Linux 6.11: first arg to proc_handler is now const

Detect it, and use a macro to make sure we always match the prototype. Reviewed-by: Tony Hutter <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Rob Norris <[email protected]> Sponsored-by: https://despairlabs.com/sponsor/ Closes #16400
openzfs · Aug 14, 2024 · 2261952 · 2261952
1 parent 7e98d30
commit 2261952
Show file tree

Hide file tree

Showing 3 changed files with 44 additions and 3 deletions.
diff --git a/config/kernel-register_sysctl_table.m4 b/config/kernel-register_sysctl_table.m4
@@ -25,3 +25,36 @@ AC_DEFUN([ZFS_AC_KERNEL_REGISTER_SYSCTL_TABLE], [
 		AC_MSG_RESULT([no])
 	])
 ])
+
+dnl #
+dnl # Linux 6.11 makes const the ctl_table arg of proc_handler
+dnl #
+AC_DEFUN([ZFS_AC_KERNEL_SRC_PROC_HANDLER_CTL_TABLE_CONST], [
+	ZFS_LINUX_TEST_SRC([has_proc_handler_ctl_table_const], [
+		#include <linux/sysctl.h>
+
+		static int test_handler(
+		    const struct ctl_table *ctl __attribute((unused)),
+		    int write __attribute((unused)),
+		    void *buffer __attribute((unused)),
+		    size_t *lenp __attribute((unused)),
+		    loff_t *ppos __attribute((unused)))
+		{
+			return (0);
+		}
+	], [
+		proc_handler *ph __attribute((unused)) =
+		    &test_handler;
+	])
+])
+
+AC_DEFUN([ZFS_AC_KERNEL_PROC_HANDLER_CTL_TABLE_CONST], [
+	AC_MSG_CHECKING([whether proc_handler ctl_table arg is const])
+	ZFS_LINUX_TEST_RESULT([has_proc_handler_ctl_table_const], [
+		AC_MSG_RESULT([yes])
+		AC_DEFINE(HAVE_PROC_HANDLER_CTL_TABLE_CONST, 1,
+		    [proc_handler ctl_table arg is const])
+	], [
+		AC_MSG_RESULT([no])
+	])
+])
diff --git a/config/kernel.m4 b/config/kernel.m4
@@ -167,6 +167,7 @@ AC_DEFUN([ZFS_AC_KERNEL_TEST_SRC], [
 	ZFS_AC_KERNEL_SRC_WRITEPAGE_T
 	ZFS_AC_KERNEL_SRC_RECLAIMED
 	ZFS_AC_KERNEL_SRC_REGISTER_SYSCTL_TABLE
+	ZFS_AC_KERNEL_SRC_PROC_HANDLER_CTL_TABLE_CONST
 	ZFS_AC_KERNEL_SRC_COPY_SPLICE_READ
 	ZFS_AC_KERNEL_SRC_SYNC_BDEV
 	ZFS_AC_KERNEL_SRC_MM_PAGE_SIZE
@@ -319,6 +320,7 @@ AC_DEFUN([ZFS_AC_KERNEL_TEST_RESULT], [
 	ZFS_AC_KERNEL_WRITEPAGE_T
 	ZFS_AC_KERNEL_RECLAIMED
 	ZFS_AC_KERNEL_REGISTER_SYSCTL_TABLE
+	ZFS_AC_KERNEL_PROC_HANDLER_CTL_TABLE_CONST
 	ZFS_AC_KERNEL_COPY_SPLICE_READ
 	ZFS_AC_KERNEL_SYNC_BDEV
 	ZFS_AC_KERNEL_MM_PAGE_SIZE

diff --git a/module/os/linux/spl/spl-proc.c b/module/os/linux/spl/spl-proc.c
@@ -43,6 +43,12 @@ typedef struct ctl_table __no_const spl_ctl_table;
 typedef struct ctl_table spl_ctl_table;
 #endif
 
+#ifdef HAVE_PROC_HANDLER_CTL_TABLE_CONST
+#define	CONST_CTL_TABLE		const struct ctl_table
+#else
+#define	CONST_CTL_TABLE		struct ctl_table
+#endif
+
 static unsigned long table_min = 0;
 static unsigned long table_max = ~0;
 
@@ -60,7 +66,7 @@ struct proc_dir_entry *proc_spl_kstat = NULL;
 
 #ifdef DEBUG_KMEM
 static int
-proc_domemused(struct ctl_table *table, int write,
+proc_domemused(CONST_CTL_TABLE *table, int write,
     void __user *buffer, size_t *lenp, loff_t *ppos)
 {
 	int rc = 0;
@@ -88,7 +94,7 @@ proc_domemused(struct ctl_table *table, int write,
 #endif /* DEBUG_KMEM */
 
 static int
-proc_doslab(struct ctl_table *table, int write,
+proc_doslab(CONST_CTL_TABLE *table, int write,
     void __user *buffer, size_t *lenp, loff_t *ppos)
 {
 	int rc = 0;
@@ -135,7 +141,7 @@ proc_doslab(struct ctl_table *table, int write,
 }
 
 static int
-proc_dohostid(struct ctl_table *table, int write,
+proc_dohostid(CONST_CTL_TABLE *table, int write,
     void __user *buffer, size_t *lenp, loff_t *ppos)
 {
 	char *end, str[32];