alloc_tag: introduce shutdown_mem_profiling helper function

Implement a helper function to disable memory allocation profiling and use
it when creation of /proc/allocinfo fails. Ensure /proc/allocinfo does
not get created when memory allocation profiling is disabled.

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Suren Baghdasaryan <[e-mail]>
Reviewed-by: Pasha Tatashin <[e-mail]>
Cc: Ard Biesheuvel <[e-mail]>
Cc: Arnd Bergmann <[e-mail]>
Cc: Borislav Petkov (AMD) <[e-mail]>
Cc: Christoph Hellwig <[e-mail]>
Cc: Daniel Gomez <[e-mail]>
Cc: David Hildenbrand <[e-mail]>
Cc: Davidlohr Bueso <[e-mail]>
Cc: David Rientjes <[e-mail]>
Cc: Dennis Zhou <[e-mail]>
Cc: Johannes Weiner <[e-mail]>
Cc: John Hubbard <[e-mail]>
Cc: Jonathan Corbet <[e-mail]>
Cc: Joonsoo Kim <[e-mail]>
Cc: Kalesh Singh <[e-mail]>
Cc: Kees Cook <[e-mail]>
Cc: Kent Overstreet <[e-mail]>
Cc: Liam R. Howlett <[e-mail]>
Cc: Luis Chamberlain <[e-mail]>
Cc: Matthew Wilcox <[e-mail]>
Cc: Michal Hocko <[e-mail]>
Cc: Mike Rapoport (Microsoft) <[e-mail]>
Cc: Minchan Kim <[e-mail]>
Cc: Paul E. McKenney <[e-mail]>
Cc: Petr Pavlu <[e-mail]>
Cc: Roman Gushchin <[e-mail]>
Cc: Sami Tolvanen <[e-mail]>
Cc: Sourav Panda <[e-mail]>
Cc: Steven Rostedt (Google) <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Cc: Thomas Huth <[e-mail]>
Cc: Uladzislau Rezki (Sony) <[e-mail]>
Cc: Vlastimil Babka <[e-mail]>
Cc: Xiongwei Song <[e-mail]>
Cc: Yu Zhao <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>

lib/alloc_tag.c

···
 #include <linux/seq_buf.h>
 #include <linux/seq_file.h>
 
+#define ALLOCINFO_FILE_NAME		"allocinfo"
+
+#ifdef CONFIG_MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT
+static bool mem_profiling_support __meminitdata = true;
+#else
+static bool mem_profiling_support __meminitdata;
+#endif
+
 static struct codetag_type *alloc_tag_cttype;
 
 DEFINE_PER_CPU(struct alloc_tag_counters, _shared_alloc_tag);
···
 	return nr;
 }
 
+static void __init shutdown_mem_profiling(void)
+{
+	if (mem_alloc_profiling_enabled())
+		static_branch_disable(&mem_alloc_profiling_key);
+
+	if (!mem_profiling_support)
+		return;
+
+	mem_profiling_support = false;
+}
+
 static void __init procfs_init(void)
 {
-	proc_create_seq("allocinfo", 0400, NULL, &allocinfo_seq_op);
+	if (!mem_profiling_support)
+		return;
+
+	if (!proc_create_seq(ALLOCINFO_FILE_NAME, 0400, NULL, &allocinfo_seq_op)) {
+		pr_err("Failed to create %s file\n", ALLOCINFO_FILE_NAME);
+		shutdown_mem_profiling();
+	}
 }
 
 static bool alloc_tag_module_unload(struct codetag_type *cttype,
···
 
 	return module_unused;
 }
-
-#ifdef CONFIG_MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT
-static bool mem_profiling_support __meminitdata = true;
-#else
-static bool mem_profiling_support __meminitdata;
-#endif
 
 static int __init setup_early_mem_profiling(char *str)
 {