Commit-ID: 441f1eb7db8babe2b6b4bc805f023739dbb70e33
Gitweb: http://git.kernel.org/tip/441f1eb7db8babe2b6b4bc805f023739dbb70e33
Author: Oleg Nesterov <oleg@xxxxxxxxxx>
AuthorDate: Sun, 25 Nov 2012 19:54:29 +0100
Committer: Oleg Nesterov <oleg@xxxxxxxxxx>
CommitDate: Fri, 8 Feb 2013 17:47:08 +0100
uprobes: Kill uprobe_events, use RB_EMPTY_ROOT() instead
uprobe_events counts the number of uprobes in uprobes_tree but
it is used as a boolean. We can use RB_EMPTY_ROOT() instead.
Probably no_uprobe_events() added by this patch can have more
callers, say, mmf_recalc_uprobes().
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Acked-by: Anton Arapov <anton@xxxxxxxxxx>
Acked-by: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx>
---
kernel/events/uprobes.c | 19 +++++++------------
1 file changed, 7 insertions(+), 12 deletions(-)
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 40ced98..5d38b40 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -41,6 +41,11 @@
#define MAX_UPROBE_XOL_SLOTS UINSNS_PER_PAGE
static struct rb_root uprobes_tree = RB_ROOT;
+/*
+ * allows us to skip the uprobe_mmap if there are no uprobe events active
+ * at this time. Probably a fine grained per inode count is better?
+ */
+#define no_uprobe_events() RB_EMPTY_ROOT(&uprobes_tree)
static DEFINE_SPINLOCK(uprobes_treelock); /* serialize rbtree access */
@@ -74,13 +79,6 @@ static struct mutex uprobes_mmap_mutex[UPROBES_HASH_SZ];
static struct percpu_rw_semaphore dup_mmap_sem;
-/*
- * uprobe_events allows us to skip the uprobe_mmap if there are no uprobe
- * events active at this time. Probably a fine grained per inode count is
- * better?
- */
-static atomic_t uprobe_events = ATOMIC_INIT(0);
-
/* Have a copy of original instruction */
#define UPROBE_COPY_INSN 0
/* Can skip singlestep */
@@ -460,8 +458,6 @@ static struct uprobe *alloc_uprobe(struct inode *inode, loff_t offset)
kfree(uprobe);
uprobe = cur_uprobe;
iput(inode);
- } else {
- atomic_inc(&uprobe_events);
}
return uprobe;
@@ -685,7 +681,6 @@ static void delete_uprobe(struct uprobe *uprobe)
spin_unlock(&uprobes_treelock);
iput(uprobe->inode);
put_uprobe(uprobe);
- atomic_dec(&uprobe_events);
}
struct map_info {
@@ -975,7 +970,7 @@ int uprobe_mmap(struct vm_area_struct *vma)
struct uprobe *uprobe, *u;
struct inode *inode;
- if (!atomic_read(&uprobe_events) || !valid_vma(vma, true))
+ if (no_uprobe_events() || !valid_vma(vma, true))
return 0;
inode = vma->vm_file->f_mapping->host;
@@ -1021,7 +1016,7 @@ vma_has_uprobes(struct vm_area_struct *vma, unsigned long start, unsigned long e
*/
void uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned long end)
{
- if (!atomic_read(&uprobe_events) || !valid_vma(vma, false))
+ if (no_uprobe_events() || !valid_vma(vma, false))
return;
if (!atomic_read(&vma->vm_mm->mm_users)) /* called by mmput() ? */
--
To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
|