Revert "SA spill block cache"

The SA spill_cache was originally introduced to avoid the need to
perform large kmem or vmem allocations.  Instead a small dedicated
cache of preallocated SA buffers was kept.

This solution was viable while the maximum block size was limited
to 128K.  But with the planned increase of the maximum block size
to 16M callers need to migrate to the zio_buf_alloc().  However,
they should be aware this interface is expected to change again
once the zio buffers are fully backed by scatter-gather lists.

Alternately, if the callers know these buffers will never be large
or be infrequently accessed they may kmem_alloc() or vmem_alloc()
the needed temporary space.

This change has the additional benegit of bringing the code back
inline with the upstream Illumos source.

Signed-off-by: Brian Behlendorf <[email protected]>

3 files changed, 12 insertions, 27 deletions

diff --git a/module/zfs/sa.c b/module/zfs/sa.c
index ea68e40a2..1263d37ab 100644
--- a/module/zfs/sa.c
+++ b/module/zfs/sa.c
@@ -202,7 +202,6 @@ sa_attr_type_t sa_dummy_zpl_layout[] = { 0 };
 
 static int sa_legacy_attr_count = 16;
 static kmem_cache_t *sa_cache = NULL;
-static kmem_cache_t *spill_cache = NULL;
 
 /*ARGSUSED*/
 static int
@@ -234,8 +233,6 @@ sa_cache_init(void)
 	sa_cache = kmem_cache_create("sa_cache",
 	    sizeof (sa_handle_t), 0, sa_cache_constructor,
 	    sa_cache_destructor, NULL, NULL, NULL, 0);
-	spill_cache = kmem_cache_create("spill_cache",
-	    SPA_MAXBLOCKSIZE, 0, NULL, NULL, NULL, NULL, NULL, 0);
 }
 
 void
@@ -243,21 +240,6 @@ sa_cache_fini(void)
 {
 	if (sa_cache)
 		kmem_cache_destroy(sa_cache);
-
-	if (spill_cache)
-		kmem_cache_destroy(spill_cache);
-}
-
-void *
-sa_spill_alloc(int flags)
-{
-	return (kmem_cache_alloc(spill_cache, flags));
-}
-
-void
-sa_spill_free(void *obj)
-{
-	kmem_cache_free(spill_cache, obj);
 }
 
 static int
@@ -1672,6 +1654,7 @@ sa_modify_attrs(sa_handle_t *hdl, sa_attr_type_t newattr,
 	void *old_data[2];
 	int bonus_attr_count = 0;
 	int bonus_data_size = 0;
+	int spill_data_size = 0;
 	int spill_attr_count = 0;
 	int error;
 	uint16_t length;
@@ -1701,8 +1684,8 @@ sa_modify_attrs(sa_handle_t *hdl, sa_attr_type_t newattr,
 	/* Bring spill buffer online if it isn't currently */
 
 	if ((error = sa_get_spill(hdl)) == 0) {
-		ASSERT3U(hdl->sa_spill->db_size, <=, SPA_MAXBLOCKSIZE);
-		old_data[1] = sa_spill_alloc(KM_SLEEP);
+		spill_data_size = hdl->sa_spill->db_size;
+		old_data[1] = zio_buf_alloc(spill_data_size);
 		bcopy(hdl->sa_spill->db_data, old_data[1],
 		    hdl->sa_spill->db_size);
 		spill_attr_count =
@@ -1787,7 +1770,7 @@ sa_modify_attrs(sa_handle_t *hdl, sa_attr_type_t newattr,
 	if (old_data[0])
 		kmem_free(old_data[0], bonus_data_size);
 	if (old_data[1])
-		sa_spill_free(old_data[1]);
+		zio_buf_free(old_data[1], spill_data_size);
 	kmem_free(attr_desc, sizeof (sa_bulk_attr_t) * attr_count);
 
 	return (error);
@@ -2077,8 +2060,6 @@ EXPORT_SYMBOL(sa_replace_all_by_template_locked);
 EXPORT_SYMBOL(sa_enabled);
 EXPORT_SYMBOL(sa_cache_init);
 EXPORT_SYMBOL(sa_cache_fini);
-EXPORT_SYMBOL(sa_spill_alloc);
-EXPORT_SYMBOL(sa_spill_free);
 EXPORT_SYMBOL(sa_set_sa_object);
 EXPORT_SYMBOL(sa_hdrsize);
 EXPORT_SYMBOL(sa_handle_lock);
diff --git a/module/zfs/zfs_sa.c b/module/zfs/zfs_sa.c
index ebe92bb3a..257ab4254 100644
--- a/module/zfs/zfs_sa.c
+++ b/module/zfs/zfs_sa.c
@@ -205,13 +205,13 @@ zfs_sa_get_xattr(znode_t *zp)
 			return (error);
 	}
 
-	obj = sa_spill_alloc(KM_SLEEP);
+	obj = zio_buf_alloc(size);
 
 	error = sa_lookup(zp->z_sa_hdl, SA_ZPL_DXATTR(zsb), obj, size);
 	if (error == 0)
 		error = nvlist_unpack(obj, size, &zp->z_xattr_cached, KM_SLEEP);
 
-	sa_spill_free(obj);
+	zio_buf_free(obj, size);
 
 	return (error);
 }
@@ -233,7 +233,7 @@ zfs_sa_set_xattr(znode_t *zp)
 	if (error)
 		goto out;
 
-	obj = sa_spill_alloc(KM_SLEEP);
+	obj = zio_buf_alloc(size);
 
 	error = nvlist_pack(zp->z_xattr_cached, &obj, &size,
 	    NV_ENCODE_XDR, KM_SLEEP);
@@ -256,7 +256,7 @@ zfs_sa_set_xattr(znode_t *zp)
 			dmu_tx_commit(tx);
 	}
 out_free:
-	sa_spill_free(obj);
+	zio_buf_free(obj, size);
 out:
 	return (error);
 }
diff --git a/module/zfs/zio.c b/module/zfs/zio.c
index 6fa23d2fc..7dcb42006 100644
--- a/module/zfs/zio.c
+++ b/module/zfs/zio.c
@@ -3393,6 +3393,10 @@ EXPORT_SYMBOL(zio_handle_fault_injection);
 EXPORT_SYMBOL(zio_handle_device_injection);
 EXPORT_SYMBOL(zio_handle_label_injection);
 EXPORT_SYMBOL(zio_type_name);
+EXPORT_SYMBOL(zio_buf_alloc);
+EXPORT_SYMBOL(zio_data_buf_alloc);
+EXPORT_SYMBOL(zio_buf_free);
+EXPORT_SYMBOL(zio_data_buf_free);
 
 module_param(zio_bulk_flags, int, 0644);
 MODULE_PARM_DESC(zio_bulk_flags, "Additional flags to pass to bulk buffers");