uprobes: Teach build_probe_list() to consider the range
Currently build_probe_list() builds the list of all uprobes attached to the given inode, and the caller should filter out those who don't fall into the [start,end) range, this is sub-optimal. This patch turns find_least_offset_node() into find_node_in_range() which returns the first node inside the [min,max] range, and changes build_probe_list() to use this node as a starting point for rb_prev() and rb_next() to find all other nodes the caller needs. The resulting list is no longer sorted but we do not care. This can speed up both build_probe_list() and the callers, but there is another reason to introduce find_node_in_range(). It can be used to figure out whether the given vma has uprobes or not, this will be needed soon. While at it, shift INIT_LIST_HEAD(tmp_list) into build_probe_list(). Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar.vnet.ibm.com> Cc: Anton Arapov <anton@redhat.com> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/20120729182240.GA20352@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
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@ -939,59 +939,66 @@ void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consume
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put_uprobe(uprobe);
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}
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/*
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* Of all the nodes that correspond to the given inode, return the node
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* with the least offset.
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*/
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static struct rb_node *find_least_offset_node(struct inode *inode)
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static struct rb_node *
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find_node_in_range(struct inode *inode, loff_t min, loff_t max)
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{
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struct uprobe u = { .inode = inode, .offset = 0};
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struct rb_node *n = uprobes_tree.rb_node;
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struct rb_node *close_node = NULL;
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struct uprobe *uprobe;
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int match;
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while (n) {
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uprobe = rb_entry(n, struct uprobe, rb_node);
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match = match_uprobe(&u, uprobe);
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struct uprobe *u = rb_entry(n, struct uprobe, rb_node);
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if (uprobe->inode == inode)
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close_node = n;
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if (!match)
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return close_node;
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if (match < 0)
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if (inode < u->inode) {
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n = n->rb_left;
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else
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} else if (inode > u->inode) {
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n = n->rb_right;
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} else {
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if (max < u->offset)
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n = n->rb_left;
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else if (min > u->offset)
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n = n->rb_right;
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else
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break;
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}
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}
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return close_node;
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return n;
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}
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/*
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* For a given inode, build a list of probes that need to be inserted.
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* For a given range in vma, build a list of probes that need to be inserted.
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*/
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static void build_probe_list(struct inode *inode, struct list_head *head)
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static void build_probe_list(struct inode *inode,
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struct vm_area_struct *vma,
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unsigned long start, unsigned long end,
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struct list_head *head)
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{
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struct uprobe *uprobe;
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loff_t min, max;
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unsigned long flags;
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struct rb_node *n;
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struct rb_node *n, *t;
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struct uprobe *u;
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INIT_LIST_HEAD(head);
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min = ((loff_t)vma->vm_pgoff << PAGE_SHIFT) + start - vma->vm_start;
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max = min + (end - start) - 1;
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spin_lock_irqsave(&uprobes_treelock, flags);
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n = find_least_offset_node(inode);
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for (; n; n = rb_next(n)) {
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uprobe = rb_entry(n, struct uprobe, rb_node);
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if (uprobe->inode != inode)
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break;
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list_add(&uprobe->pending_list, head);
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atomic_inc(&uprobe->ref);
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n = find_node_in_range(inode, min, max);
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if (n) {
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for (t = n; t; t = rb_prev(t)) {
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u = rb_entry(t, struct uprobe, rb_node);
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if (u->inode != inode || u->offset < min)
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break;
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list_add(&u->pending_list, head);
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atomic_inc(&u->ref);
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}
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for (t = n; (t = rb_next(t)); ) {
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u = rb_entry(t, struct uprobe, rb_node);
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if (u->inode != inode || u->offset > max)
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break;
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list_add(&u->pending_list, head);
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atomic_inc(&u->ref);
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}
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}
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spin_unlock_irqrestore(&uprobes_treelock, flags);
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}
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@ -1021,9 +1028,8 @@ int uprobe_mmap(struct vm_area_struct *vma)
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if (!inode)
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return 0;
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INIT_LIST_HEAD(&tmp_list);
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mutex_lock(uprobes_mmap_hash(inode));
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build_probe_list(inode, &tmp_list);
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build_probe_list(inode, vma, vma->vm_start, vma->vm_end, &tmp_list);
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ret = 0;
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count = 0;
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@ -1032,11 +1038,6 @@ int uprobe_mmap(struct vm_area_struct *vma)
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if (!ret) {
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loff_t vaddr = vma_address(vma, uprobe->offset);
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if (vaddr < vma->vm_start || vaddr >= vma->vm_end) {
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put_uprobe(uprobe);
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continue;
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}
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ret = install_breakpoint(uprobe, vma->vm_mm, vma, vaddr);
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/*
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* We can race against uprobe_register(), see the
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@ -1092,21 +1093,17 @@ void uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned lon
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if (!inode)
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return;
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INIT_LIST_HEAD(&tmp_list);
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mutex_lock(uprobes_mmap_hash(inode));
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build_probe_list(inode, &tmp_list);
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build_probe_list(inode, vma, start, end, &tmp_list);
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list_for_each_entry_safe(uprobe, u, &tmp_list, pending_list) {
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loff_t vaddr = vma_address(vma, uprobe->offset);
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if (vaddr >= start && vaddr < end) {
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/*
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* An unregister could have removed the probe before
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* unmap. So check before we decrement the count.
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*/
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if (is_swbp_at_addr(vma->vm_mm, vaddr) == 1)
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atomic_dec(&vma->vm_mm->uprobes_state.count);
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}
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/*
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* An unregister could have removed the probe before
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* unmap. So check before we decrement the count.
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*/
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if (is_swbp_at_addr(vma->vm_mm, vaddr) == 1)
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atomic_dec(&vma->vm_mm->uprobes_state.count);
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put_uprobe(uprobe);
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}
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mutex_unlock(uprobes_mmap_hash(inode));
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