[PATCH v2 05/12] uprobes: move offset and ref_ctr_offset into uprobe_consumer

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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@xxxxxxxxxx>
Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
---
 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);
 extern int uprobe_mmap(struct vm_area_struct *vma);
 extern void uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned long end);
 extern void uprobe_start_dup_mmap(void);
@@ -152,11 +156,7 @@ 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, struct uprobe_consumer *uc)
 {
 	return -ENOSYS;
 }
@@ -166,7 +166,7 @@ uprobe_apply(struct inode *inode, loff_t offset, struct uprobe_consumer *uc, boo
 	return -ENOSYS;
 }
 static inline void
-uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc)
+uprobe_unregister(struct inode *inode, struct uprobe_consumer *uc)
 {
 }
 static inline int uprobe_mmap(struct vm_area_struct *vma)
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 560cf1ca512a..8759c6d0683e 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -1224,14 +1224,13 @@ __uprobe_unregister(struct uprobe *uprobe, struct uprobe_consumer *uc)
 /*
  * uprobe_unregister - unregister an already registered probe.
  * @inode: the file in which the probe has to be removed.
- * @offset: offset from the start of the file.
- * @uc: identify which probe if multiple probes are colocated.
+ * @uc: identify which probe consumer to unregister.
  */
-void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc)
+void uprobe_unregister(struct inode *inode, struct uprobe_consumer *uc)
 {
 	struct uprobe *uprobe;
 
-	uprobe = find_uprobe(inode, offset);
+	uprobe = find_uprobe(inode, uc->offset);
 	if (WARN_ON(!uprobe))
 		return;
 
@@ -1304,20 +1303,12 @@ static int __uprobe_register(struct inode *inode, loff_t offset,
 	return ret;
 }
 
-int uprobe_register(struct inode *inode, loff_t offset,
-		    struct uprobe_consumer *uc)
+int uprobe_register(struct inode *inode, struct uprobe_consumer *uc)
 {
-	return __uprobe_register(inode, offset, 0, uc);
+	return __uprobe_register(inode, uc->offset, uc->ref_ctr_offset, 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 d1daeab1bbc1..ba62baec3152 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -3154,8 +3154,6 @@ struct bpf_uprobe_multi_link;
 
 struct bpf_uprobe {
 	struct bpf_uprobe_multi_link *link;
-	loff_t offset;
-	unsigned long ref_ctr_offset;
 	u64 cookie;
 	struct uprobe_consumer consumer;
 };
@@ -3181,8 +3179,7 @@ static void bpf_uprobe_unregister(struct path *path, struct bpf_uprobe *uprobes,
 	u32 i;
 
 	for (i = 0; i < cnt; i++) {
-		uprobe_unregister(d_real_inode(path->dentry), uprobes[i].offset,
-				  &uprobes[i].consumer);
+		uprobe_unregister(d_real_inode(path->dentry), &uprobes[i].consumer);
 	}
 }
 
@@ -3262,10 +3259,10 @@ static int bpf_uprobe_multi_link_fill_link_info(const struct bpf_link *link,
 
 	for (i = 0; i < ucount; i++) {
 		if (uoffsets &&
-		    put_user(umulti_link->uprobes[i].offset, uoffsets + i))
+		    put_user(umulti_link->uprobes[i].consumer.offset, uoffsets + i))
 			return -EFAULT;
 		if (uref_ctr_offsets &&
-		    put_user(umulti_link->uprobes[i].ref_ctr_offset, uref_ctr_offsets + i))
+		    put_user(umulti_link->uprobes[i].consumer.ref_ctr_offset, uref_ctr_offsets + i))
 			return -EFAULT;
 		if (ucookies &&
 		    put_user(umulti_link->uprobes[i].cookie, ucookies + i))
@@ -3439,15 +3436,16 @@ int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
 		goto error_free;
 
 	for (i = 0; i < cnt; i++) {
-		if (__get_user(uprobes[i].offset, uoffsets + i)) {
+		if (__get_user(uprobes[i].consumer.offset, uoffsets + i)) {
 			err = -EFAULT;
 			goto error_free;
 		}
-		if (uprobes[i].offset < 0) {
+		if (uprobes[i].consumer.offset < 0) {
 			err = -EINVAL;
 			goto error_free;
 		}
-		if (uref_ctr_offsets && __get_user(uprobes[i].ref_ctr_offset, uref_ctr_offsets + i)) {
+		if (uref_ctr_offsets &&
+		    __get_user(uprobes[i].consumer.ref_ctr_offset, uref_ctr_offsets + i)) {
 			err = -EFAULT;
 			goto error_free;
 		}
@@ -3477,10 +3475,7 @@ 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].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..d786f99114be 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -60,8 +60,6 @@ struct trace_uprobe {
 	struct path			path;
 	struct inode			*inode;
 	char				*filename;
-	unsigned long			offset;
-	unsigned long			ref_ctr_offset;
 	unsigned long			nhit;
 	struct trace_probe		tp;
 };
@@ -205,7 +203,7 @@ static unsigned long translate_user_vaddr(unsigned long file_offset)
 
 	udd = (void *) current->utask->vaddr;
 
-	base_addr = udd->bp_addr - udd->tu->offset;
+	base_addr = udd->bp_addr - udd->tu->consumer.offset;
 	return base_addr + file_offset;
 }
 
@@ -286,13 +284,13 @@ static bool trace_uprobe_match_command_head(struct trace_uprobe *tu,
 	if (strncmp(tu->filename, argv[0], len) || argv[0][len] != ':')
 		return false;
 
-	if (tu->ref_ctr_offset == 0)
-		snprintf(buf, sizeof(buf), "0x%0*lx",
-				(int)(sizeof(void *) * 2), tu->offset);
+	if (tu->consumer.ref_ctr_offset == 0)
+		snprintf(buf, sizeof(buf), "0x%0*llx",
+				(int)(sizeof(void *) * 2), tu->consumer.offset);
 	else
-		snprintf(buf, sizeof(buf), "0x%0*lx(0x%lx)",
-				(int)(sizeof(void *) * 2), tu->offset,
-				tu->ref_ctr_offset);
+		snprintf(buf, sizeof(buf), "0x%0*llx(0x%llx)",
+				(int)(sizeof(void *) * 2), tu->consumer.offset,
+				tu->consumer.ref_ctr_offset);
 	if (strcmp(buf, &argv[0][len + 1]))
 		return false;
 
@@ -410,7 +408,7 @@ static bool trace_uprobe_has_same_uprobe(struct trace_uprobe *orig,
 
 	list_for_each_entry(orig, &tpe->probes, tp.list) {
 		if (comp_inode != d_real_inode(orig->path.dentry) ||
-		    comp->offset != orig->offset)
+		    comp->consumer.offset != orig->consumer.offset)
 			continue;
 
 		/*
@@ -472,8 +470,8 @@ static int validate_ref_ctr_offset(struct trace_uprobe *new)
 
 	for_each_trace_uprobe(tmp, pos) {
 		if (new_inode == d_real_inode(tmp->path.dentry) &&
-		    new->offset == tmp->offset &&
-		    new->ref_ctr_offset != tmp->ref_ctr_offset) {
+		    new->consumer.offset == tmp->consumer.offset &&
+		    new->consumer.ref_ctr_offset != tmp->consumer.ref_ctr_offset) {
 			pr_warn("Reference counter offset mismatch.");
 			return -EINVAL;
 		}
@@ -675,8 +673,8 @@ static int __trace_uprobe_create(int argc, const char **argv)
 		WARN_ON_ONCE(ret != -ENOMEM);
 		goto fail_address_parse;
 	}
-	tu->offset = offset;
-	tu->ref_ctr_offset = ref_ctr_offset;
+	tu->consumer.offset = offset;
+	tu->consumer.ref_ctr_offset = ref_ctr_offset;
 	tu->path = path;
 	tu->filename = filename;
 
@@ -746,12 +744,12 @@ static int trace_uprobe_show(struct seq_file *m, struct dyn_event *ev)
 	char c = is_ret_probe(tu) ? 'r' : 'p';
 	int i;
 
-	seq_printf(m, "%c:%s/%s %s:0x%0*lx", c, trace_probe_group_name(&tu->tp),
+	seq_printf(m, "%c:%s/%s %s:0x%0*llx", c, trace_probe_group_name(&tu->tp),
 			trace_probe_name(&tu->tp), tu->filename,
-			(int)(sizeof(void *) * 2), tu->offset);
+			(int)(sizeof(void *) * 2), tu->consumer.offset);
 
-	if (tu->ref_ctr_offset)
-		seq_printf(m, "(0x%lx)", tu->ref_ctr_offset);
+	if (tu->consumer.ref_ctr_offset)
+		seq_printf(m, "(0x%llx)", tu->consumer.ref_ctr_offset);
 
 	for (i = 0; i < tu->tp.nr_args; i++)
 		seq_printf(m, " %s=%s", tu->tp.args[i].name, tu->tp.args[i].comm);
@@ -1089,12 +1087,7 @@ 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->consumer);
 	if (ret)
 		tu->inode = NULL;
 
@@ -1112,7 +1105,7 @@ static void __probe_event_disable(struct trace_probe *tp)
 		if (!tu->inode)
 			continue;
 
-		uprobe_unregister(tu->inode, tu->offset, &tu->consumer);
+		uprobe_unregister(tu->inode, &tu->consumer);
 		tu->inode = NULL;
 	}
 }
@@ -1310,7 +1303,7 @@ static int uprobe_perf_close(struct trace_event_call *call,
 		return 0;
 
 	list_for_each_entry(tu, trace_probe_probe_list(tp), tp.list) {
-		ret = uprobe_apply(tu->inode, tu->offset, &tu->consumer, false);
+		ret = uprobe_apply(tu->inode, tu->consumer.offset, &tu->consumer, false);
 		if (ret)
 			break;
 	}
@@ -1334,7 +1327,7 @@ static int uprobe_perf_open(struct trace_event_call *call,
 		return 0;
 
 	list_for_each_entry(tu, trace_probe_probe_list(tp), tp.list) {
-		err = uprobe_apply(tu->inode, tu->offset, &tu->consumer, true);
+		err = uprobe_apply(tu->inode, tu->consumer.offset, &tu->consumer, true);
 		if (err) {
 			uprobe_perf_close(call, event);
 			break;
@@ -1464,7 +1457,7 @@ int bpf_get_uprobe_info(const struct perf_event *event, u32 *fd_type,
 	*fd_type = is_ret_probe(tu) ? BPF_FD_TYPE_URETPROBE
 				    : BPF_FD_TYPE_UPROBE;
 	*filename = tu->filename;
-	*probe_offset = tu->offset;
+	*probe_offset = tu->consumer.offset;
 	*probe_addr = 0;
 	return 0;
 }
@@ -1627,9 +1620,9 @@ create_local_trace_uprobe(char *name, unsigned long offs,
 		return ERR_CAST(tu);
 	}
 
-	tu->offset = offs;
+	tu->consumer.offset = offs;
 	tu->path = path;
-	tu->ref_ctr_offset = ref_ctr_offset;
+	tu->consumer.ref_ctr_offset = ref_ctr_offset;
 	tu->filename = kstrdup(name, GFP_KERNEL);
 	if (!tu->filename) {
 		ret = -ENOMEM;
diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
index b0132a342bb5..ca7122cdbcd3 100644
--- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
+++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
@@ -391,25 +391,24 @@ static int testmod_register_uprobe(loff_t offset)
 {
 	int err = -EBUSY;
 
-	if (uprobe.offset)
+	if (uprobe.consumer.offset)
 		return -EBUSY;
 
 	mutex_lock(&testmod_uprobe_mutex);
 
-	if (uprobe.offset)
+	if (uprobe.consumer.offset)
 		goto out;
 
 	err = kern_path("/proc/self/exe", LOOKUP_FOLLOW, &uprobe.path);
 	if (err)
 		goto out;
 
-	err = uprobe_register_refctr(d_real_inode(uprobe.path.dentry),
-				     offset, 0, &uprobe.consumer);
-	if (err)
+	uprobe.consumer.offset = offset;
+	err = uprobe_register(d_real_inode(uprobe.path.dentry), &uprobe.consumer);
+	if (err) {
 		path_put(&uprobe.path);
-	else
-		uprobe.offset = offset;
-
+		uprobe.consumer.offset = 0;
+	}
 out:
 	mutex_unlock(&testmod_uprobe_mutex);
 	return err;
@@ -419,10 +418,9 @@ static void testmod_unregister_uprobe(void)
 {
 	mutex_lock(&testmod_uprobe_mutex);
 
-	if (uprobe.offset) {
-		uprobe_unregister(d_real_inode(uprobe.path.dentry),
-				  uprobe.offset, &uprobe.consumer);
-		uprobe.offset = 0;
+	if (uprobe.consumer.offset) {
+		uprobe_unregister(d_real_inode(uprobe.path.dentry), &uprobe.consumer);
+		uprobe.consumer.offset = 0;
 	}
 
 	mutex_unlock(&testmod_uprobe_mutex);
-- 
2.43.0





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