From cdac75e6f2fec9abc21d0abb4e5d80720eeebb10 Mon Sep 17 00:00:00 2001 From: Davide Libenzi Date: Tue, 29 Apr 2008 00:58:34 -0700 Subject: [PATCH] epoll: avoid kmemcheck warning Epoll calls rb_set_parent(n, n) to initialize the rb-tree node, but rb_set_parent() accesses node's pointer in its code. This creates a warning in kmemcheck (reported by Vegard Nossum) about an uninitialized memory access. The warning is harmless since the following rb-tree node insert is going to overwrite the node data. In any case I think it's better to not have that happening at all, and fix it by simplifying the code to get rid of a few lines that became superfluous after the previous epoll changes. Signed-off-by: Davide Libenzi Cc: Vegard Nossum Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/eventpoll.c | 27 +++------------------------ 1 file changed, 3 insertions(+), 24 deletions(-) diff --git a/fs/eventpoll.c b/fs/eventpoll.c index a415f42d32c..0d237182d72 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -257,25 +257,6 @@ static inline int ep_cmp_ffd(struct epoll_filefd *p1, (p1->file < p2->file ? -1 : p1->fd - p2->fd)); } -/* Special initialization for the RB tree node to detect linkage */ -static inline void ep_rb_initnode(struct rb_node *n) -{ - rb_set_parent(n, n); -} - -/* Removes a node from the RB tree and marks it for a fast is-linked check */ -static inline void ep_rb_erase(struct rb_node *n, struct rb_root *r) -{ - rb_erase(n, r); - rb_set_parent(n, n); -} - -/* Fast check to verify that the item is linked to the main RB tree */ -static inline int ep_rb_linked(struct rb_node *n) -{ - return rb_parent(n) != n; -} - /* Tells us if the item is currently linked */ static inline int ep_is_linked(struct list_head *p) { @@ -283,13 +264,13 @@ static inline int ep_is_linked(struct list_head *p) } /* Get the "struct epitem" from a wait queue pointer */ -static inline struct epitem * ep_item_from_wait(wait_queue_t *p) +static inline struct epitem *ep_item_from_wait(wait_queue_t *p) { return container_of(p, struct eppoll_entry, wait)->base; } /* Get the "struct epitem" from an epoll queue wrapper */ -static inline struct epitem * ep_item_from_epqueue(poll_table *p) +static inline struct epitem *ep_item_from_epqueue(poll_table *p) { return container_of(p, struct ep_pqueue, pt)->epi; } @@ -411,8 +392,7 @@ static int ep_remove(struct eventpoll *ep, struct epitem *epi) list_del_init(&epi->fllink); spin_unlock(&file->f_ep_lock); - if (ep_rb_linked(&epi->rbn)) - ep_rb_erase(&epi->rbn, &ep->rbr); + rb_erase(&epi->rbn, &ep->rbr); spin_lock_irqsave(&ep->lock, flags); if (ep_is_linked(&epi->rdllink)) @@ -728,7 +708,6 @@ static int ep_insert(struct eventpoll *ep, struct epoll_event *event, goto error_return; /* Item initialization follow here ... */ - ep_rb_initnode(&epi->rbn); INIT_LIST_HEAD(&epi->rdllink); INIT_LIST_HEAD(&epi->fllink); INIT_LIST_HEAD(&epi->pwqlist);