[PATCH for-4.19 04/12] staging: erofs: drop multiref support temporarily

20 Feb 2019

commit e5e3abbadf0dbd1068f64f8abe70401c5a178180 upstream.
Multiref support means that a compressed page could have
more than one reference, which is designed for on-disk data
deduplication. However, mkfs doesn't support this mode
at this moment, and the kernel implementation is also broken.
Let's drop multiref support. If it is fully implemented
in the future, it can be reverted later.
Signed-off-by: Gao Xiang gaoxiang25@huawei.com
Reviewed-by: Chao Yu yuchao0@huawei.com
Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
Conflicts:
    drivers/staging/erofs/unzip_vle.c
Signed-off-by: Gao Xiang gaoxiang25@huawei.com
---
 drivers/staging/erofs/unzip_vle.c | 40 +++++++--------------------------------
 drivers/staging/erofs/unzip_vle.h | 12 +-----------
 2 files changed, 8 insertions(+), 44 deletions(-)

diff --git a/drivers/staging/erofs/unzip_vle.c b/drivers/staging/erofs/unzip_vle.c
index 9ae1f8833b72..63accc4527ce 100644
--- a/drivers/staging/erofs/unzip_vle.c
+++ b/drivers/staging/erofs/unzip_vle.c
@@ -293,12 +293,9 @@ z_erofs_vle_work_lookup(struct super_block *sb,
    *grp_ret = grp = container_of(egrp,
    	struct z_erofs_vle_workgroup, obj);
-#ifndef CONFIG_EROFS_FS_ZIP_MULTIREF
    work = z_erofs_vle_grab_work(grp, pageofs);
+	/* if multiref is disabled, `primary' is always true */
    primary = true;
-#else
-	BUG();
-#endif
DBG_BUGON(work->pageofs != pageofs);
@@ -365,12 +362,9 @@ z_erofs_vle_work_register(struct super_block *sb,
    struct z_erofs_vle_workgroup *grp = *grp_ret;
    struct z_erofs_vle_work *work;
-#ifndef CONFIG_EROFS_FS_ZIP_MULTIREF
+	/* if multiref is disabled, grp should never be nullptr */
    BUG_ON(grp != NULL);
-#else
-	if (grp != NULL)
-		goto skip;
-#endif
+
    /* no available workgroup, let's allocate one */
    grp = kmem_cache_zalloc(z_erofs_workgroup_cachep, GFP_NOFS);
    if (unlikely(grp == NULL))
@@ -393,13 +387,7 @@ z_erofs_vle_work_register(struct super_block *sb,
    *hosted = true;
newgrp = true;
-#ifdef CONFIG_EROFS_FS_ZIP_MULTIREF
-skip:
-	/* currently unimplemented */
-	BUG();
-#else
    work = z_erofs_vle_grab_primary_work(grp);
-#endif
    work->pageofs = pageofs;
mutex_init(&work->lock);
@@ -798,10 +786,8 @@ static int z_erofs_vle_unzip(struct super_block *sb,
    const unsigned clusterpages = erofs_clusterpages(sbi);
struct z_erofs_pagevec_ctor ctor;
-	unsigned nr_pages;
-#ifndef CONFIG_EROFS_FS_ZIP_MULTIREF
-	unsigned sparsemem_pages = 0;
-#endif
+	unsigned int nr_pages;
+	unsigned int sparsemem_pages = 0;
    struct page *pages_onstack[Z_EROFS_VLE_VMAP_ONSTACK_PAGES];
    struct page **pages, **compressed_pages, *page;
    unsigned i, llen;
@@ -813,11 +799,7 @@ static int z_erofs_vle_unzip(struct super_block *sb,
    int err;
might_sleep();
-#ifndef CONFIG_EROFS_FS_ZIP_MULTIREF
    work = z_erofs_vle_grab_primary_work(grp);
-#else
-	BUG();
-#endif
    BUG_ON(!READ_ONCE(work->nr_pages));
mutex_lock(&work->lock);
@@ -868,13 +850,11 @@ static int z_erofs_vle_unzip(struct super_block *sb,
    		pagenr = z_erofs_onlinepage_index(page);
BUG_ON(pagenr >= nr_pages);
-
-#ifndef CONFIG_EROFS_FS_ZIP_MULTIREF
    	BUG_ON(pages[pagenr] != NULL);
-		++sparsemem_pages;
-#endif
+
    	pages[pagenr] = page;
    }
+	sparsemem_pages = i;
z_erofs_pagevec_ctor_exit(&ctor, true);
@@ -904,10 +884,8 @@ static int z_erofs_vle_unzip(struct super_block *sb,
    	pagenr = z_erofs_onlinepage_index(page);
BUG_ON(pagenr >= nr_pages);
-#ifndef CONFIG_EROFS_FS_ZIP_MULTIREF
    	BUG_ON(pages[pagenr] != NULL);
    	++sparsemem_pages;
-#endif
    	pages[pagenr] = page;
overlapped = true;
@@ -933,12 +911,10 @@ static int z_erofs_vle_unzip(struct super_block *sb,
    if (err != -ENOTSUPP)
    	goto out_percpu;
-#ifndef CONFIG_EROFS_FS_ZIP_MULTIREF
    if (sparsemem_pages >= nr_pages) {
    	BUG_ON(sparsemem_pages > nr_pages);
    	goto skip_allocpage;
    }
-#endif
for (i = 0; i < nr_pages; ++i) {
    	if (pages[i] != NULL)
@@ -947,9 +923,7 @@ static int z_erofs_vle_unzip(struct super_block *sb,
    	pages[i] = __stagingpage_alloc(page_pool, GFP_NOFS);
    }
-#ifndef CONFIG_EROFS_FS_ZIP_MULTIREF
 skip_allocpage:
-#endif
    vout = erofs_vmap(pages, nr_pages);
err = z_erofs_vle_unzip_vmap(compressed_pages,
diff --git a/drivers/staging/erofs/unzip_vle.h b/drivers/staging/erofs/unzip_vle.h
index 393998500865..3316bc36965d 100644
--- a/drivers/staging/erofs/unzip_vle.h
+++ b/drivers/staging/erofs/unzip_vle.h
@@ -47,13 +47,6 @@ static inline bool z_erofs_gather_if_stagingpage(struct list_head *page_pool,
 #define Z_EROFS_VLE_INLINE_PAGEVECS     3
struct z_erofs_vle_work {
-	/* struct z_erofs_vle_work *left, *right; */
-
-#ifdef CONFIG_EROFS_FS_ZIP_MULTIREF
-	struct list_head list;
-
-	atomic_t refcount;
-#endif
    struct mutex lock;
/* I: decompression offset in page */
@@ -107,10 +100,8 @@ static inline void z_erofs_vle_set_workgrp_fmt(
    grp->flags = fmt | (grp->flags & ~Z_EROFS_VLE_WORKGRP_FMT_MASK);
 }
-#ifdef CONFIG_EROFS_FS_ZIP_MULTIREF
-#error multiref decompression is unimplemented yet
-#else
+/* definitions if multiref is disabled */
 #define z_erofs_vle_grab_primary_work(grp)	(&(grp)->work)
 #define z_erofs_vle_grab_work(grp, pageofs)	(&(grp)->work)
 #define z_erofs_vle_work_workgroup(wrk, primary)	\
@@ -118,7 +109,6 @@ static inline void z_erofs_vle_set_workgrp_fmt(
    	struct z_erofs_vle_workgroup, work) : \
    	({ BUG(); (void *)NULL; }))
-#endif
#define Z_EROFS_WORKGROUP_SIZE       sizeof(struct z_erofs_vle_workgroup)
-- 
2.14.4


    

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[PATCH for-4.19 04/12] staging: erofs: drop multiref support temporarily