nfs: use kmap/kunmap directly

This patch removes useless nfs_readdir_get_array() and
nfs_readdir_release_array() as suggested by Trond Myklebust

nfs_readdir() calls nfs_revalidate_mapping() before
readdir_search_pagecache() , nfs_do_filldir(), uncached_readdir()
so mapping should be correct.

While kmap() can't fail, all subsequent error checks were removed
as well as unused labels.

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 3a188cb5ebce696e22dc7951e75c0895833749a7..32ccd7754f8a2875933d1f9c532b54c656971bfd 100644 (file)
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -169,27 +169,6 @@ typedef struct {
        unsigned int    eof:1;
 } nfs_readdir_descriptor_t;
 
-/*
- * The caller is responsible for calling nfs_readdir_release_array(page)
- */
-static
-struct nfs_cache_array *nfs_readdir_get_array(struct page *page)
-{
-       void *ptr;
-       if (page == NULL)
-               return ERR_PTR(-EIO);
-       ptr = kmap(page);
-       if (ptr == NULL)
-               return ERR_PTR(-ENOMEM);
-       return ptr;
-}
-
-static
-void nfs_readdir_release_array(struct page *page)
-{
-       kunmap(page);
-}
-
 /*
  * we are freeing strings created by nfs_add_to_readdir_array()
  */
@@ -229,13 +208,10 @@ int nfs_readdir_make_qstr(struct qstr *string, const char *name, unsigned int le
 static
 int nfs_readdir_add_to_array(struct nfs_entry *entry, struct page *page)
 {
-       struct nfs_cache_array *array = nfs_readdir_get_array(page);
+       struct nfs_cache_array *array = kmap(page);
        struct nfs_cache_array_entry *cache_entry;
        int ret;
 
-       if (IS_ERR(array))
-               return PTR_ERR(array);
-
        cache_entry = &array->array[array->size];
 
        /* Check that this entry lies within the page bounds */
@@ -254,7 +230,7 @@ int nfs_readdir_add_to_array(struct nfs_entry *entry, struct page *page)
        if (entry->eof != 0)
                array->eof_index = array->size;
 out:
-       nfs_readdir_release_array(page);
+       kunmap(page);
        return ret;
 }
 
@@ -343,11 +319,7 @@ int nfs_readdir_search_array(nfs_readdir_descriptor_t *desc)
        struct nfs_cache_array *array;
        int status;
 
-       array = nfs_readdir_get_array(desc->page);
-       if (IS_ERR(array)) {
-               status = PTR_ERR(array);
-               goto out;
-       }
+       array = kmap(desc->page);
 
        if (*desc->dir_cookie == 0)
                status = nfs_readdir_search_for_pos(array, desc);
@@ -359,8 +331,7 @@ int nfs_readdir_search_array(nfs_readdir_descriptor_t *desc)
                desc->current_index += array->size;
                desc->page_index++;
        }
-       nfs_readdir_release_array(desc->page);
-out:
+       kunmap(desc->page);
        return status;
 }
 
@@ -596,13 +567,10 @@ int nfs_readdir_page_filler(nfs_readdir_descriptor_t *desc, struct nfs_entry *en
 
 out_nopages:
        if (count == 0 || (status == -EBADCOOKIE && entry->eof != 0)) {
-               array = nfs_readdir_get_array(page);
-               if (!IS_ERR(array)) {
-                       array->eof_index = array->size;
-                       status = 0;
-                       nfs_readdir_release_array(page);
-               } else
-                       status = PTR_ERR(array);
+               array = kmap(page);
+               array->eof_index = array->size;
+               status = 0;
+               kunmap(page);
        }
 
        put_page(scratch);
@@ -664,11 +632,7 @@ int nfs_readdir_xdr_to_array(nfs_readdir_descriptor_t *desc, struct page *page,
                goto out;
        }
 
-       array = nfs_readdir_get_array(page);
-       if (IS_ERR(array)) {
-               status = PTR_ERR(array);
-               goto out_label_free;
-       }
+       array = kmap(page);
        memset(array, 0, sizeof(struct nfs_cache_array));
        array->eof_index = -1;
 
@@ -692,8 +656,7 @@ int nfs_readdir_xdr_to_array(nfs_readdir_descriptor_t *desc, struct page *page,
 
        nfs_readdir_free_pages(pages, array_size);
 out_release_array:
-       nfs_readdir_release_array(page);
-out_label_free:
+       kunmap(page);
        nfs4_label_free(entry.label);
 out:
        nfs_free_fattr(entry.fattr);
@@ -791,12 +754,7 @@ int nfs_do_filldir(nfs_readdir_descriptor_t *desc)
        struct nfs_cache_array *array = NULL;
        struct nfs_open_dir_context *ctx = file->private_data;
 
-       array = nfs_readdir_get_array(desc->page);
-       if (IS_ERR(array)) {
-               res = PTR_ERR(array);
-               goto out;
-       }
-
+       array = kmap(desc->page);
        for (i = desc->cache_entry_index; i < array->size; i++) {
                struct nfs_cache_array_entry *ent;
 
@@ -817,8 +775,7 @@ int nfs_do_filldir(nfs_readdir_descriptor_t *desc)
        if (array->eof_index >= 0)
                desc->eof = 1;
 
-       nfs_readdir_release_array(desc->page);
-out:
+       kunmap(desc->page);
        cache_page_release(desc);
        dfprintk(DIRCACHE, "NFS: nfs_do_filldir() filling ended @ cookie %Lu; returning = %d\n",
                        (unsigned long long)*desc->dir_cookie, res);