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uprobes: Kill uprobe_events, use RB_EMPTY_ROOT() instead

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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@redhat.com>
Acked-by: Anton Arapov <anton@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
This commit is contained in:
Oleg Nesterov 2012-11-25 19:54:29 +01:00
parent d4d3ccc6d1
commit 441f1eb7db
1 changed files with 7 additions and 12 deletions
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19
kernel/events/uprobes.c
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@ -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() ? */