uprobes: Do not use -EEXIST in install_breakpoint() paths

-EEXIST from install_breakpoint() no longer makes sense, all
callers should simply treat it as "success". Change the code
to return zero and simplify register_for_each_vma().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>

1 files changed, 5 insertions, 11 deletions

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 298fbbdf57e..3e2996b809b 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -332,7 +332,7 @@ int __weak set_swbp(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned
          */
         result = is_swbp_at_addr(mm, vaddr);
         if (result == 1)
-                return -EEXIST;
+                return 0;
 
         if (result)
                 return result;
@@ -657,7 +657,7 @@ install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm,
          * Hence behave as if probe already existed.
          */
         if (!uprobe->consumers)
-                return -EEXIST;
+                return 0;
 
         if (!(uprobe->flags & UPROBE_COPY_INSN)) {
                 ret = copy_insn(uprobe, vma->vm_file);
@@ -817,17 +817,11 @@ static int register_for_each_vma(struct uprobe *uprobe, bool is_register)
                     vaddr_to_offset(vma, info->vaddr) != uprobe->offset)
                         goto unlock;
 
-                if (is_register) {
+                if (is_register)
                         err = install_breakpoint(uprobe, mm, vma, info->vaddr);
-                        /*
-                         * We can race against uprobe_mmap(), see the
-                         * comment near uprobe_hash().
-                         */
-                        if (err == -EEXIST)
-                                err = 0;
-                } else {
+                else
                         remove_breakpoint(uprobe, mm, info->vaddr);
-                }
+
  unlock:
                 up_write(&mm->mmap_sem);
  free: