAN_ONDIR)) {
>  		/*
>  		 * With group flag FAN_REPORT_NAME, if name was not recorded in
> @@ -137,9 +144,9 @@ static int fanotify_event_info_len(unsigned int fid_mode,
>  	}
>  
>  	if (fh_len)
> -		info_len += fanotify_fid_info_len(fh_len, dot_len);
> +		event_len += fanotify_fid_info_len(fh_len, dot_len);
>  
> -	return info_len;
> +	return event_len;
>  }
>  
>  /*
> @@ -168,7 +175,7 @@ static void fanotify_unhash_event(struct fsnotify_group *group,
>  static struct fanotify_event *get_one_event(struct fsnotify_group *group,
>  					    size_t count)
>  {
> -	size_t event_size = FAN_EVENT_METADATA_LEN;
> +	size_t event_size;
>  	struct fanotify_event *event = NULL;
>  	struct fsnotify_event *fsn_event;
>  	unsigned int fid_mode = FAN_GROUP_FLAG(group, FANOTIFY_FID_BITS);
> @@ -181,8 +188,7 @@ static struct fanotify_event *get_one_event(struct fsnotify_group *group,
>  		goto out;
>  
>  	event = FANOTIFY_E(fsn_event);
> -	if (fid_mode)
> -		event_size += fanotify_event_info_len(fid_mode, event);
> +	event_size = fanotify_event_len(event, fid_mode);
>  
>  	if (event_size > count) {
>  		event = ERR_PTR(-EINVAL);
> @@ -412,8 +418,7 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group,
>  
>  	pr_debug("%s: group=%p event=%p\n", __func__, group, event);
>  
> -	metadata.event_len = FAN_EVENT_METADATA_LEN +
> -				fanotify_event_info_len(fid_mode, event);
> +	metadata.event_len = fanotify_event_len(event, fid_mode);
>  	metadata.metadata_len = FAN_EVENT_METADATA_LEN;
>  	metadata.vers = FANOTIFY_METADATA_VERSION;
>  	metadata.reserved = 0;
> -- 
> 2.32.0
> 
-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR