Merge git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dm

* git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dm:
  dm kcopyd: return client directly and not through a pointer
  dm kcopyd: reserve fewer pages
  dm io: use fixed initial mempool size
  dm kcopyd: alloc pages from the main page allocator
  dm kcopyd: add gfp parm to alloc_pl
  dm kcopyd: remove superfluous page allocation spinlock
  dm kcopyd: preallocate sub jobs to avoid deadlock
  dm kcopyd: avoid pointless job splitting
  dm mpath: do not fail paths after integrity errors
  dm table: reject devices without request fns
  dm table: allow targets to support discards internally

11 files changed, 144 insertions, 124 deletions

diff --git a/drivers/md/dm-io.c b/drivers/md/dm-io.c
index 76a5af00a26..2067288f61f 100644
--- a/drivers/md/dm-io.c
+++ b/drivers/md/dm-io.c
@@ -19,6 +19,8 @@
 #define DM_MSG_PREFIX "io"
 
 #define DM_IO_MAX_REGIONS       BITS_PER_LONG
+#define MIN_IOS         16
+#define MIN_BIOS        16
 
 struct dm_io_client {
         mempool_t *pool;
@@ -41,33 +43,21 @@ struct io {
 static struct kmem_cache *_dm_io_cache;
 
 /*
- * io contexts are only dynamically allocated for asynchronous
- * io.  Since async io is likely to be the majority of io we'll
- * have the same number of io contexts as bios! (FIXME: must reduce this).
- */
-
-static unsigned int pages_to_ios(unsigned int pages)
-{
-        return 4 * pages;       /* too many ? */
-}
-
-/*
  * Create a client with mempool and bioset.
  */
-struct dm_io_client *dm_io_client_create(unsigned num_pages)
+struct dm_io_client *dm_io_client_create(void)
 {
-        unsigned ios = pages_to_ios(num_pages);
         struct dm_io_client *client;
 
         client = kmalloc(sizeof(*client), GFP_KERNEL);
         if (!client)
                 return ERR_PTR(-ENOMEM);
 
-        client->pool = mempool_create_slab_pool(ios, _dm_io_cache);
+        client->pool = mempool_create_slab_pool(MIN_IOS, _dm_io_cache);
         if (!client->pool)
                 goto bad;
 
-        client->bios = bioset_create(16, 0);
+        client->bios = bioset_create(MIN_BIOS, 0);
         if (!client->bios)
                 goto bad;
 
@@ -81,13 +71,6 @@ struct dm_io_client *dm_io_client_create(unsigned num_pages)
 }
 EXPORT_SYMBOL(dm_io_client_create);
 
-int dm_io_client_resize(unsigned num_pages, struct dm_io_client *client)
-{
-        return mempool_resize(client->pool, pages_to_ios(num_pages),
-                              GFP_KERNEL);
-}
-EXPORT_SYMBOL(dm_io_client_resize);
-
 void dm_io_client_destroy(struct dm_io_client *client)
 {
         mempool_destroy(client->pool);
diff --git a/drivers/md/dm-kcopyd.c b/drivers/md/dm-kcopyd.c
index 1bb73a13ca4..819e37eaaeb 100644
--- a/drivers/md/dm-kcopyd.c
+++ b/drivers/md/dm-kcopyd.c
@@ -27,15 +27,19 @@
 
 #include "dm.h"
 
+#define SUB_JOB_SIZE    128
+#define SPLIT_COUNT     8
+#define MIN_JOBS        8
+#define RESERVE_PAGES   (DIV_ROUND_UP(SUB_JOB_SIZE << SECTOR_SHIFT, PAGE_SIZE))
+
 /*-----------------------------------------------------------------
  * Each kcopyd client has its own little pool of preallocated
  * pages for kcopyd io.
  *---------------------------------------------------------------*/
 struct dm_kcopyd_client {
-        spinlock_t lock;
         struct page_list *pages;
-        unsigned int nr_pages;
-        unsigned int nr_free_pages;
+        unsigned nr_reserved_pages;
+        unsigned nr_free_pages;
 
         struct dm_io_client *io_client;
 
@@ -67,15 +71,18 @@ static void wake(struct dm_kcopyd_client *kc)
         queue_work(kc->kcopyd_wq, &kc->kcopyd_work);
 }
 
-static struct page_list *alloc_pl(void)
+/*
+ * Obtain one page for the use of kcopyd.
+ */
+static struct page_list *alloc_pl(gfp_t gfp)
 {
         struct page_list *pl;
 
-        pl = kmalloc(sizeof(*pl), GFP_KERNEL);
+        pl = kmalloc(sizeof(*pl), gfp);
         if (!pl)
                 return NULL;
 
-        pl->page = alloc_page(GFP_KERNEL);
+        pl->page = alloc_page(gfp);
         if (!pl->page) {
                 kfree(pl);
                 return NULL;
@@ -90,41 +97,56 @@ static void free_pl(struct page_list *pl)
         kfree(pl);
 }
 
-static int kcopyd_get_pages(struct dm_kcopyd_client *kc,
-                            unsigned int nr, struct page_list **pages)
+/*
+ * Add the provided pages to a client's free page list, releasing
+ * back to the system any beyond the reserved_pages limit.
+ */
+static void kcopyd_put_pages(struct dm_kcopyd_client *kc, struct page_list *pl)
 {
-        struct page_list *pl;
-
-        spin_lock(&kc->lock);
-        if (kc->nr_free_pages < nr) {
-                spin_unlock(&kc->lock);
-                return -ENOMEM;
-        }
-
-        kc->nr_free_pages -= nr;
-        for (*pages = pl = kc->pages; --nr; pl = pl->next)
-                ;
+        struct page_list *next;
 
-        kc->pages = pl->next;
-        pl->next = NULL;
+        do {
+                next = pl->next;
 
-        spin_unlock(&kc->lock);
+                if (kc->nr_free_pages >= kc->nr_reserved_pages)
+                        free_pl(pl);
+                else {
+                        pl->next = kc->pages;
+                        kc->pages = pl;
+                        kc->nr_free_pages++;
+                }
 
-        return 0;
+                pl = next;
+        } while (pl);
 }
 
-static void kcopyd_put_pages(struct dm_kcopyd_client *kc, struct page_list *pl)
+static int kcopyd_get_pages(struct dm_kcopyd_client *kc,
+                            unsigned int nr, struct page_list **pages)
 {
-        struct page_list *cursor;
+        struct page_list *pl;
+
+        *pages = NULL;
+
+        do {
+                pl = alloc_pl(__GFP_NOWARN | __GFP_NORETRY);
+                if (unlikely(!pl)) {
+                        /* Use reserved pages */
+                        pl = kc->pages;
+                        if (unlikely(!pl))
+                                goto out_of_memory;
+                        kc->pages = pl->next;
+                        kc->nr_free_pages--;
+                }
+                pl->next = *pages;
+                *pages = pl;
+        } while (--nr);
 
-        spin_lock(&kc->lock);
-        for (cursor = pl; cursor->next; cursor = cursor->next)
+        return 0;