[PATCH v2 4/5] uprobes: kill uprobe_register_refctr()

Oleg Nesterov
2024-07-29T13:45:40Z

It doesn't make any sense to have 2 versions of _register(). Note that
trace_uprobe_enable(), the only user of uprobe_register(), doesn't need
to check tu->ref_ctr_offset to decide which one should be used, it could
safely pass ref_ctr_offset == 0 to uprobe_register_refctr().

Add this argument to uprobe_register(), update the callers, and kill
uprobe_register_refctr().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
---
include/linux/uprobes.h | 9 ++-------
kernel/events/uprobes.c | 24 ++++++------------------
kernel/trace/bpf_trace.c | 8 ++++----
kernel/trace/trace_uprobe.c | 7 +------
4 files changed, 13 insertions(+), 35 deletions(-)

diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h
index b503fafb7fb3..440316fbf3c6 100644
--- a/include/linux/uprobes.h
+++ b/include/linux/uprobes.h
@@ -110,8 +110,7 @@ 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, loff_t offset, loff_t ref_ctr_offset, 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 int uprobe_mmap(struct vm_area_struct *vma);
@@ -152,11 +151,7 @@ static inline void uprobes_init(void)
#define uprobe_get_trap_addr(regs) instruction_pointer(regs)

static inline int
-uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *uc)
-{
- return -ENOSYS;
-}
-static inline int uprobe_register_refctr(struct inode *inode, loff_t offset, loff_t ref_ctr_offset, struct uprobe_consumer *uc)
+uprobe_register(struct inode *inode, loff_t offset, loff_t ref_ctr_offset, struct uprobe_consumer *uc)
{
return -ENOSYS;
}
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index dfe6306a63b1..b7f40bad8abc 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -1121,25 +1121,26 @@ void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consume
EXPORT_SYMBOL_GPL(uprobe_unregister);

/*
- * __uprobe_register - register a probe
+ * uprobe_register - register a probe
* @inode: the file in which the probe has to be placed.
* @offset: offset from the start of the file.
+ * @ref_ctr_offset: offset of SDT marker / reference counter
* @uc: information on howto handle the probe..
*
- * Apart from the access refcount, __uprobe_register() takes a creation
+ * Apart from the access refcount, uprobe_register() takes a creation
* refcount (thro alloc_uprobe) if and only if this @uprobe is getting
* inserted into the rbtree (i.e first consumer for a @inode:@offset
* tuple). Creation refcount stops uprobe_unregister from freeing the
* @uprobe even before the register operation is complete. Creation
* refcount is released when the last @uc for the @uprobe
- * unregisters. Caller of __uprobe_register() is required to keep @inode
+ * unregisters. Caller of uprobe_register() is required to keep @inode
* (and the containing mount) referenced.
*
* Return errno if it cannot successully install probes
* else return 0 (success)
*/
-static int __uprobe_register(struct inode *inode, loff_t offset,
- loff_t ref_ctr_offset, struct uprobe_consumer *uc)
+int uprobe_register(struct inode *inode, loff_t offset, loff_t ref_ctr_offset,
+ struct uprobe_consumer *uc)
{
struct uprobe *uprobe;
int ret;
@@ -1189,21 +1190,8 @@ static int __uprobe_register(struct inode *inode, loff_t offset,
goto retry;
return ret;
}
-
-int uprobe_register(struct inode *inode, loff_t offset,
- struct uprobe_consumer *uc)
-{
- return __uprobe_register(inode, offset, 0, uc);
-}
EXPORT_SYMBOL_GPL(uprobe_register);

-int uprobe_register_refctr(struct inode *inode, loff_t offset,
- loff_t ref_ctr_offset, struct uprobe_consumer *uc)
-{
- return __uprobe_register(inode, offset, ref_ctr_offset, uc);
-}
-EXPORT_SYMBOL_GPL(uprobe_register_refctr);
-
/*
* uprobe_apply - unregister an already registered probe.
* @inode: the file in which the probe has to be removed.
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index cd098846e251..afa909e17824 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -3480,10 +3480,10 @@ int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
&bpf_uprobe_multi_link_lops, prog);

for (i = 0; i < cnt; i++) {
- err = uprobe_register_refctr(d_real_inode(link->path.dentry),
- uprobes[i].offset,
- uprobes[i].ref_ctr_offset,
- &uprobes[i].consumer);
+ err = uprobe_register(d_real_inode(link->path.dentry),
+ uprobes[i].offset,
+ uprobes[i].ref_ctr_offset,
+ &uprobes[i].consumer);
if (err) {
bpf_uprobe_unregister(&path, uprobes, i);
goto error_free;
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index c98e3b3386ba..1f590f989c1e 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -1089,12 +1089,7 @@ static int trace_uprobe_enable(struct trace_uprobe *tu, filter_func_t filter)
tu->consumer.filter = filter;
tu->inode = d_real_inode(tu->path.dentry);

- if (tu->ref_ctr_offset)
- ret = uprobe_register_refctr(tu->inode, tu->offset,
- tu->ref_ctr_offset, &tu->consumer);
- else
- ret = uprobe_register(tu->inode, tu->offset, &tu->consumer);
-
+ ret = uprobe_register(tu->inode, tu->offset, tu->ref_ctr_offset, &tu->consumer);
if (ret)
tu->inode = NULL;

--
2.25.1.362.g51ebf55