5.10-stable review patch. If anyone has any objections, please let me know.
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From: Amir Goldstein amir73il@gmail.com
[ Upstream commit 8988f11abb820bacfcc53d498370bfb30f792ec4 ]
objectid is only used by fanotify backend and it is just an optimization for event merge before comparing all fields in event.
Move the objectid member from common struct fsnotify_event into struct fanotify_event and reduce it to 29-bit hash to cram it together with the 3-bit event type.
Events of different types are never merged, so the combination of event type and hash form a 32-bit key for fast compare of events.
This reduces the size of events by one pointer and paves the way for adding hashed queue support for fanotify.
Link: https://lore.kernel.org/r/20210304104826.3993892-3-amir73il@gmail.com Signed-off-by: Amir Goldstein amir73il@gmail.com Signed-off-by: Jan Kara jack@suse.cz Signed-off-by: Chuck Lever chuck.lever@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/notify/fanotify/fanotify.c | 25 ++++++++++++------------- fs/notify/fanotify/fanotify.h | 16 +++++++++++++--- fs/notify/inotify/inotify_fsnotify.c | 2 +- fs/notify/inotify/inotify_user.c | 2 +- include/linux/fsnotify_backend.h | 5 +---- 5 files changed, 28 insertions(+), 22 deletions(-)
diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c index 1192c99536200..8a2bb6954e02c 100644 --- a/fs/notify/fanotify/fanotify.c +++ b/fs/notify/fanotify/fanotify.c @@ -88,16 +88,12 @@ static bool fanotify_name_event_equal(struct fanotify_name_event *fne1, return fanotify_info_equal(info1, info2); }
-static bool fanotify_should_merge(struct fsnotify_event *old_fsn, - struct fsnotify_event *new_fsn) +static bool fanotify_should_merge(struct fanotify_event *old, + struct fanotify_event *new) { - struct fanotify_event *old, *new; + pr_debug("%s: old=%p new=%p\n", __func__, old, new);
- pr_debug("%s: old=%p new=%p\n", __func__, old_fsn, new_fsn); - old = FANOTIFY_E(old_fsn); - new = FANOTIFY_E(new_fsn); - - if (old_fsn->objectid != new_fsn->objectid || + if (old->hash != new->hash || old->type != new->type || old->pid != new->pid) return false;
@@ -133,10 +129,9 @@ static bool fanotify_should_merge(struct fsnotify_event *old_fsn, static int fanotify_merge(struct list_head *list, struct fsnotify_event *event) { struct fsnotify_event *test_event; - struct fanotify_event *new; + struct fanotify_event *old, *new = FANOTIFY_E(event);
pr_debug("%s: list=%p event=%p\n", __func__, list, event); - new = FANOTIFY_E(event);
/* * Don't merge a permission event with any other event so that we know @@ -147,8 +142,9 @@ static int fanotify_merge(struct list_head *list, struct fsnotify_event *event) return 0;
list_for_each_entry_reverse(test_event, list, list) { - if (fanotify_should_merge(test_event, event)) { - FANOTIFY_E(test_event)->mask |= new->mask; + old = FANOTIFY_E(test_event); + if (fanotify_should_merge(old, new)) { + old->mask |= new->mask; return 1; } } @@ -533,6 +529,7 @@ static struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group, struct mem_cgroup *old_memcg; struct inode *child = NULL; bool name_event = false; + unsigned int hash = 0;
if ((fid_mode & FAN_REPORT_DIR_FID) && dirid) { /* @@ -600,8 +597,10 @@ static struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group, * Use the victim inode instead of the watching inode as the id for * event queue, so event reported on parent is merged with event * reported on child when both directory and child watches exist. + * Hash object id for queue merge. */ - fanotify_init_event(event, (unsigned long)id, mask); + hash = hash_ptr(id, FANOTIFY_EVENT_HASH_BITS); + fanotify_init_event(event, hash, mask); if (FAN_GROUP_FLAG(group, FAN_REPORT_TID)) event->pid = get_pid(task_pid(current)); else diff --git a/fs/notify/fanotify/fanotify.h b/fs/notify/fanotify/fanotify.h index 896c819a17863..d531f0cfa46f2 100644 --- a/fs/notify/fanotify/fanotify.h +++ b/fs/notify/fanotify/fanotify.h @@ -135,19 +135,29 @@ enum fanotify_event_type { FANOTIFY_EVENT_TYPE_PATH, FANOTIFY_EVENT_TYPE_PATH_PERM, FANOTIFY_EVENT_TYPE_OVERFLOW, /* struct fanotify_event */ + __FANOTIFY_EVENT_TYPE_NUM };
+#define FANOTIFY_EVENT_TYPE_BITS \ + (ilog2(__FANOTIFY_EVENT_TYPE_NUM - 1) + 1) +#define FANOTIFY_EVENT_HASH_BITS \ + (32 - FANOTIFY_EVENT_TYPE_BITS) + struct fanotify_event { struct fsnotify_event fse; u32 mask; - enum fanotify_event_type type; + struct { + unsigned int type : FANOTIFY_EVENT_TYPE_BITS; + unsigned int hash : FANOTIFY_EVENT_HASH_BITS; + }; struct pid *pid; };
static inline void fanotify_init_event(struct fanotify_event *event, - unsigned long id, u32 mask) + unsigned int hash, u32 mask) { - fsnotify_init_event(&event->fse, id); + fsnotify_init_event(&event->fse); + event->hash = hash; event->mask = mask; event->pid = NULL; } diff --git a/fs/notify/inotify/inotify_fsnotify.c b/fs/notify/inotify/inotify_fsnotify.c index 66991c7fef9e2..e2b124c0081dc 100644 --- a/fs/notify/inotify/inotify_fsnotify.c +++ b/fs/notify/inotify/inotify_fsnotify.c @@ -114,7 +114,7 @@ int inotify_handle_inode_event(struct fsnotify_mark *inode_mark, u32 mask, mask &= ~IN_ISDIR;
fsn_event = &event->fse; - fsnotify_init_event(fsn_event, 0); + fsnotify_init_event(fsn_event); event->mask = mask; event->wd = wd; event->sync_cookie = cookie; diff --git a/fs/notify/inotify/inotify_user.c b/fs/notify/inotify/inotify_user.c index c2018983832e5..62cd91bc00b83 100644 --- a/fs/notify/inotify/inotify_user.c +++ b/fs/notify/inotify/inotify_user.c @@ -641,7 +641,7 @@ static struct fsnotify_group *inotify_new_group(unsigned int max_events) return ERR_PTR(-ENOMEM); } group->overflow_event = &oevent->fse; - fsnotify_init_event(group->overflow_event, 0); + fsnotify_init_event(group->overflow_event); oevent->mask = FS_Q_OVERFLOW; oevent->wd = -1; oevent->sync_cookie = 0; diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h index 7eb979bfc1413..fc98f9f88d126 100644 --- a/include/linux/fsnotify_backend.h +++ b/include/linux/fsnotify_backend.h @@ -167,7 +167,6 @@ struct fsnotify_ops { */ struct fsnotify_event { struct list_head list; - unsigned long objectid; /* identifier for queue merges */ };
/* @@ -582,11 +581,9 @@ extern void fsnotify_put_mark(struct fsnotify_mark *mark); extern void fsnotify_finish_user_wait(struct fsnotify_iter_info *iter_info); extern bool fsnotify_prepare_user_wait(struct fsnotify_iter_info *iter_info);
-static inline void fsnotify_init_event(struct fsnotify_event *event, - unsigned long objectid) +static inline void fsnotify_init_event(struct fsnotify_event *event) { INIT_LIST_HEAD(&event->list); - event->objectid = objectid; }
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