[Xen-devel] [PATCH v2 2/2] xen/grant: introduce func gnttab_unmap_refs_sync()

[Bob Liu <bob.liu@xxxxxxxxxx>]

There are several place using gnttab async unmap and wait for
completion, so move the common code to a function
gnttab_unmap_refs_sync().

v2: Rename to gnttab_unmap_refs_sync()

Signed-off-by: Bob Liu <bob.liu@xxxxxxxxxx>
---
 drivers/block/xen-blkback/blkback.c |   31 +++----------------------------
 drivers/xen/gntdev.c                |   28 +++-------------------------
 drivers/xen/grant-table.c           |   28 ++++++++++++++++++++++++++++
 include/xen/grant_table.h           |    1 +
 4 files changed, 35 insertions(+), 53 deletions(-)

diff --git a/drivers/block/xen-blkback/blkback.c 
b/drivers/block/xen-blkback/blkback.c
index f59d7c3..a49c500 100644
--- a/drivers/block/xen-blkback/blkback.c
+++ b/drivers/block/xen-blkback/blkback.c
@@ -263,17 +263,6 @@ static void put_persistent_gnt(struct xen_blkif *blkif,
        atomic_dec(&blkif->persistent_gnt_in_use);
 }
 
-static void free_persistent_gnts_unmap_callback(int result,
-                                               struct gntab_unmap_queue_data 
*data)
-{
-       struct completion *c = data->data;
-
-       /* BUG_ON used to reproduce existing behaviour,
-          but is this the best way to deal with this? */
-       BUG_ON(result);
-       complete(c);
-}
-
 static void free_persistent_gnts(struct xen_blkif *blkif, struct rb_root *root,
                                  unsigned int num)
 {
@@ -283,12 +272,7 @@ static void free_persistent_gnts(struct xen_blkif *blkif, 
struct rb_root *root,
        struct rb_node *n;
        int segs_to_unmap = 0;
        struct gntab_unmap_queue_data unmap_data;
-       struct completion unmap_completion;
-
-       init_completion(&unmap_completion);
 
-       unmap_data.data = &unmap_completion;
-       unmap_data.done = &free_persistent_gnts_unmap_callback;
        unmap_data.pages = pages;
        unmap_data.unmap_ops = unmap;
        unmap_data.kunmap_ops = NULL;
@@ -308,8 +292,7 @@ static void free_persistent_gnts(struct xen_blkif *blkif, 
struct rb_root *root,
                        !rb_next(&persistent_gnt->node)) {
 
                        unmap_data.count = segs_to_unmap;
-                       gnttab_unmap_refs_async(&unmap_data);
-                       wait_for_completion(&unmap_completion);
+                       BUG_ON(gnttab_unmap_refs_sync(&unmap_data));
 
                        put_free_pages(blkif, pages, segs_to_unmap);
                        segs_to_unmap = 0;
@@ -330,12 +313,7 @@ void xen_blkbk_unmap_purged_grants(struct work_struct 
*work)
        int segs_to_unmap = 0;
        struct xen_blkif *blkif = container_of(work, typeof(*blkif), 
persistent_purge_work);
        struct gntab_unmap_queue_data unmap_data;
-       struct completion unmap_completion;
 
-       init_completion(&unmap_completion);
-
-       unmap_data.data = &unmap_completion;
-       unmap_data.done = &free_persistent_gnts_unmap_callback;
        unmap_data.pages = pages;
        unmap_data.unmap_ops = unmap;
        unmap_data.kunmap_ops = NULL;
@@ -355,9 +333,7 @@ void xen_blkbk_unmap_purged_grants(struct work_struct *work)
 
                if (++segs_to_unmap == BLKIF_MAX_SEGMENTS_PER_REQUEST) {
                        unmap_data.count = segs_to_unmap;
-                       gnttab_unmap_refs_async(&unmap_data);
-                       wait_for_completion(&unmap_completion);
-
+                       BUG_ON(gnttab_unmap_refs_sync(&unmap_data));
                        put_free_pages(blkif, pages, segs_to_unmap);
                        segs_to_unmap = 0;
                }
@@ -365,8 +341,7 @@ void xen_blkbk_unmap_purged_grants(struct work_struct *work)
        }
        if (segs_to_unmap > 0) {
                unmap_data.count = segs_to_unmap;
-               gnttab_unmap_refs_async(&unmap_data);
-               wait_for_completion(&unmap_completion);
+               BUG_ON(gnttab_unmap_refs_sync(&unmap_data));
                put_free_pages(blkif, pages, segs_to_unmap);
        }
 }
diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index d5bb1a3..8927485 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -327,30 +327,10 @@ static int map_grant_pages(struct grant_map *map)
        return err;
 }
 
-struct unmap_grant_pages_callback_data
-{
-       struct completion completion;
-       int result;
-};
-
-static void unmap_grant_callback(int result,
-                                struct gntab_unmap_queue_data *data)
-{
-       struct unmap_grant_pages_callback_data* d = data->data;
-
-       d->result = result;
-       complete(&d->completion);
-}
-
 static int __unmap_grant_pages(struct grant_map *map, int offset, int pages)
 {
        int i, err = 0;
        struct gntab_unmap_queue_data unmap_data;
-       struct unmap_grant_pages_callback_data data;
-
-       init_completion(&data.completion);
-       unmap_data.data = &data;
-       unmap_data.done= &unmap_grant_callback;
 
        if (map->notify.flags & UNMAP_NOTIFY_CLEAR_BYTE) {
                int pgno = (map->notify.addr >> PAGE_SHIFT);
@@ -367,11 +347,9 @@ static int __unmap_grant_pages(struct grant_map *map, int 
offset, int pages)
        unmap_data.pages = map->pages + offset;
        unmap_data.count = pages;
 
-       gnttab_unmap_refs_async(&unmap_data);
-
-       wait_for_completion(&data.completion);
-       if (data.result)
-               return data.result;
+       err = gnttab_unmap_refs_sync(&unmap_data);
+       if (err)
+               return err;
 
        for (i = 0; i < pages; i++) {
                if (map->unmap_ops[offset+i].status)
diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index 17972fb..b1c7170 100644
--- a/drivers/xen/grant-table.c
+++ b/drivers/xen/grant-table.c
@@ -123,6 +123,11 @@ struct gnttab_ops {
        int (*query_foreign_access)(grant_ref_t ref);
 };
 
+struct unmap_refs_callback_data {
+       struct completion completion;
+       int result;
+};
+
 static struct gnttab_ops *gnttab_interface;
 
 static int grant_table_version;
@@ -863,6 +868,29 @@ void gnttab_unmap_refs_async(struct 
gntab_unmap_queue_data* item)
 }
 EXPORT_SYMBOL_GPL(gnttab_unmap_refs_async);
 
+static void unmap_refs_callback(int result,
+               struct gntab_unmap_queue_data *data)
+{
+       struct unmap_refs_callback_data *d = data->data;
+
+       d->result = result;
+       complete(&d->completion);
+}
+
+int gnttab_unmap_refs_sync(struct gntab_unmap_queue_data *item)
+{
+       struct unmap_refs_callback_data data;
+
+       init_completion(&data.completion);
+       item->data = &data;
+       item->done = &unmap_refs_callback;
+       gnttab_unmap_refs_async(item);
+       wait_for_completion(&data.completion);
+
+       return data.result;
+}
+EXPORT_SYMBOL_GPL(gnttab_unmap_refs_sync);
+
 static int gnttab_map_frames_v1(xen_pfn_t *frames, unsigned int nr_gframes)
 {
        int rc;
diff --git a/include/xen/grant_table.h b/include/xen/grant_table.h
index 143ca5f..4478f4b 100644
--- a/include/xen/grant_table.h
+++ b/include/xen/grant_table.h
@@ -191,6 +191,7 @@ int gnttab_unmap_refs(struct gnttab_unmap_grant_ref 
*unmap_ops,
                      struct gnttab_unmap_grant_ref *kunmap_ops,
                      struct page **pages, unsigned int count);
 void gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item);
+int gnttab_unmap_refs_sync(struct gntab_unmap_queue_data *item);
 
 
 /* Perform a batch of grant map/copy operations. Retry every batch slot
-- 
1.7.10.4


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