From 60948de1ef976aabaa3630707bcc8b5867508507 Mon Sep 17 00:00:00 2001
From: Brian Behlendorf <behlendorf1@llnl.gov>
Date: Thu, 26 Aug 2010 10:58:36 -0700
Subject: [PATCH] Fix stack noinline

Certain function must never be automatically inlined by gcc because
they are stack heavy or called recursively.  This patch flags all
such functions I've found as 'noinline' to prevent gcc from making
the optimization.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
---
 lib/libzpool/include/sys/zfs_context.h |  6 ++++++
 module/zfs/dbuf.c                      | 12 ++++++++++--
 module/zfs/dmu_send.c                  | 10 +++++-----
 3 files changed, 21 insertions(+), 7 deletions(-)

diff --git a/lib/libzpool/include/sys/zfs_context.h b/lib/libzpool/include/sys/zfs_context.h
index 55b117c218a1..f2776566c076 100644
--- a/lib/libzpool/include/sys/zfs_context.h
+++ b/lib/libzpool/include/sys/zfs_context.h
@@ -75,6 +75,12 @@ extern "C" {
 #include <sys/sysevent/dev.h>
 #include <sys/sunddi.h>
 
+/*
+ * Stack
+ */
+
+#define  noinline	__attribute__((noinline))
+
 /*
  * Debugging
  */
diff --git a/module/zfs/dbuf.c b/module/zfs/dbuf.c
index add2bc36d3d9..c1b27d4ef338 100644
--- a/module/zfs/dbuf.c
+++ b/module/zfs/dbuf.c
@@ -2291,7 +2291,11 @@ dbuf_check_blkptr(dnode_t *dn, dmu_buf_impl_t *db)
 	}
 }
 
-static void
+/* dbuf_sync_indirect() is called recursively from dbuf_sync_list() so it
+ * is critical the we not allow the compiler to inline this function in to
+ * dbuf_sync_list() thereby drastically bloating the stack usage.
+ */
+noinline static void
 dbuf_sync_indirect(dbuf_dirty_record_t *dr, dmu_tx_t *tx)
 {
 	dmu_buf_impl_t *db = dr->dr_dbuf;
@@ -2334,7 +2338,11 @@ dbuf_sync_indirect(dbuf_dirty_record_t *dr, dmu_tx_t *tx)
 	zio_nowait(zio);
 }
 
-static void
+/* dbuf_sync_leaf() is called recursively from dbuf_sync_list() so it is
+ * critical the we not allow the compiler to inline this function in to
+ * dbuf_sync_list() thereby drastically bloating the stack usage.
+ */
+noinline static void
 dbuf_sync_leaf(dbuf_dirty_record_t *dr, dmu_tx_t *tx)
 {
 	arc_buf_t **datap = &dr->dt.dl.dr_data;
diff --git a/module/zfs/dmu_send.c b/module/zfs/dmu_send.c
index dc93dea853e0..f13cfd316f90 100644
--- a/module/zfs/dmu_send.c
+++ b/module/zfs/dmu_send.c
@@ -937,7 +937,7 @@ restore_read(struct restorearg *ra, int len)
 	return (rv);
 }
 
-static void
+noinline static void
 backup_byteswap(dmu_replay_record_t *drr)
 {
 #define	DO64(X) (drr->drr_u.X = BSWAP_64(drr->drr_u.X))
@@ -1019,7 +1019,7 @@ backup_byteswap(dmu_replay_record_t *drr)
 #undef DO32
 }
 
-static int
+noinline static int
 restore_object(struct restorearg *ra, objset_t *os, struct drr_object *drro)
 {
 	int err;
@@ -1103,7 +1103,7 @@ restore_object(struct restorearg *ra, objset_t *os, struct drr_object *drro)
 }
 
 /* ARGSUSED */
-static int
+noinline static int
 restore_freeobjects(struct restorearg *ra, objset_t *os,
     struct drr_freeobjects *drrfo)
 {
@@ -1127,7 +1127,7 @@ restore_freeobjects(struct restorearg *ra, objset_t *os,
 	return (0);
 }
 
-static int
+noinline static int
 restore_write(struct restorearg *ra, objset_t *os,
     struct drr_write *drrw)
 {
@@ -1273,7 +1273,7 @@ restore_spill(struct restorearg *ra, objset_t *os, struct drr_spill *drrs)
 }
 
 /* ARGSUSED */
-static int
+noinline static int
 restore_free(struct restorearg *ra, objset_t *os,
     struct drr_free *drrf)
 {