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Subject[PATCH 11/14] uprobes: introduce vaddr_to_offset(vma, vaddr)
Add the new helper, vaddr_to_offset(vma, vaddr) which returns the
offset in vma->vm_file this vaddr is mapped at.

Change build_probe_list() and find_active_uprobe() to use the new
helper, the next patch adds another user.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar.vnet.ibm.com>
---
kernel/events/uprobes.c | 14 ++++++++------
1 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index c825404..5c87042 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -122,6 +122,11 @@ static loff_t vma_address(struct vm_area_struct *vma, loff_t offset)
return vaddr;
}

+static loff_t vaddr_to_offset(struct vm_area_struct *vma, unsigned long vaddr)
+{
+ return ((loff_t)vma->vm_pgoff << PAGE_SHIFT) + (vaddr - vma->vm_start);
+}
+
/**
* __replace_page - replace page in vma by new page.
* based on replace_page in mm/ksm.c
@@ -978,7 +983,7 @@ static void build_probe_list(struct inode *inode,
struct uprobe *u;

INIT_LIST_HEAD(head);
- min = ((loff_t)vma->vm_pgoff << PAGE_SHIFT) + start - vma->vm_start;
+ min = vaddr_to_offset(vma, start);
max = min + (end - start) - 1;

spin_lock_irqsave(&uprobes_treelock, flags);
@@ -1442,12 +1447,9 @@ static struct uprobe *find_active_uprobe(unsigned long bp_vaddr, int *is_swbp)
vma = find_vma(mm, bp_vaddr);
if (vma && vma->vm_start <= bp_vaddr) {
if (valid_vma(vma, false)) {
- struct inode *inode;
- loff_t offset;
+ struct inode *inode = vma->vm_file->f_mapping->host;
+ loff_t offset = vaddr_to_offset(vma, bp_vaddr);

- inode = vma->vm_file->f_mapping->host;
- offset = bp_vaddr - vma->vm_start;
- offset += (loff_t)vma->vm_pgoff << PAGE_SHIFT;
uprobe = find_uprobe(inode, offset);
}

--
1.5.5.1


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