Simplify uprobe registration/unregistration interfaces by making offset
and ref_ctr_offset part of uprobe_consumer "interface". In practice, all
existing users already store these fields somewhere in uprobe_consumer's
containing structure, so this doesn't pose any problem. We just move
some fields around.

On the other hand, this simplifies uprobe_register() and
uprobe_unregister() API by having only struct uprobe_consumer as one
thing representing attachment/detachment entity. This makes batched
versions of uprobe_register() and uprobe_unregister() simpler.

This also makes uprobe_register_refctr() unnecessary, so remove it and
simplify consumers.

No functional changes intended.

Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
 include/linux/uprobes.h                       | 18 +++----
 kernel/events/uprobes.c                       | 19 ++-----
 kernel/trace/bpf_trace.c                      | 21 +++-----
 kernel/trace/trace_uprobe.c                   | 53 ++++++++-----------
 .../selftests/bpf/bpf_testmod/bpf_testmod.c   | 22 ++++----
 5 files changed, 55 insertions(+), 78 deletions(-)

diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h
index b503fafb7fb3..a75ba37ce3c8 100644
--- a/include/linux/uprobes.h
+++ b/include/linux/uprobes.h

@@ -42,6 +42,11 @@ struct uprobe_consumer {
 				enum uprobe_filter_ctx ctx,
 				struct mm_struct *mm);
 
+	/* associated file offset of this probe */
+	loff_t offset;
+	/* associated refctr file offset of this probe, or zero */
+	loff_t ref_ctr_offset;
+	/* for internal uprobe infra use, consumers shouldn't touch fields below */
 	struct uprobe_consumer *next;
 };
 

@@ -110,10 +115,9 @@ extern bool is_trap_insn(uprobe_opcode_t *insn);
 extern unsigned long uprobe_get_swbp_addr(struct pt_regs *regs);
 extern unsigned long uprobe_get_trap_addr(struct pt_regs *regs);
 extern int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr, uprobe_opcode_t);
-extern int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *uc);
-extern int uprobe_register_refctr(struct inode *inode, loff_t offset, loff_t ref_ctr_offset, struct uprobe_consumer *uc);
+extern int uprobe_register(struct inode *inode, struct uprobe_consumer *uc);
 extern int uprobe_apply(struct inode *inode, loff_t offset, struct uprobe_consumer *uc, bool);
-extern void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc);
+extern void uprobe_unregister(struct inode *inode, struct uprobe_consumer *uc);