From 325d73bf8fea8af2227240b7305253fb052d3a68 Mon Sep 17 00:00:00 2001 From: Bob Liu Date: Fri, 3 Apr 2015 14:42:58 +0800 Subject: xen/blkback: safely unmap purge persistent grants Commit c43cf3ea8385 ("xen-blkback: safely unmap grants in case they are still in use") use gnttab_unmap_refs_async() to wait until the mapped pages are no longer in use before unmapping them, but that commit missed the persistent case. Purge persistent pages can't be unmapped either unless no longer in use. Signed-off-by: Bob Liu Acked-by: Roger Pau Monné Signed-off-by: David Vrabel --- drivers/block/xen-blkback/blkback.c | 24 ++++++++++++++++++------ 1 file changed, 18 insertions(+), 6 deletions(-) (limited to 'drivers/block') diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c index bd2b3bbbb22c..48e98f2712b5 100644 --- a/drivers/block/xen-blkback/blkback.c +++ b/drivers/block/xen-blkback/blkback.c @@ -329,8 +329,18 @@ void xen_blkbk_unmap_purged_grants(struct work_struct *work) struct gnttab_unmap_grant_ref unmap[BLKIF_MAX_SEGMENTS_PER_REQUEST]; struct page *pages[BLKIF_MAX_SEGMENTS_PER_REQUEST]; struct persistent_gnt *persistent_gnt; - int ret, segs_to_unmap = 0; + 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; while(!list_empty(&blkif->persistent_purge_list)) { persistent_gnt = list_first_entry(&blkif->persistent_purge_list, @@ -346,17 +356,19 @@ void xen_blkbk_unmap_purged_grants(struct work_struct *work) pages[segs_to_unmap] = persistent_gnt->page; if (++segs_to_unmap == BLKIF_MAX_SEGMENTS_PER_REQUEST) { - ret = gnttab_unmap_refs(unmap, NULL, pages, - segs_to_unmap); - BUG_ON(ret); + unmap_data.count = segs_to_unmap; + gnttab_unmap_refs_async(&unmap_data); + wait_for_completion(&unmap_completion); + put_free_pages(blkif, pages, segs_to_unmap); segs_to_unmap = 0; } kfree(persistent_gnt); } if (segs_to_unmap > 0) { - ret = gnttab_unmap_refs(unmap, NULL, pages, segs_to_unmap); - BUG_ON(ret); + unmap_data.count = segs_to_unmap; + gnttab_unmap_refs_async(&unmap_data); + wait_for_completion(&unmap_completion); put_free_pages(blkif, pages, segs_to_unmap); } } -- cgit v1.2.3 From b44166cd46e28dd608d5baa5873047a40f32919c Mon Sep 17 00:00:00 2001 From: Bob Liu Date: Fri, 3 Apr 2015 14:42:59 +0800 Subject: xen/grant: introduce func gnttab_unmap_refs_sync() There are several place using gnttab async unmap and wait for completion, so move the common code to a function gnttab_unmap_refs_sync(). Signed-off-by: Bob Liu Acked-by: Roger Pau Monné Acked-by: Konrad Rzeszutek Wilk Signed-off-by: David Vrabel --- 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(-) (limited to 'drivers/block') diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c index 48e98f2712b5..713fc9ff1149 100644 --- a/drivers/block/xen-blkback/blkback.c +++ b/drivers/block/xen-blkback/blkback.c @@ -265,17 +265,6 @@ 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) { @@ -285,12 +274,7 @@ 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; @@ -310,8 +294,7 @@ 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; @@ -332,12 +315,7 @@ 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; @@ -357,9 +335,7 @@ 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; } @@ -367,8 +343,7 @@ 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 d5bb1a33d0a3..89274850741b 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 17972fbacddc..b1c7170e5c9e 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 143ca5ffab7a..4478f4b4aae2 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 -- cgit v1.2.3