mm/mm_init: replace simple_strtoul with kstrtobool in set_hashdist

Use bool for 'hashdist' and replace simple_strtoul() with kstrtobool() for
parsing the 'hashdist=' boot parameter.  Unlike simple_strtoul(), which
returns an unsigned long, kstrtobool() converts the string directly to
bool and avoids implicit casting.

Check the return value of kstrtobool() and reject invalid values.  This
adds error handling while preserving behavior for existing values, and
removes use of the deprecated simple_strtoul() helper.  The current code
silently sets 'hashdist = 0' if parsing fails, instead of leaving the
default value (HASHDIST_DEFAULT) unchanged.

Additionally, kstrtobool() accepts common boolean strings such as "on" and
"off".

Link: https://lkml.kernel.org/r/20251217110214.50807-1-thorsten.blum@linux.dev
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/include/linux/memblock.h b/include/linux/memblock.h
index 221118b5a16e1be0020d6236a9128b4c29d3a5f3..6ec5e9ac06992a0dd1412ec2f32c181af36eeabd 100644 (file)
--- a/include/linux/memblock.h
+++ b/include/linux/memblock.h
@@ -598,9 +598,9 @@ extern void *alloc_large_system_hash(const char *tablename,
  */
 #ifdef CONFIG_NUMA
 #define HASHDIST_DEFAULT IS_ENABLED(CONFIG_64BIT)
-extern int hashdist;           /* Distribute hashes across NUMA nodes? */
+extern bool hashdist;          /* Distribute hashes across NUMA nodes? */
 #else
-#define hashdist (0)
+#define hashdist (false)
 #endif
 
 #ifdef CONFIG_MEMTEST

diff --git a/mm/mm_init.c b/mm/mm_init.c
index fc2a6f1e518f1a33d45796907a4d6426f61eb37b..d86248566a56baac9ac95d1ab2805d0cabafe56f 100644 (file)
--- a/mm/mm_init.c
+++ b/mm/mm_init.c
@@ -646,21 +646,18 @@ int __meminit early_pfn_to_nid(unsigned long pfn)
        return nid;
 }
 
-int hashdist = HASHDIST_DEFAULT;
+bool hashdist = HASHDIST_DEFAULT;
 
 static int __init set_hashdist(char *str)
 {
-       if (!str)
-               return 0;
-       hashdist = simple_strtoul(str, &str, 0);
-       return 1;
+       return kstrtobool(str, &hashdist) == 0;
 }
 __setup("hashdist=", set_hashdist);
 
 static inline void fixup_hashdist(void)
 {
        if (num_node_state(N_MEMORY) == 1)
-               hashdist = 0;
+               hashdist = false;
 }
 #else
 static inline void fixup_hashdist(void) {}