[5/7] uprobes: move the initialization of utask->xol_vaddr from pre_ssout() to xol_get_insn_slot()

Commit Message

Oleg Nesterov Sept. 29, 2024, 2:42 p.m. UTC

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 <[e-mail]>
---
 kernel/events/uprobes.c | 22 ++++++++--------------
 1 file changed, 8 insertions(+), 14 deletions(-)

Patch

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index bfe106ecad38..a7223be5ac2e 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -1649,21 +1649,19 @@  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;
 }
 
 /*
@@ -1951,21 +1949,17 @@  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);