[PATCHv6 perf/core 07/22] uprobes: Add do_ref_ctr argument to uprobe_write function

[Jiri Olsa]

Making update_ref_ctr call in uprobe_write conditional based
on do_ref_ctr argument. This way we can use uprobe_write for
instruction update without doing ref_ctr_offset update.

Reviewed-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
Acked-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
---
 include/linux/uprobes.h | 2 +-
 kernel/events/uprobes.c | 8 ++++----
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h
index 518b26756469..5080619560d4 100644
--- a/include/linux/uprobes.h
+++ b/include/linux/uprobes.h
@@ -200,7 +200,7 @@ extern unsigned long uprobe_get_trap_addr(struct pt_regs *regs);
 extern int uprobe_write_opcode(struct arch_uprobe *auprobe, struct vm_area_struct *vma, unsigned long vaddr, uprobe_opcode_t,
 			       bool is_register);
 extern int uprobe_write(struct arch_uprobe *auprobe, struct vm_area_struct *vma, const unsigned long opcode_vaddr,
-			uprobe_opcode_t *insn, int nbytes, uprobe_write_verify_t verify, bool is_register);
+			uprobe_opcode_t *insn, int nbytes, uprobe_write_verify_t verify, bool is_register, bool do_update_ref_ctr);
 extern struct uprobe *uprobe_register(struct inode *inode, loff_t offset, loff_t ref_ctr_offset, struct uprobe_consumer *uc);
 extern int uprobe_apply(struct uprobe *uprobe, struct uprobe_consumer *uc, bool);
 extern void uprobe_unregister_nosync(struct uprobe *uprobe, struct uprobe_consumer *uc);
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 1e5dc3b30707..6795b8d82b9c 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -492,12 +492,12 @@ int uprobe_write_opcode(struct arch_uprobe *auprobe, struct vm_area_struct *vma,
 		bool is_register)
 {
 	return uprobe_write(auprobe, vma, opcode_vaddr, &opcode, UPROBE_SWBP_INSN_SIZE,
-			    verify_opcode, is_register);
+			    verify_opcode, is_register, true /* do_update_ref_ctr */);
 }
 
 int uprobe_write(struct arch_uprobe *auprobe, struct vm_area_struct *vma,
 		 const unsigned long insn_vaddr, uprobe_opcode_t *insn, int nbytes,
-		 uprobe_write_verify_t verify, bool is_register)
+		 uprobe_write_verify_t verify, bool is_register, bool do_update_ref_ctr)
 {
 	const unsigned long vaddr = insn_vaddr & PAGE_MASK;
 	struct mm_struct *mm = vma->vm_mm;
@@ -538,7 +538,7 @@ int uprobe_write(struct arch_uprobe *auprobe, struct vm_area_struct *vma,
 	}
 
 	/* We are going to replace instruction, update ref_ctr. */
-	if (!ref_ctr_updated && uprobe->ref_ctr_offset) {
+	if (do_update_ref_ctr && !ref_ctr_updated && uprobe->ref_ctr_offset) {
 		ret = update_ref_ctr(uprobe, mm, is_register ? 1 : -1);
 		if (ret) {
 			folio_put(folio);
@@ -590,7 +590,7 @@ int uprobe_write(struct arch_uprobe *auprobe, struct vm_area_struct *vma,
 
 out:
 	/* Revert back reference counter if instruction update failed. */
-	if (ret < 0 && ref_ctr_updated)
+	if (do_update_ref_ctr && ret < 0 && ref_ctr_updated)
 		update_ref_ctr(uprobe, mm, is_register ? -1 : 1);
 
 	/* try collapse pmd for compound page */
-- 
2.50.1