[PATCH 11/16] erofs: get rid of `z_pagemap_global'

[Gao Xiang]

In order to introduce multi-reference pclusters for compressed data
deduplication, let's get rid of the global page array for now since
it needs to be re-designed then at least.

Signed-off-by: Gao Xiang <hsiang...@linux.alibaba.com>
---
 fs/erofs/zdata.c | 28 ++++------------------------
 fs/erofs/zdata.h |  1 -
 2 files changed, 4 insertions(+), 25 deletions(-)

diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
index 55bcd6e5ae9a..f24b866bc975 100644
--- a/fs/erofs/zdata.c
+++ b/fs/erofs/zdata.c
@@ -291,9 +291,6 @@ struct z_erofs_decompress_frontend {
        .inode = __i, .owned_head = Z_EROFS_PCLUSTER_TAIL, \
        .mode = Z_EROFS_PCLUSTER_FOLLOWED, .backmost = true }
 
-static struct page *z_pagemap_global[Z_EROFS_VMAP_GLOBAL_PAGES];
-static DEFINE_MUTEX(z_pagemap_global_lock);
-
 static void z_erofs_bind_cache(struct z_erofs_decompress_frontend *fe,
                               enum z_erofs_cache_alloctype type,
                               struct page **pagepool)
@@ -966,26 +963,11 @@ static int z_erofs_decompress_pcluster(struct super_block 
*sb,
        mutex_lock(&pcl->lock);
        nr_pages = pcl->nr_pages;
 
-       if (nr_pages <= Z_EROFS_VMAP_ONSTACK_PAGES) {
+       if (nr_pages <= Z_EROFS_VMAP_ONSTACK_PAGES)
                pages = pages_onstack;
-       } else if (nr_pages <= Z_EROFS_VMAP_GLOBAL_PAGES &&
-                  mutex_trylock(&z_pagemap_global_lock)) {
-               pages = z_pagemap_global;
-       } else {
-               gfp_t gfp_flags = GFP_KERNEL;
-
-               if (nr_pages > Z_EROFS_VMAP_GLOBAL_PAGES)
-                       gfp_flags |= __GFP_NOFAIL;
-
+       else
                pages = kvmalloc_array(nr_pages, sizeof(struct page *),
-                                      gfp_flags);
-
-               /* fallback to global pagemap for the lowmem scenario */
-               if (!pages) {
-                       mutex_lock(&z_pagemap_global_lock);
-                       pages = z_pagemap_global;
-               }
-       }
+                                      GFP_KERNEL | __GFP_NOFAIL);
 
        for (i = 0; i < nr_pages; ++i)
                pages[i] = NULL;
@@ -1063,9 +1045,7 @@ static int z_erofs_decompress_pcluster(struct super_block 
*sb,
                z_erofs_onlinepage_endio(page);
        }
 
-       if (pages == z_pagemap_global)
-               mutex_unlock(&z_pagemap_global_lock);
-       else if (pages != pages_onstack)
+       if (pages != pages_onstack)
                kvfree(pages);
 
        pcl->nr_pages = 0;
diff --git a/fs/erofs/zdata.h b/fs/erofs/zdata.h
index 852da31e2e91..5964c942799e 100644
--- a/fs/erofs/zdata.h
+++ b/fs/erofs/zdata.h
@@ -175,6 +175,5 @@ static inline void z_erofs_onlinepage_endio(struct page 
*page)
 
 #define Z_EROFS_VMAP_ONSTACK_PAGES     \
        min_t(unsigned int, THREAD_SIZE / 8 / sizeof(struct page *), 96U)
-#define Z_EROFS_VMAP_GLOBAL_PAGES      2048
 
 #endif
-- 
2.24.4