A few fixes of callback typecasting (for the upcoming ClangCFI)

* zio: avoid callback typecasting
* zil: avoid zil_itxg_clean() callback typecasting
* zpl: decouple zpl_readpage() into two separate callbacks
* nvpair: explicitly declare callbacks for xdr_array()
* linux/zfs_nvops: don't use external iput() as a callback
* zcp_synctask: don't use fnvlist_free() as a callback
* zvol: don't use ops->zv_free() as a callback for taskq_dispatch()

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Mark Maybee <mark.maybee@delphix.com>
Signed-off-by: Alexander Lobakin <alobakin@pm.me>
Closes #12260

include/sys/zio.h

@@ -572,8 +572,8 @@ extern void zio_shrink(zio_t *zio, uint64_t size);
 
 extern int zio_wait(zio_t *zio);
 extern void zio_nowait(zio_t *zio);
-extern void zio_execute(zio_t *zio);
-extern void zio_interrupt(zio_t *zio);
+extern void zio_execute(void *zio);
+extern void zio_interrupt(void *zio);
 extern void zio_delay_init(zio_t *zio);
 extern void zio_delay_interrupt(zio_t *zio);
 extern void zio_deadman(zio_t *zio, char *tag);

module/nvpair/nvpair.c

@@ -3213,6 +3213,56 @@ nvs_xdr_nvl_fini(nvstream_t *nvs)
 	return (0);
 }
 
+/*
+ * xdrproc_t-compatible callbacks for xdr_array()
+ */
+
+#if defined(_KERNEL) && defined(__linux__) /* Linux kernel */
+
+#define	NVS_BUILD_XDRPROC_T(type)		\
+static bool_t					\
+nvs_xdr_nvp_##type(XDR *xdrs, void *ptr)	\
+{						\
+	return (xdr_##type(xdrs, ptr));		\
+}
+
+#elif !defined(_KERNEL) && defined(XDR_CONTROL) /* tirpc */
+
+#define	NVS_BUILD_XDRPROC_T(type)		\
+static bool_t					\
+nvs_xdr_nvp_##type(XDR *xdrs, ...)		\
+{						\
+	va_list args;				\
+	void *ptr;				\
+						\
+	va_start(args, xdrs);			\
+	ptr = va_arg(args, void *);		\
+	va_end(args);				\
+						\
+	return (xdr_##type(xdrs, ptr));		\
+}
+
+#else /* FreeBSD, sunrpc */
+
+#define	NVS_BUILD_XDRPROC_T(type)		\
+static bool_t					\
+nvs_xdr_nvp_##type(XDR *xdrs, void *ptr, ...)	\
+{						\
+	return (xdr_##type(xdrs, ptr));		\
+}
+
+#endif
+
+/* BEGIN CSTYLED */
+NVS_BUILD_XDRPROC_T(char);
+NVS_BUILD_XDRPROC_T(short);
+NVS_BUILD_XDRPROC_T(u_short);
+NVS_BUILD_XDRPROC_T(int);
+NVS_BUILD_XDRPROC_T(u_int);
+NVS_BUILD_XDRPROC_T(longlong_t);
+NVS_BUILD_XDRPROC_T(u_longlong_t);
+/* END CSTYLED */
+
 /*
  * The format of xdr encoded nvpair is:
  * encode_size, decode_size, name string, data type, nelem, data
@@ -3335,38 +3385,38 @@ nvs_xdr_nvp_op(nvstream_t *nvs, nvpair_t *nvp)
 	case DATA_TYPE_INT8_ARRAY:
 	case DATA_TYPE_UINT8_ARRAY:
 		ret = xdr_array(xdr, &buf, &nelem, buflen, sizeof (int8_t),
-		    (xdrproc_t)xdr_char);
+		    nvs_xdr_nvp_char);
 		break;
 
 	case DATA_TYPE_INT16_ARRAY:
 		ret = xdr_array(xdr, &buf, &nelem, buflen / sizeof (int16_t),
-		    sizeof (int16_t), (xdrproc_t)xdr_short);
+		    sizeof (int16_t), nvs_xdr_nvp_short);
 		break;
 
 	case DATA_TYPE_UINT16_ARRAY:
 		ret = xdr_array(xdr, &buf, &nelem, buflen / sizeof (uint16_t),
-		    sizeof (uint16_t), (xdrproc_t)xdr_u_short);
+		    sizeof (uint16_t), nvs_xdr_nvp_u_short);
 		break;
 
 	case DATA_TYPE_BOOLEAN_ARRAY:
 	case DATA_TYPE_INT32_ARRAY:
 		ret = xdr_array(xdr, &buf, &nelem, buflen / sizeof (int32_t),
-		    sizeof (int32_t), (xdrproc_t)xdr_int);
+		    sizeof (int32_t), nvs_xdr_nvp_int);
 		break;
 
 	case DATA_TYPE_UINT32_ARRAY:
 		ret = xdr_array(xdr, &buf, &nelem, buflen / sizeof (uint32_t),
-		    sizeof (uint32_t), (xdrproc_t)xdr_u_int);
+		    sizeof (uint32_t), nvs_xdr_nvp_u_int);
 		break;
 
 	case DATA_TYPE_INT64_ARRAY:
 		ret = xdr_array(xdr, &buf, &nelem, buflen / sizeof (int64_t),
-		    sizeof (int64_t), (xdrproc_t)xdr_longlong_t);
+		    sizeof (int64_t), nvs_xdr_nvp_longlong_t);
 		break;
 
 	case DATA_TYPE_UINT64_ARRAY:
 		ret = xdr_array(xdr, &buf, &nelem, buflen / sizeof (uint64_t),
-		    sizeof (uint64_t), (xdrproc_t)xdr_u_longlong_t);
+		    sizeof (uint64_t), nvs_xdr_nvp_u_longlong_t);
 		break;
 
 	case DATA_TYPE_STRING_ARRAY: {

module/os/linux/zfs/zfs_vnops_os.c

@@ -367,6 +367,12 @@ zfs_write_simple(znode_t *zp, const void *data, size_t len,
 	return (error);
 }
 
+static void
+zfs_rele_async_task(void *arg)
+{
+	iput(arg);
+}
+
 void
 zfs_zrele_async(znode_t *zp)
 {
@@ -386,7 +392,7 @@ zfs_zrele_async(znode_t *zp)
 	 */
 	if (!atomic_add_unless(&ip->i_count, -1, 1)) {
 		VERIFY(taskq_dispatch(dsl_pool_zrele_taskq(dmu_objset_pool(os)),
-		    (task_func_t *)iput, ip, TQ_SLEEP) != TASKQID_INVALID);
+		    zfs_rele_async_task, ip, TQ_SLEEP) != TASKQID_INVALID);
 	}
 }
 

module/os/linux/zfs/zpl_file.c

@@ -591,8 +591,8 @@ zpl_mmap(struct file *filp, struct vm_area_struct *vma)
  * only used to support mmap(2).  There will be an identical copy of the
  * data in the ARC which is kept up to date via .write() and .writepage().
  */
-static int
-zpl_readpage(struct file *filp, struct page *pp)
+static inline int
+zpl_readpage_common(struct page *pp)
 {
 	struct inode *ip;
 	struct page *pl[1];
@@ -620,6 +620,18 @@ zpl_readpage(struct file *filp, struct page *pp)
 	return (error);
 }
 
+static int
+zpl_readpage(struct file *filp, struct page *pp)
+{
+	return (zpl_readpage_common(pp));
+}
+
+static int
+zpl_readpage_filler(void *data, struct page *pp)
+{
+	return (zpl_readpage_common(pp));
+}
+
 /*
  * Populate a set of pages with data for the Linux page cache.  This
  * function will only be called for read ahead and never for demand
@@ -630,8 +642,7 @@ static int
 zpl_readpages(struct file *filp, struct address_space *mapping,
     struct list_head *pages, unsigned nr_pages)
 {
-	return (read_cache_pages(mapping, pages,
-	    (filler_t *)zpl_readpage, filp));
+	return (read_cache_pages(mapping, pages, zpl_readpage_filler, NULL));
 }
 
 static int

module/zfs/zcp_synctask.c

@@ -54,6 +54,12 @@ typedef struct zcp_synctask_info {
 	int blocks_modified;
 } zcp_synctask_info_t;
 
+static void
+zcp_synctask_cleanup(void *arg)
+{
+	fnvlist_free(arg);
+}
+
 /*
  * Generic synctask interface for channel program syncfuncs.
  *
@@ -275,7 +281,7 @@ zcp_synctask_snapshot(lua_State *state, boolean_t sync, nvlist_t *err_details)
 	fnvlist_add_boolean(ddsa.ddsa_snaps, dsname);
 
 	zcp_cleanup_handler_t *zch = zcp_register_cleanup(state,
-	    (zcp_cleanup_t *)&fnvlist_free, ddsa.ddsa_snaps);
+	    zcp_synctask_cleanup, ddsa.ddsa_snaps);
 
 	err = zcp_sync_task(state, dsl_dataset_snapshot_check,
 	    dsl_dataset_snapshot_sync, &ddsa, sync, dsname);
@@ -363,7 +369,7 @@ zcp_synctask_inherit_prop(lua_State *state, boolean_t sync,
 	fnvlist_add_boolean(dpsa->dpsa_props, prop);
 
 	zcp_cleanup_handler_t *zch = zcp_register_cleanup(state,
-	    (zcp_cleanup_t *)&fnvlist_free, dpsa->dpsa_props);
+	    zcp_synctask_cleanup, dpsa->dpsa_props);
 
 	err = zcp_sync_task(state, zcp_synctask_inherit_prop_check,
 	    zcp_synctask_inherit_prop_sync, &zipa, sync, dsname);
@@ -402,7 +408,7 @@ zcp_synctask_bookmark(lua_State *state, boolean_t sync, nvlist_t *err_details)
 	fnvlist_add_string(bmarks, new, source);
 
 	zcp_cleanup_handler_t *zch = zcp_register_cleanup(state,
-	    (zcp_cleanup_t *)&fnvlist_free, bmarks);
+	    zcp_synctask_cleanup, bmarks);
 
 	dsl_bookmark_create_arg_t dbca = {
 		.dbca_bmarks = bmarks,
@@ -467,8 +473,7 @@ zcp_synctask_wrapper(lua_State *state)
 	 * Make sure err_details is properly freed, even if a fatal error is
 	 * thrown during the synctask.
 	 */
-	zch = zcp_register_cleanup(state,
-	    (zcp_cleanup_t *)&fnvlist_free, err_details);
+	zch = zcp_register_cleanup(state, zcp_synctask_cleanup, err_details);
 
 	zcp_synctask_info_t *info = lua_touserdata(state, lua_upvalueindex(1));
 	boolean_t sync = lua_toboolean(state, lua_upvalueindex(2));

module/zfs/zil.c

@@ -1822,12 +1822,13 @@ zil_itx_destroy(itx_t *itx)
  * so no locks are needed.
  */
 static void
-zil_itxg_clean(itxs_t *itxs)
+zil_itxg_clean(void *arg)
 {
 	itx_t *itx;
 	list_t *list;
 	avl_tree_t *t;
 	void *cookie;
+	itxs_t *itxs = arg;
 	itx_async_node_t *ian;
 
 	list = &itxs->i_sync_list;
@@ -2047,7 +2048,7 @@ zil_clean(zilog_t *zilog, uint64_t synced_txg)
 	ASSERT3P(zilog->zl_dmu_pool, !=, NULL);
 	ASSERT3P(zilog->zl_dmu_pool->dp_zil_clean_taskq, !=, NULL);
 	taskqid_t id = taskq_dispatch(zilog->zl_dmu_pool->dp_zil_clean_taskq,
-	    (void (*)(void *))zil_itxg_clean, clean_me, TQ_NOSLEEP);
+	    zil_itxg_clean, clean_me, TQ_NOSLEEP);
 	if (id == TASKQID_INVALID)
 		zil_itxg_clean(clean_me);
 }

module/zfs/zio.c

@@ -1891,8 +1891,8 @@ zio_taskq_dispatch(zio_t *zio, zio_taskq_type_t q, boolean_t cutinline)
 	 * to dispatch the zio to another taskq at the same time.
 	 */
 	ASSERT(taskq_empty_ent(&zio->io_tqent));
-	spa_taskq_dispatch_ent(spa, t, q, (task_func_t *)zio_execute, zio,
-	    flags, &zio->io_tqent);
+	spa_taskq_dispatch_ent(spa, t, q, zio_execute, zio, flags,
+	    &zio->io_tqent);
 }
 
 static boolean_t
@@ -1923,7 +1923,7 @@ zio_issue_async(zio_t *zio)
 }
 
 void
-zio_interrupt(zio_t *zio)
+zio_interrupt(void *zio)
 {
 	zio_taskq_dispatch(zio, ZIO_TASKQ_INTERRUPT, B_FALSE);
 }
@@ -1981,8 +1981,8 @@ zio_delay_interrupt(zio_t *zio)
 				 * OpenZFS's timeout_generic().
 				 */
 				tid = taskq_dispatch_delay(system_taskq,
-				    (task_func_t *)zio_interrupt,
-				    zio, TQ_NOSLEEP, expire_at_tick);
+				    zio_interrupt, zio, TQ_NOSLEEP,
+				    expire_at_tick);
 				if (tid == TASKQID_INVALID) {
 					/*
 					 * Couldn't allocate a task.  Just
@@ -2103,7 +2103,7 @@ static zio_pipe_stage_t *zio_pipeline[];
  * it is externally visible.
  */
 void
-zio_execute(zio_t *zio)
+zio_execute(void *zio)
 {
 	fstrans_cookie_t cookie;
 
@@ -2292,8 +2292,9 @@ zio_nowait(zio_t *zio)
  */
 
 static void
-zio_reexecute(zio_t *pio)
+zio_reexecute(void *arg)
 {
+	zio_t *pio = arg;
 	zio_t *cio, *cio_next;
 
 	ASSERT(pio->io_child_type == ZIO_CHILD_LOGICAL);
@@ -4788,8 +4789,7 @@ zio_done(zio_t *zio)
 			ASSERT(taskq_empty_ent(&zio->io_tqent));
 			spa_taskq_dispatch_ent(zio->io_spa,
 			    ZIO_TYPE_CLAIM, ZIO_TASKQ_ISSUE,
-			    (task_func_t *)zio_reexecute, zio, 0,
-			    &zio->io_tqent);
+			    zio_reexecute, zio, 0, &zio->io_tqent);
 		}
 		return (NULL);
 	}

module/zfs/zvol.c

@@ -1195,6 +1195,12 @@ zvol_create_minor(const char *name)
  * Remove minors for specified dataset including children and snapshots.
  */
 
+static void
+zvol_free_task(void *arg)
+{
+	ops->zv_free(arg);
+}
+
 void
 zvol_remove_minors_impl(const char *name)
 {
@@ -1243,8 +1249,8 @@ zvol_remove_minors_impl(const char *name)
 			mutex_exit(&zv->zv_state_lock);
 
 			/* Try parallel zv_free, if failed do it in place */
-			t = taskq_dispatch(system_taskq,
-			    (task_func_t *)ops->zv_free, zv, TQ_SLEEP);
+			t = taskq_dispatch(system_taskq, zvol_free_task, zv,
+			    TQ_SLEEP);
 			if (t == TASKQID_INVALID)
 				list_insert_head(&free_list, zv);
 		} else {