1 files changed, 133 insertions, 99 deletions

diff --git a/drivers/md/dm-io.c b/drivers/md/dm-io.c
index 8bdc8a87b249..352c6fbeac53 100644
--- a/drivers/md/dm-io.c
+++ b/drivers/md/dm-io.c
@@ -1,5 +1,6 @@
 /*
  * Copyright (C) 2003 Sistina Software
+ * Copyright (C) 2006 Red Hat GmbH
  *
  * This file is released under the GPL.
  */
@@ -12,13 +13,17 @@
 #include <linux/sched.h>
 #include <linux/slab.h>
 
-static struct bio_set *_bios;
+struct dm_io_client {
+        mempool_t *pool;
+        struct bio_set *bios;
+};
 
 /* FIXME: can we shrink this ? */
 struct io {
         unsigned long error;
         atomic_t count;
         struct task_struct *sleeper;
+        struct dm_io_client *client;
         io_notify_fn callback;
         void *context;
 };
@@ -26,63 +31,58 @@ struct io {
 /*
  * 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 buffer heads ! (FIXME:
- * must reduce this).
+ * have the same number of io contexts as bios! (FIXME: must reduce this).
  */
-static unsigned _num_ios;
-static mempool_t *_io_pool;
 
 static unsigned int pages_to_ios(unsigned int pages)
 {
         return 4 * pages;       /* too many ? */
 }
 
-static int resize_pool(unsigned int new_ios)
+/*
+ * Create a client with mempool and bioset.
+ */
+struct dm_io_client *dm_io_client_create(unsigned num_pages)
 {
-        int r = 0;
-
-        if (_io_pool) {
-                if (new_ios == 0) {
-                        /* free off the pool */
-                        mempool_destroy(_io_pool);
-                        _io_pool = NULL;
-                        bioset_free(_bios);
-
-                } else {
-                        /* resize the pool */
-                        r = mempool_resize(_io_pool, new_ios, GFP_KERNEL);
-                }
+        unsigned ios = pages_to_ios(num_pages);
+        struct dm_io_client *client;
 
-        } else {
-                /* create new pool */
-                _io_pool = mempool_create_kmalloc_pool(new_ios,
-                                                       sizeof(struct io));
-                if (!_io_pool)
-                        return -ENOMEM;
-
-                _bios = bioset_create(16, 16);
-                if (!_bios) {
-                        mempool_destroy(_io_pool);
-                        _io_pool = NULL;
-                        return -ENOMEM;
-                }
-        }
+        client = kmalloc(sizeof(*client), GFP_KERNEL);
+        if (!client)
+                return ERR_PTR(-ENOMEM);
+
+        client->pool = mempool_create_kmalloc_pool(ios, sizeof(struct io));
+        if (!client->pool)
+                goto bad;
 
-        if (!r)
-                _num_ios = new_ios;
+        client->bios = bioset_create(16, 16);
+        if (!client->bios)
+                goto bad;
 
-        return r;
+        return client;
+
+   bad:
+        if (client->pool)
+                mempool_destroy(client->pool);
+        kfree(client);
+        return ERR_PTR(-ENOMEM);
 }
+EXPORT_SYMBOL(dm_io_client_create);
 
-int dm_io_get(unsigned int num_pages)
+int dm_io_client_resize(unsigned num_pages, struct dm_io_client *client)
 {
-        return resize_pool(_num_ios + pages_to_ios(num_pages));
+        return mempool_resize(client->pool, pages_to_ios(num_pages),
+                              GFP_KERNEL);
 }
+EXPORT_SYMBOL(dm_io_client_resize);
 
-void dm_io_put(unsigned int num_pages)
+void dm_io_client_destroy(struct dm_io_client *client)
 {
-        resize_pool(_num_ios - pages_to_ios(num_pages));
+        mempool_destroy(client->pool);
+        bioset_free(client->bios);
+        kfree(client);
 }
+EXPORT_SYMBOL(dm_io_client_destroy);
 
 /*-----------------------------------------------------------------
  * We need to keep track of which region a bio is doing io for.
@@ -118,7 +118,7 @@ static void dec_count(struct io *io, unsigned int region, int error)
                         io_notify_fn fn = io->callback;
                         void *context = io->context;
 
-                        mempool_free(io, _io_pool);
+                        mempool_free(io, io->client->pool);
                         fn(r, context);
                 }
         }
@@ -126,7 +126,8 @@ static void dec_count(struct io *io, unsigned int region, int error)
 
 static int endio(struct bio *bio, unsigned int done, int error)
 {
-        struct io *io = (struct io *) bio->bi_private;
+        struct io *io;
+        unsigned region;
 
         /* keep going until we've finished */
         if (bio->bi_size)
@@ -135,10 +136,17 @@ static int endio(struct bio *bio, unsigned int done, int error)
         if (error && bio_data_dir(bio) == READ)
                 zero_fill_bio(bio);
 
-        dec_count(io, bio_get_region(bio), error);
+        /*
+         * The bio destructor in bio_put() may use the io object.
+         */
+        io = bio->bi_private;
+        region = bio_get_region(bio);
+
         bio->bi_max_vecs++;
         bio_put(bio);
 
+        dec_count(io, region, error);
+
         return 0;
 }
 
@@ -209,6 +217,9 @@ static void bvec_dp_init(struct dpages *dp, struct bio_vec *bvec)
         dp->context_ptr = bvec;
 }
 
+/*
+ * Functions for getting the pages from a VMA.
+ */
 static void vm_get_page(struct dpages *dp,
                  struct page **p, unsigned long *len, unsigned *offset)
 {
@@ -233,7 +244,34 @@ static void vm_dp_init(struct dpages *dp, void *data)
 
 static void dm_bio_destructor(struct bio *bio)
 {
-        bio_free(bio, _bios);
+        struct io *io = bio->bi_private;
+
+        bio_free(bio, io->client->bios);
+}
+
+/*
+ * Functions for getting the pages from kernel memory.
+ */
+static void km_get_page(struct dpages *dp, struct page **p, unsigned long *len,
+                        unsigned *offset)
+{
+        *p = virt_to_page(dp->context_ptr);
+        *offset = dp->context_u;
+        *len = PAGE_SIZE - dp->context_u;
+}
+
+static void km_next_page(struct dpages *dp)
+{
+        dp->context_ptr += PAGE_SIZE - dp->context_u;
+        dp->context_u = 0;
+}
+
+static void km_dp_init(struct dpages *dp, void *data)
+{
+        dp->get_page = km_get_page;
+        dp->next_page = km_next_page;
+        dp->context_u = ((unsigned long) data) & (PAGE_SIZE - 1);
+        dp->context_ptr = data;
 }
 
 /*-----------------------------------------------------------------
@@ -256,7 +294,7 @@ static void do_region(int rw, unsigned int region, struct io_region *where,
                  * to hide it from bio_add_page().
                  */
                 num_bvecs = (remaining / (PAGE_SIZE >> SECTOR_SHIFT)) + 2;
-                bio = bio_alloc_bioset(GFP_NOIO, num_bvecs, _bios);
+                bio = bio_alloc_bioset(GFP_NOIO, num_bvecs, io->client->bios);
                 bio->bi_sector = where->sector + (where->count - remaining);
                 bio->bi_bdev = where->bdev;
                 bio->bi_end_io = endio;
@@ -311,8 +349,9 @@ static void dispatch_io(int rw, unsigned int num_regions,
         dec_count(io, 0, 0);
 }
 
-static int sync_io(unsigned int num_regions, struct io_region *where,
-            int rw, struct dpages *dp, unsigned long *error_bits)
+static int sync_io(struct dm_io_client *client, unsigned int num_regions,
+                   struct io_region *where, int rw, struct dpages *dp,
+                   unsigned long *error_bits)
 {
         struct io io;
 
@@ -324,6 +363,7 @@ static int sync_io(unsigned int num_regions, struct io_region *where,
         io.error = 0;
         atomic_set(&io.count, 1); /* see dispatch_io() */
         io.sleeper = current;
+        io.client = client;
 
         dispatch_io(rw, num_regions, where, dp, &io, 1);
 
@@ -340,12 +380,15 @@ static int sync_io(unsigned int num_regions, struct io_region *where,
         if (atomic_read(&io.count))
                 return -EINTR;
 
-        *error_bits = io.error;
+        if (error_bits)
+                *error_bits = io.error;
+
         return io.error ? -EIO : 0;
 }
 
-static int async_io(unsigned int num_regions, struct io_region *where, int rw,
-             struct dpages *dp, io_notify_fn fn, void *context)
+static int async_io(struct dm_io_client *client, unsigned int num_regions,
+                    struct io_region *where, int rw, struct dpages *dp,
+                    io_notify_fn fn, void *context)
 {
         struct io *io;
 
@@ -355,10 +398,11 @@ static int async_io(unsigned int num_regions, struct io_region *where, int rw,
                 return -EIO;
         }
 
-        io = mempool_alloc(_io_pool, GFP_NOIO);
+        io = mempool_alloc(client->pool, GFP_NOIO);
         io->error = 0;
         atomic_set(&io->count, 1); /* see dispatch_io() */
         io->sleeper = NULL;
+        io->client = client;
         io->callback = fn;
         io->context = context;
 
@@ -366,61 +410,51 @@ static int async_io(unsigned int num_regions, struct io_region *where, int rw,
         return 0;
 }
 
-int dm_io_sync(unsigned int num_regions, struct io_region *where, int rw,
-               struct page_list *pl, unsigned int offset,
-               unsigned long *error_bits)
+static int dp_init(struct dm_io_request *io_req, struct dpages *dp)
 {
-        struct dpages dp;
-        list_dp_init(&dp, pl, offset);
-        return sync_io(num_regions, where, rw, &dp, error_bits);
-}
+        /* Set up dpages based on memory type */
+        switch (io_req->mem.type) {
+        case DM_IO_PAGE_LIST:
+                list_dp_init(dp, io_req->mem.ptr.pl, io_req->mem.offset);
+                break;
+
+        case DM_IO_BVEC:
+                bvec_dp_init(dp, io_req->mem.ptr.bvec);
+                break;
+
+        case DM_IO_VMA:
+                vm_dp_init(dp, io_req->mem.ptr.vma);
+                break;
+
+        case DM_IO_KMEM:
+                km_dp_init(dp, io_req->mem.ptr.addr);
+                break;
+
+        default:
+                return -EINVAL;
+        }
 
-int dm_io_sync_bvec(unsigned int num_regions, struct io_region *where, int rw,
-                    struct bio_vec *bvec, unsigned long *error_bits)
-{
-        struct dpages dp;
-        bvec_dp_init(&dp, bvec);
-        return sync_io(num_regions, where, rw, &dp, error_bits);
+        return 0;
 }
 
-int dm_io_sync_vm(unsigned int num_regions, struct io_region *where, int rw,
-                  void *data, unsigned long *error_bits)
+/*
+ * New collapsed (a)synchronous interface
+ */
+int dm_io(struct dm_io_request *io_req, unsigned num_regions,
+          struct io_region *where, unsigned long *sync_error_bits)
 {
+        int r;
         struct dpages dp;
-        vm_dp_init(&dp, data);
-        return sync_io(num_regions, where, rw, &dp, error_bits);
-}
 
-int dm_io_async(unsigned int num_regions, struct io_region *where, int rw,
-                struct page_list *pl, unsigned int offset,
-                io_notify_fn fn, void *context)
-{
-        struct dpages dp;
-        list_dp_init(&dp, pl, offset);
-        return async_io(num_regions, where, rw, &dp, fn, context);
-}
+        r = dp_init(io_req, &dp);
+        if (r)
+                return r;
 
-int dm_io_async_bvec(unsigned int num_regions, struct io_region *where, int rw,
-                     struct bio_vec *bvec, io_notify_fn fn, void *context)
-{
-        struct dpages dp;
-        bvec_dp_init(&dp, bvec);
-        return async_io(num_regions, where, rw, &dp, fn, context);
-}
+        if (!io_req->notify.fn)
+                return sync_io(io_req->client, num_regions, where,
+                               io_req->bi_rw, &dp, sync_error_bits);
 
-int dm_io_async_vm(unsigned int num_regions, struct io_region *where, int rw,
-                   void *data, io_notify_fn fn, void *context)
-{
-        struct dpages dp;
-        vm_dp_init(&dp, data);
-        return async_io(num_regions, where, rw, &dp, fn, context);
+        return async_io(io_req->client, num_regions, where, io_req->bi_rw,
+                        &dp, io_req->notify.fn, io_req->notify.context);
 }
-
-EXPORT_SYMBOL(dm_io_get);
-EXPORT_SYMBOL(dm_io_put);
-EXPORT_SYMBOL(dm_io_sync);
-EXPORT_SYMBOL(dm_io_async);
-EXPORT_SYMBOL(dm_io_sync_bvec);
-EXPORT_SYMBOL(dm_io_async_bvec);
-EXPORT_SYMBOL(dm_io_sync_vm);
-EXPORT_SYMBOL(dm_io_async_vm);
+EXPORT_SYMBOL(dm_io);