nfs: move nfs_pgio_data and remove nfs_rw_header

nfs_rw_header was used to allocate an nfs_pgio_header along with an
nfs_pgio_data, because a _header would need at least one _data.

Now there is only ever one nfs_pgio_data for each nfs_pgio_header -- move
it to nfs_pgio_header and get rid of nfs_rw_header.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Weston Andros Adamson <dros@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

6 files changed, 53 insertions, 95 deletions

diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index 8f98138cbc43..179de67ca907 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -148,8 +148,8 @@ static void nfs_direct_set_hdr_verf(struct nfs_direct_req *dreq,
 {
         struct nfs_writeverf *verfp;
 
-        verfp = nfs_direct_select_verf(dreq, hdr->data->ds_clp,
-                                      hdr->data->ds_idx);
+        verfp = nfs_direct_select_verf(dreq, hdr->data.ds_clp,
+                                      hdr->data.ds_idx);
         WARN_ON_ONCE(verfp->committed >= 0);
         memcpy(verfp, &hdr->verf, sizeof(struct nfs_writeverf));
         WARN_ON_ONCE(verfp->committed < 0);
@@ -169,8 +169,8 @@ static int nfs_direct_set_or_cmp_hdr_verf(struct nfs_direct_req *dreq,
 {
         struct nfs_writeverf *verfp;
 
-        verfp = nfs_direct_select_verf(dreq, hdr->data->ds_clp,
-                                         hdr->data->ds_idx);
+        verfp = nfs_direct_select_verf(dreq, hdr->data.ds_clp,
+                                         hdr->data.ds_idx);
         if (verfp->committed < 0) {
                 nfs_direct_set_hdr_verf(dreq, hdr);
                 return 0;
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 82ddbf46660e..5cda049c8f9b 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -238,9 +238,9 @@ void nfs_set_pgio_error(struct nfs_pgio_header *hdr, int error, loff_t pos);
 int nfs_iocounter_wait(struct nfs_io_counter *c);
 
 extern const struct nfs_pageio_ops nfs_pgio_rw_ops;
-struct nfs_rw_header *nfs_rw_header_alloc(const struct nfs_rw_ops *);
-void nfs_rw_header_free(struct nfs_pgio_header *);
-void nfs_pgio_data_release(struct nfs_pgio_data *);
+struct nfs_pgio_header *nfs_pgio_header_alloc(const struct nfs_rw_ops *);
+void nfs_pgio_header_free(struct nfs_pgio_header *);
+void nfs_pgio_data_destroy(struct nfs_pgio_data *);
 int nfs_generic_pgio(struct nfs_pageio_descriptor *, struct nfs_pgio_header *);
 int nfs_initiate_pgio(struct rpc_clnt *, struct nfs_pgio_data *,
                       const struct rpc_call_ops *, int, int);
diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index b6ee3a6ee96d..e4cde476562f 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -452,95 +452,61 @@ size_t nfs_generic_pg_test(struct nfs_pageio_descriptor *desc,
 }
 EXPORT_SYMBOL_GPL(nfs_generic_pg_test);
 
-static inline struct nfs_rw_header *NFS_RW_HEADER(struct nfs_pgio_header *hdr)
+struct nfs_pgio_header *nfs_pgio_header_alloc(const struct nfs_rw_ops *ops)
 {
-        return container_of(hdr, struct nfs_rw_header, header);
-}
-
-/**
- * nfs_rw_header_alloc - Allocate a header for a read or write
- * @ops: Read or write function vector
- */
-struct nfs_rw_header *nfs_rw_header_alloc(const struct nfs_rw_ops *ops)
-{
-        struct nfs_rw_header *header = ops->rw_alloc_header();
-
-        if (header) {
-                struct nfs_pgio_header *hdr = &header->header;
+        struct nfs_pgio_header *hdr = ops->rw_alloc_header();
 
+        if (hdr) {
                 INIT_LIST_HEAD(&hdr->pages);
                 spin_lock_init(&hdr->lock);
                 atomic_set(&hdr->refcnt, 0);
                 hdr->rw_ops = ops;
         }
-        return header;
+        return hdr;
 }
-EXPORT_SYMBOL_GPL(nfs_rw_header_alloc);
+EXPORT_SYMBOL_GPL(nfs_pgio_header_alloc);
 
 /*
- * nfs_rw_header_free - Free a read or write header
+ * nfs_pgio_header_free - Free a read or write header
  * @hdr: The header to free
  */
-void nfs_rw_header_free(struct nfs_pgio_header *hdr)
+void nfs_pgio_header_free(struct nfs_pgio_header *hdr)
 {
-        hdr->rw_ops->rw_free_header(NFS_RW_HEADER(hdr));
+        hdr->rw_ops->rw_free_header(hdr);
 }
-EXPORT_SYMBOL_GPL(nfs_rw_header_free);
+EXPORT_SYMBOL_GPL(nfs_pgio_header_free);
 
 /**
  * nfs_pgio_data_alloc - Allocate pageio data
  * @hdr: The header making a request
  * @pagecount: Number of pages to create
  */
-static struct nfs_pgio_data *nfs_pgio_data_alloc(struct nfs_pgio_header *hdr,
-                                                 unsigned int pagecount)
+static bool nfs_pgio_data_init(struct nfs_pgio_header *hdr,
+                               unsigned int pagecount)
 {
-        struct nfs_pgio_data *data, *prealloc;
-
-        prealloc = &NFS_RW_HEADER(hdr)->rpc_data;
-        if (prealloc->header == NULL)
-                data = prealloc;
-        else
-                data = kzalloc(sizeof(*data), GFP_KERNEL);
-        if (!data)
-                goto out;
-
-        if (nfs_pgarray_set(&data->pages, pagecount)) {
-                data->header = hdr;
+        if (nfs_pgarray_set(&hdr->data.pages, pagecount)) {
+                hdr->data.header = hdr;
                 atomic_inc(&hdr->refcnt);
-        } else {
-                if (data != prealloc)
-                        kfree(data);
-                data = NULL;
+                return true;
         }
-out:
-        return data;
+        return false;
 }
 
 /**
- * nfs_pgio_data_release - Properly free pageio data
- * @data: The data to release
+ * nfs_pgio_data_destroy - Properly free pageio data
+ * @data: The data to destroy
  */
-void nfs_pgio_data_release(struct nfs_pgio_data *data)
+void nfs_pgio_data_destroy(struct nfs_pgio_data *data)
 {
         struct nfs_pgio_header *hdr = data->header;
-        struct nfs_rw_header *pageio_header = NFS_RW_HEADER(hdr);
 
         put_nfs_open_context(data->args.context);
         if (data->pages.pagevec != data->pages.page_array)
                 kfree(data->pages.pagevec);
-        if (data == &pageio_header->rpc_data) {
-                data->header = NULL;
-                data = NULL;
-        }
         if (atomic_dec_and_test(&hdr->refcnt))
                 hdr->completion_ops->completion(hdr);
-        /* Note: we only free the rpc_task after callbacks are done.
-         * See the comment in rpc_free_task() for why
-         */
-        kfree(data);
 }
-EXPORT_SYMBOL_GPL(nfs_pgio_data_release);
+EXPORT_SYMBOL_GPL(nfs_pgio_data_destroy);
 
 /**
  * nfs_pgio_rpcsetup - Set up arguments for a pageio call
@@ -655,8 +621,7 @@ static int nfs_pgio_error(struct nfs_pageio_descriptor *desc,
                           struct nfs_pgio_header *hdr)
 {
         set_bit(NFS_IOHDR_REDO, &hdr->flags);
-        nfs_pgio_data_release(hdr->data);
-        hdr->data = NULL;
+        nfs_pgio_data_destroy(&hdr->data);
         desc->pg_completion_ops->error_cleanup(&desc->pg_list);
         return -ENOMEM;
 }
@@ -670,7 +635,7 @@ static void nfs_pgio_release(void *calldata)
         struct nfs_pgio_data *data = calldata;
         if (data->header->rw_ops->rw_release)
                 data->header->rw_ops->rw_release(data);
-        nfs_pgio_data_release(data);
+        nfs_pgio_data_destroy(data);
 }
 
 /**
@@ -746,11 +711,11 @@ int nfs_generic_pgio(struct nfs_pageio_descriptor *desc,
         struct list_head *head = &desc->pg_list;
         struct nfs_commit_info cinfo;
 
-        data = nfs_pgio_data_alloc(hdr, nfs_page_array_len(desc->pg_base,
-                                                           desc->pg_count));
-        if (!data)
+        if (!nfs_pgio_data_init(hdr, nfs_page_array_len(desc->pg_base,
+                           desc->pg_count)))
                 return nfs_pgio_error(desc, hdr);
 
+        data = &hdr->data;
         nfs_init_cinfo(&cinfo, desc->pg_inode, desc->pg_dreq);
         pages = data->pages.pagevec;
         while (!list_empty(head)) {
@@ -766,7 +731,6 @@ int nfs_generic_pgio(struct nfs_pageio_descriptor *desc,
 
         /* Set up the argument struct */
         nfs_pgio_rpcsetup(data, desc->pg_count, 0, desc->pg_ioflags, &cinfo);
-        hdr->data = data;
         desc->pg_rpc_callops = &nfs_pgio_common_ops;
         return 0;
 }
@@ -774,22 +738,20 @@ EXPORT_SYMBOL_GPL(nfs_generic_pgio);
 
 static int nfs_generic_pg_pgios(struct nfs_pageio_descriptor *desc)
 {
-        struct nfs_rw_header *rw_hdr;
         struct nfs_pgio_header *hdr;
         int ret;
 
-        rw_hdr = nfs_rw_header_alloc(desc->pg_rw_ops);
-        if (!rw_hdr) {
+        hdr = nfs_pgio_header_alloc(desc->pg_rw_ops);
+        if (!hdr) {
                 desc->pg_completion_ops->error_cleanup(&desc->pg_list);
                 return -ENOMEM;
         }
-        hdr = &rw_hdr->header;
-        nfs_pgheader_init(desc, hdr, nfs_rw_header_free);
+        nfs_pgheader_init(desc, hdr, nfs_pgio_header_free);
         atomic_inc(&hdr->refcnt);
         ret = nfs_generic_pgio(desc, hdr);
         if (ret == 0)
                 ret = nfs_initiate_pgio(NFS_CLIENT(hdr->inode),
-                                        hdr->data, desc->pg_rpc_callops,
+                                        &hdr->data, desc->pg_rpc_callops,
                                         desc->pg_ioflags, 0);
         if (atomic_dec_and_test(&hdr->refcnt))
                 hdr->completion_ops->completion(hdr);
diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index 6fdcd233d6f7..067104cce181 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -1546,7 +1546,7 @@ pnfs_write_through_mds(struct nfs_pageio_descriptor *desc,
                 nfs_pageio_reset_write_mds(desc);
                 desc->pg_recoalesce = 1;
         }
-        nfs_pgio_data_release(data);
+        nfs_pgio_data_destroy(data);
 }
 
 static enum pnfs_try_status
@@ -1575,7 +1575,7 @@ static void
 pnfs_do_write(struct nfs_pageio_descriptor *desc,
               struct nfs_pgio_header *hdr, int how)
 {
-        struct nfs_pgio_data *data = hdr->data;
+        struct nfs_pgio_data *data = &hdr->data;
         const struct rpc_call_ops *call_ops = desc->pg_rpc_callops;
         struct pnfs_layout_segment *lseg = desc->pg_lseg;
         enum pnfs_try_status trypnfs;
@@ -1590,25 +1590,23 @@ pnfs_do_write(struct nfs_pageio_descriptor *desc,
 static void pnfs_writehdr_free(struct nfs_pgio_header *hdr)
 {
         pnfs_put_lseg(hdr->lseg);
-        nfs_rw_header_free(hdr);
+        nfs_pgio_header_free(hdr);
 }
 EXPORT_SYMBOL_GPL(pnfs_writehdr_free);
 
 int
 pnfs_generic_pg_writepages(struct nfs_pageio_descriptor *desc)
 {
-        struct nfs_rw_header *whdr;
         struct nfs_pgio_header *hdr;
         int ret;
 
-        whdr = nfs_rw_header_alloc(desc->pg_rw_ops);
-        if (!whdr) {
+        hdr = nfs_pgio_header_alloc(desc->pg_rw_ops);
+        if (!hdr) {
                 desc->pg_completion_ops->error_cleanup(&desc->pg_list);
                 pnfs_put_lseg(desc->pg_lseg);
                 desc->pg_lseg = NULL;
                 return -ENOMEM;
         }
-        hdr = &whdr->header;
         nfs_pgheader_init(desc, hdr, pnfs_writehdr_free);
         hdr->lseg = pnfs_get_lseg(desc->pg_lseg);
         atomic_inc(&hdr->refcnt);
@@ -1696,7 +1694,7 @@ pnfs_read_through_mds(struct nfs_pageio_descriptor *desc,
                 nfs_pageio_reset_read_mds(desc);
                 desc->pg_recoalesce = 1;
         }
-        nfs_pgio_data_release(data);
+        nfs_pgio_data_destroy(data);
 }
 
 /*
@@ -1727,7 +1725,7 @@ pnfs_try_to_read_data(struct nfs_pgio_data *rdata,
 static void
 pnfs_do_read(struct nfs_pageio_descriptor *desc, struct nfs_pgio_header *hdr)
 {
-        struct nfs_pgio_data *data = hdr->data;
+        struct nfs_pgio_data *data = &hdr->data;
         const struct rpc_call_ops *call_ops = desc->pg_rpc_callops;
         struct pnfs_layout_segment *lseg = desc->pg_lseg;
         enum pnfs_try_status trypnfs;
@@ -1742,26 +1740,24 @@ pnfs_do_read(struct nfs_pageio_descriptor *desc, struct nfs_pgio_header *hdr)
 static void pnfs_readhdr_free(struct nfs_pgio_header *hdr)
 {
         pnfs_put_lseg(hdr->lseg);
-        nfs_rw_header_free(hdr);
+        nfs_pgio_header_free(hdr);
 }
 EXPORT_SYMBOL_GPL(pnfs_readhdr_free);
 
 int
 pnfs_generic_pg_readpages(struct nfs_pageio_descriptor *desc)
 {
-        struct nfs_rw_header *rhdr;
         struct nfs_pgio_header *hdr;
         int ret;
 
-        rhdr = nfs_rw_header_alloc(desc->pg_rw_ops);
-        if (!rhdr) {
+        hdr = nfs_pgio_header_alloc(desc->pg_rw_ops);
+        if (!hdr) {
                 desc->pg_completion_ops->error_cleanup(&desc->pg_list);
                 ret = -ENOMEM;
                 pnfs_put_lseg(desc->pg_lseg);
                 desc->pg_lseg = NULL;
                 return ret;
         }
-        hdr = &rhdr->header;
         nfs_pgheader_init(desc, hdr, pnfs_readhdr_free);
         hdr->lseg = pnfs_get_lseg(desc->pg_lseg);
         atomic_inc(&hdr->refcnt);
diff --git a/fs/nfs/read.c b/fs/nfs/read.c
index e818a475ca64..d9df4ab3737b 100644
--- a/fs/nfs/read.c
+++ b/fs/nfs/read.c
@@ -33,12 +33,12 @@ static const struct nfs_rw_ops nfs_rw_read_ops;
 
 static struct kmem_cache *nfs_rdata_cachep;
 
-static struct nfs_rw_header *nfs_readhdr_alloc(void)
+static struct nfs_pgio_header *nfs_readhdr_alloc(void)
 {
         return kmem_cache_zalloc(nfs_rdata_cachep, GFP_KERNEL);
 }
 
-static void nfs_readhdr_free(struct nfs_rw_header *rhdr)
+static void nfs_readhdr_free(struct nfs_pgio_header *rhdr)
 {
         kmem_cache_free(nfs_rdata_cachep, rhdr);
 }
@@ -404,7 +404,7 @@ out:
 int __init nfs_init_readpagecache(void)
 {
         nfs_rdata_cachep = kmem_cache_create("nfs_read_data",
-                                             sizeof(struct nfs_rw_header),
+                                             sizeof(struct nfs_pgio_header),
                                              0, SLAB_HWCACHE_ALIGN,
                                              NULL);
         if (nfs_rdata_cachep == NULL)
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 98ff061ccaf3..d694952f0071 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -70,18 +70,18 @@ void nfs_commit_free(struct nfs_commit_data *p)
 }
 EXPORT_SYMBOL_GPL(nfs_commit_free);
 
-static struct nfs_rw_header *nfs_writehdr_alloc(void)
+static struct nfs_pgio_header *nfs_writehdr_alloc(void)
 {
-        struct nfs_rw_header *p = mempool_alloc(nfs_wdata_mempool, GFP_NOIO);
+        struct nfs_pgio_header *p = mempool_alloc(nfs_wdata_mempool, GFP_NOIO);
 
         if (p)
                 memset(p, 0, sizeof(*p));
         return p;
 }
 
-static void nfs_writehdr_free(struct nfs_rw_header *whdr)
+static void nfs_writehdr_free(struct nfs_pgio_header *hdr)
 {
-        mempool_free(whdr, nfs_wdata_mempool);
+        mempool_free(hdr, nfs_wdata_mempool);
 }
 
 static void nfs_context_set_write_error(struct nfs_open_context *ctx, int error)
@@ -1655,7 +1655,7 @@ int nfs_migrate_page(struct address_space *mapping, struct page *newpage,
 int __init nfs_init_writepagecache(void)
 {
         nfs_wdata_cachep = kmem_cache_create("nfs_write_data",
-                                             sizeof(struct nfs_rw_header),
+                                             sizeof(struct nfs_pgio_header),
                                              0, SLAB_HWCACHE_ALIGN,
                                              NULL);
         if (nfs_wdata_cachep == NULL)