erofs: clean up collection handling routines

 - change return value to int since collection is
   already returned within the collector.
 - better function naming.

Link: https://lore.kernel.org/r/20191008125616.183715-1-gaoxiang25@huawei.com
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>

diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
index fad80c9..ef32757 100644 (file)
--- a/fs/erofs/zdata.c
+++ b/fs/erofs/zdata.c
@@ -337,9 +337,9 @@ retry:
        return COLLECT_PRIMARY; /* :( better luck next time */
 }
 
-static struct z_erofs_collection *cllookup(struct z_erofs_collector *clt,
-                                          struct inode *inode,
-                                          struct erofs_map_blocks *map)
+static int z_erofs_lookup_collection(struct z_erofs_collector *clt,
+                                    struct inode *inode,
+                                    struct erofs_map_blocks *map)
 {
        struct erofs_workgroup *grp;
        struct z_erofs_pcluster *pcl;
@@ -349,20 +349,20 @@ static struct z_erofs_collection *cllookup(struct z_erofs_collector *clt,
 
        grp = erofs_find_workgroup(inode->i_sb, map->m_pa >> PAGE_SHIFT, &tag);
        if (!grp)
-               return NULL;
+               return -ENOENT;
 
        pcl = container_of(grp, struct z_erofs_pcluster, obj);
        if (clt->owned_head == &pcl->next || pcl == clt->tailpcl) {
                DBG_BUGON(1);
                erofs_workgroup_put(grp);
-               return ERR_PTR(-EFSCORRUPTED);
+               return -EFSCORRUPTED;
        }
 
        cl = z_erofs_primarycollection(pcl);
        if (cl->pageofs != (map->m_la & ~PAGE_MASK)) {
                DBG_BUGON(1);
                erofs_workgroup_put(grp);
-               return ERR_PTR(-EFSCORRUPTED);
+               return -EFSCORRUPTED;
        }
 
        length = READ_ONCE(pcl->length);
@@ -370,7 +370,7 @@ static struct z_erofs_collection *cllookup(struct z_erofs_collector *clt,
                if ((map->m_llen << Z_EROFS_PCLUSTER_LENGTH_BIT) > length) {
                        DBG_BUGON(1);
                        erofs_workgroup_put(grp);
-                       return ERR_PTR(-EFSCORRUPTED);
+                       return -EFSCORRUPTED;
                }
        } else {
                unsigned int llen = map->m_llen << Z_EROFS_PCLUSTER_LENGTH_BIT;
@@ -394,12 +394,12 @@ static struct z_erofs_collection *cllookup(struct z_erofs_collector *clt,
                clt->tailpcl = NULL;
        clt->pcl = pcl;
        clt->cl = cl;
-       return cl;
+       return 0;
 }
 
-static struct z_erofs_collection *clregister(struct z_erofs_collector *clt,
-                                            struct inode *inode,
-                                            struct erofs_map_blocks *map)
+static int z_erofs_register_collection(struct z_erofs_collector *clt,
+                                      struct inode *inode,
+                                      struct erofs_map_blocks *map)
 {
        struct z_erofs_pcluster *pcl;
        struct z_erofs_collection *cl;
@@ -408,7 +408,7 @@ static struct z_erofs_collection *clregister(struct z_erofs_collector *clt,
        /* no available workgroup, let's allocate one */
        pcl = kmem_cache_alloc(pcluster_cachep, GFP_NOFS);
        if (!pcl)
-               return ERR_PTR(-ENOMEM);
+               return -ENOMEM;
 
        z_erofs_pcluster_init_always(pcl);
        pcl->obj.index = map->m_pa >> PAGE_SHIFT;
@@ -442,7 +442,7 @@ static struct z_erofs_collection *clregister(struct z_erofs_collector *clt,
        if (err) {
                mutex_unlock(&cl->lock);
                kmem_cache_free(pcluster_cachep, pcl);
-               return ERR_PTR(-EAGAIN);
+               return -EAGAIN;
        }
        /* used to check tail merging loop due to corrupted images */
        if (clt->owned_head == Z_EROFS_PCLUSTER_TAIL)
@@ -450,14 +450,14 @@ static struct z_erofs_collection *clregister(struct z_erofs_collector *clt,
        clt->owned_head = &pcl->next;
        clt->pcl = pcl;
        clt->cl = cl;
-       return cl;
+       return 0;
 }
 
 static int z_erofs_collector_begin(struct z_erofs_collector *clt,
                                   struct inode *inode,
                                   struct erofs_map_blocks *map)
 {
-       struct z_erofs_collection *cl;
+       int ret;
 
        DBG_BUGON(clt->cl);
 
@@ -471,19 +471,22 @@ static int z_erofs_collector_begin(struct z_erofs_collector *clt,
        }
 
 repeat:
-       cl = cllookup(clt, inode, map);
-       if (!cl) {
-               cl = clregister(clt, inode, map);
+       ret = z_erofs_lookup_collection(clt, inode, map);
+       if (ret == -ENOENT) {
+               ret = z_erofs_register_collection(clt, inode, map);
 
-               if (cl == ERR_PTR(-EAGAIN))
+               /* someone registered at the same time, give another try */
+               if (ret == -EAGAIN) {
+                       cond_resched();
                        goto repeat;
+               }
        }
 
-       if (IS_ERR(cl))
-               return PTR_ERR(cl);
+       if (ret)
+               return ret;
 
        z_erofs_pagevec_ctor_init(&clt->vector, Z_EROFS_NR_INLINE_PAGEVECS,
-                                 cl->pagevec, cl->vcnt);
+                                 clt->cl->pagevec, clt->cl->vcnt);
 
        clt->compressedpages = clt->pcl->compressed_pages;
        if (clt->mode <= COLLECT_PRIMARY) /* cannot do in-place I/O */