uprobes: move the initialization of utask->xol_vaddr from pre_ssout() to xol_get_insn...

This simplifies the code and makes xol_get_insn_slot() symmetric with
xol_free_insn_slot() which clears utask->xol_vaddr.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20240929144248.GA9483@redhat.com

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 616b5ff3fd85f70e0778c5364c5f5e954b4c3894..dfaca306443d6d68bf58874de5d5b009f9578b98 100644 (file)
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -1646,21 +1646,19 @@ static unsigned long xol_take_insn_slot(struct xol_area *area)
 
 /*
  * xol_get_insn_slot - allocate a slot for xol.
- * Returns the allocated slot address or 0.
  */
-static unsigned long xol_get_insn_slot(struct uprobe *uprobe)
+static bool xol_get_insn_slot(struct uprobe *uprobe)
 {
-       struct xol_area *area;
-       unsigned long xol_vaddr;
+       struct uprobe_task *utask = current->utask;
+       struct xol_area *area = get_xol_area();
 
-       area = get_xol_area();
        if (!area)
-               return 0;
+               return false;
 
-       xol_vaddr = xol_take_insn_slot(area);
-       arch_uprobe_copy_ixol(area->page, xol_vaddr,
+       utask->xol_vaddr = xol_take_insn_slot(area);
+       arch_uprobe_copy_ixol(area->page, utask->xol_vaddr,
                              &uprobe->arch.ixol, sizeof(uprobe->arch.ixol));
-       return xol_vaddr;
+       return true;
 }
 
 /*
@@ -1948,21 +1946,17 @@ static int
 pre_ssout(struct uprobe *uprobe, struct pt_regs *regs, unsigned long bp_vaddr)
 {
        struct uprobe_task *utask = current->utask;
-       unsigned long xol_vaddr;
        int err;
 
        if (!try_get_uprobe(uprobe))
                return -EINVAL;
 
-       xol_vaddr = xol_get_insn_slot(uprobe);
-       if (!xol_vaddr) {
+       if (!xol_get_insn_slot(uprobe)) {
                err = -ENOMEM;
                goto err_out;
        }
 
-       utask->xol_vaddr = xol_vaddr;
        utask->vaddr = bp_vaddr;
-
        err = arch_uprobe_pre_xol(&uprobe->arch, regs);
        if (unlikely(err)) {
                xol_free_insn_slot(current);