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Commit 441f1eb7 authored by Oleg Nesterov's avatar Oleg Nesterov
Browse files

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: default avatarOleg Nesterov <oleg@redhat.com>
Acked-by: default avatarAnton Arapov <anton@redhat.com>
Acked-by: default avatarSrikar Dronamraju <srikar@linux.vnet.ibm.com>
parent d4d3ccc6

kernel/events/uprobes.c

+7 −12
Original line number Original line Diff line number Diff line
@@ -41,6 +41,11 @@ 
#define MAX_UPROBE_XOL_SLOTS		UINSNS_PER_PAGE

#define MAX_UPROBE_XOL_SLOTS		UINSNS_PER_PAGE





static struct rb_root uprobes_tree = RB_ROOT;

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 */

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;

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 */

/* Have a copy of original instruction */

#define UPROBE_COPY_INSN	0

#define UPROBE_COPY_INSN	0

/* Can skip singlestep */

/* Can skip singlestep */
@@ -460,8 +458,6 @@ static struct uprobe *alloc_uprobe(struct inode *inode, loff_t offset) 
		kfree(uprobe);

		kfree(uprobe);

		uprobe = cur_uprobe;

		uprobe = cur_uprobe;

		iput(inode);

		iput(inode);

	} else {

		atomic_inc(&uprobe_events);

	}

	}





	return uprobe;

	return uprobe;
@@ -685,7 +681,6 @@ static void delete_uprobe(struct uprobe *uprobe) 
	spin_unlock(&uprobes_treelock);

	spin_unlock(&uprobes_treelock);

	iput(uprobe->inode);

	iput(uprobe->inode);

	put_uprobe(uprobe);

	put_uprobe(uprobe);

	atomic_dec(&uprobe_events);

}

}





struct map_info {

struct map_info {
@@ -975,7 +970,7 @@ int uprobe_mmap(struct vm_area_struct *vma) 
	struct uprobe *uprobe, *u;

	struct uprobe *uprobe, *u;

	struct inode *inode;

	struct inode *inode;





	if (!atomic_read(&uprobe_events) || !valid_vma(vma, true))

	if (no_uprobe_events() || !valid_vma(vma, true))

		return 0;

		return 0;





	inode = vma->vm_file->f_mapping->host;

	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)

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;

		return;





	if (!atomic_read(&vma->vm_mm->mm_users)) /* called by mmput() ? */

	if (!atomic_read(&vma->vm_mm->mm_users)) /* called by mmput() ? */