team: introduce two default team_modeop functions and use them in modes

[cascardo/linux.git] / mm / bounce.c

diff --git a/mm/bounce.c b/mm/bounce.c
index 0420867..5f89017 100644 (file)
--- a/mm/bounce.c
+++ b/mm/bounce.c
@@ -178,8 +178,45 @@ static void bounce_end_io_read_isa(struct bio *bio, int err)
        __bounce_end_io_read(bio, isa_page_pool, err);
 }
 
+#ifdef CONFIG_NEED_BOUNCE_POOL
+static int must_snapshot_stable_pages(struct request_queue *q, struct bio *bio)
+{
+       struct page *page;
+       struct backing_dev_info *bdi;
+       struct address_space *mapping;
+       struct bio_vec *from;
+       int i;
+
+       if (bio_data_dir(bio) != WRITE)
+               return 0;
+
+       if (!bdi_cap_stable_pages_required(&q->backing_dev_info))
+               return 0;
+
+       /*
+        * Based on the first page that has a valid mapping, decide whether or
+        * not we have to employ bounce buffering to guarantee stable pages.
+        */
+       bio_for_each_segment(from, bio, i) {
+               page = from->bv_page;
+               mapping = page_mapping(page);
+               if (!mapping)
+                       continue;
+               bdi = mapping->backing_dev_info;
+               return mapping->host->i_sb->s_flags & MS_SNAP_STABLE;
+       }
+
+       return 0;
+}
+#else
+static int must_snapshot_stable_pages(struct request_queue *q, struct bio *bio)
+{
+       return 0;
+}
+#endif /* CONFIG_NEED_BOUNCE_POOL */
+
 static void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig,
-                              mempool_t *pool)
+                              mempool_t *pool, int force)
 {
        struct page *page;
        struct bio *bio = NULL;
@@ -192,7 +229,7 @@ static void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig,
                /*
                 * is destination page below bounce pfn?
                 */
-               if (page_to_pfn(page) <= queue_bounce_pfn(q))
+               if (page_to_pfn(page) <= queue_bounce_pfn(q) && !force)
                        continue;
 
                /*
@@ -270,6 +307,7 @@ static void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig,
 
 void blk_queue_bounce(struct request_queue *q, struct bio **bio_orig)
 {
+       int must_bounce;
        mempool_t *pool;
 
        /*
@@ -278,13 +316,15 @@ void blk_queue_bounce(struct request_queue *q, struct bio **bio_orig)
        if (!bio_has_data(*bio_orig))
                return;
 
+       must_bounce = must_snapshot_stable_pages(q, *bio_orig);
+
        /*
         * for non-isa bounce case, just check if the bounce pfn is equal
         * to or bigger than the highest pfn in the system -- in that case,
         * don't waste time iterating over bio segments
         */
        if (!(q->bounce_gfp & GFP_DMA)) {
-               if (queue_bounce_pfn(q) >= blk_max_pfn)
+               if (queue_bounce_pfn(q) >= blk_max_pfn && !must_bounce)
                        return;
                pool = page_pool;
        } else {
@@ -295,7 +335,7 @@ void blk_queue_bounce(struct request_queue *q, struct bio **bio_orig)
        /*
         * slow path
         */
-       __blk_queue_bounce(q, bio_orig, pool);
+       __blk_queue_bounce(q, bio_orig, pool, must_bounce);
 }
 
 EXPORT_SYMBOL(blk_queue_bounce);