Patch "fanotify: Fold event size calculation to its own function" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    fanotify: Fold event size calculation to its own function

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     fanotify-fold-event-size-calculation-to-its-own-func.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit dcedb6eac6307e58cd68383eeb5a278722ecba71
Author: Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxx>
Date:   Mon Oct 25 16:27:20 2021 -0300

    fanotify: Fold event size calculation to its own function
    
    [ Upstream commit b9928e80dda84b349ba8de01780b9bef2fc36ffa ]
    
    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.
    
    Link: https://lore.kernel.org/r/20211025192746.66445-6-krisman@xxxxxxxxxxxxx
    Reviewed-by: Amir Goldstein <amir73il@xxxxxxxxx>
    Reviewed-by: Jan Kara <jack@xxxxxxx>
    Signed-off-by: Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxx>
    Signed-off-by: Jan Kara <jack@xxxxxxx>
    Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>

diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 0e2a0eb7cb9e0..20b743b05b997 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -126,17 +126,24 @@ static int fanotify_fid_info_len(int fh_len, int name_len)
 		       FANOTIFY_EVENT_ALIGN);
 }
 
-static int fanotify_event_info_len(unsigned int info_mode,
-				   struct fanotify_event *event)
+static size_t fanotify_event_len(unsigned int info_mode,
+				 struct fanotify_event *event)
 {
-	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 (!info_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 ((info_mode & FAN_REPORT_NAME) &&
 		   (event->mask & FAN_ONDIR)) {
 		/*
@@ -147,12 +154,12 @@ static int fanotify_event_info_len(unsigned int info_mode,
 	}
 
 	if (info_mode & FAN_REPORT_PIDFD)
-		info_len += FANOTIFY_PIDFD_INFO_HDR_LEN;
+		event_len += FANOTIFY_PIDFD_INFO_HDR_LEN;
 
 	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;
 }
 
 /*
@@ -181,7 +188,7 @@ 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 info_mode = FAN_GROUP_FLAG(group, FANOTIFY_INFO_MODES);
@@ -194,8 +201,7 @@ static struct fanotify_event *get_one_event(struct fsnotify_group *group,
 		goto out;
 
 	event = FANOTIFY_E(fsn_event);
-	if (info_mode)
-		event_size += fanotify_event_info_len(info_mode, event);
+	event_size = fanotify_event_len(info_mode, event);
 
 	if (event_size > count) {
 		event = ERR_PTR(-EINVAL);
@@ -537,8 +543,7 @@ 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(info_mode, event);
+	metadata.event_len = fanotify_event_len(info_mode, event);
 	metadata.metadata_len = FAN_EVENT_METADATA_LEN;
 	metadata.vers = FANOTIFY_METADATA_VERSION;
 	metadata.reserved = 0;