diff options
author | Christoph Hellwig <hch@lst.de> | 2007-05-08 00:34:14 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-05-08 11:15:19 -0700 |
commit | 4c4308cb93450989846ac49faeb6dab943e7657e (patch) | |
tree | c06092cae6f95a243cdd758d07491cf5fa24a1dd /kernel | |
parent | 6f716acd5fa20ae6a35ab29ae37fa9189e839ed5 (diff) |
kprobes: kretprobes simplifications
- consolidate duplicate code in all arch_prepare_kretprobe instances
into common code
- replace various odd helpers that use hlist_for_each_entry to get
the first elemenet of a list with either a hlist_for_each_entry_save
or an opencoded access to the first element in the caller
- inline add_rp_inst into it's only remaining caller
- use kretprobe_inst_table_head instead of opencoding it
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Prasanna S Panchamukhi <prasanna@in.ibm.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/kprobes.c | 64 |
1 files changed, 21 insertions, 43 deletions
diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 22857003a65b..f58f171bd65f 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -358,46 +358,6 @@ void __kprobes kprobes_inc_nmissed_count(struct kprobe *p) } /* Called with kretprobe_lock held */ -struct kretprobe_instance __kprobes *get_free_rp_inst(struct kretprobe *rp) -{ - struct hlist_node *node; - struct kretprobe_instance *ri; - hlist_for_each_entry(ri, node, &rp->free_instances, uflist) - return ri; - return NULL; -} - -/* Called with kretprobe_lock held */ -static struct kretprobe_instance __kprobes *get_used_rp_inst(struct kretprobe - *rp) -{ - struct hlist_node *node; - struct kretprobe_instance *ri; - hlist_for_each_entry(ri, node, &rp->used_instances, uflist) - return ri; - return NULL; -} - -/* Called with kretprobe_lock held */ -void __kprobes add_rp_inst(struct kretprobe_instance *ri) -{ - /* - * Remove rp inst off the free list - - * Add it back when probed function returns - */ - hlist_del(&ri->uflist); - - /* Add rp inst onto table */ - INIT_HLIST_NODE(&ri->hlist); - hlist_add_head(&ri->hlist, - &kretprobe_inst_table[hash_ptr(ri->task, KPROBE_HASH_BITS)]); - - /* Also add this rp inst to the used list. */ - INIT_HLIST_NODE(&ri->uflist); - hlist_add_head(&ri->uflist, &ri->rp->used_instances); -} - -/* Called with kretprobe_lock held */ void __kprobes recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head) { @@ -450,7 +410,9 @@ void __kprobes kprobe_flush_task(struct task_struct *tk) static inline void free_rp_inst(struct kretprobe *rp) { struct kretprobe_instance *ri; - while ((ri = get_free_rp_inst(rp)) != NULL) { + struct hlist_node *pos, *next; + + hlist_for_each_entry_safe(ri, pos, next, &rp->free_instances, uflist) { hlist_del(&ri->uflist); kfree(ri); } @@ -732,7 +694,21 @@ static int __kprobes pre_handler_kretprobe(struct kprobe *p, /*TODO: consider to only swap the RA after the last pre_handler fired */ spin_lock_irqsave(&kretprobe_lock, flags); - arch_prepare_kretprobe(rp, regs); + if (!hlist_empty(&rp->free_instances)) { + struct kretprobe_instance *ri; + + ri = hlist_entry(rp->free_instances.first, + struct kretprobe_instance, uflist); + ri->rp = rp; + ri->task = current; + arch_prepare_kretprobe(ri, regs); + + /* XXX(hch): why is there no hlist_move_head? */ + hlist_del(&ri->uflist); + hlist_add_head(&ri->uflist, &ri->rp->used_instances); + hlist_add_head(&ri->hlist, kretprobe_inst_table_head(ri->task)); + } else + rp->nmissed++; spin_unlock_irqrestore(&kretprobe_lock, flags); return 0; } @@ -795,11 +771,13 @@ void __kprobes unregister_kretprobe(struct kretprobe *rp) { unsigned long flags; struct kretprobe_instance *ri; + struct hlist_node *pos, *next; unregister_kprobe(&rp->kp); + /* No race here */ spin_lock_irqsave(&kretprobe_lock, flags); - while ((ri = get_used_rp_inst(rp)) != NULL) { + hlist_for_each_entry_safe(ri, pos, next, &rp->used_instances, uflist) { ri->rp = NULL; hlist_del(&ri->uflist); } |