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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Gao Xiang <gaoxiang25@huawei.com>,
        Chao Yu <yuchao0@huawei.com>
Subject: [PATCH 4.20 175/183] staging: erofs: unzip_{pagevec.h,vle.c}: rectify BUG_ONs
Date:   Mon, 25 Feb 2019 22:12:28 +0100
Message-Id: <20190225195124.646299368@linuxfoundation.org>
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4.20-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Gao Xiang <gaoxiang25@huawei.com>

commit 70b17991d89554cdd16f3e4fb0179bcc03c808d9 upstream.

remove all redundant BUG_ONs, and turn the rest
useful usages to DBG_BUGONs.

Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>


---
 drivers/staging/erofs/unzip_pagevec.h |    2 -
 drivers/staging/erofs/unzip_vle.c     |   35 +++++++++++++---------------------
 2 files changed, 15 insertions(+), 22 deletions(-)

--- a/drivers/staging/erofs/unzip_pagevec.h
+++ b/drivers/staging/erofs/unzip_pagevec.h
@@ -150,7 +150,7 @@ z_erofs_pagevec_ctor_dequeue(struct z_er
 	erofs_vtptr_t t;
 
 	if (unlikely(ctor->index >= ctor->nr)) {
-		BUG_ON(ctor->next == NULL);
+		DBG_BUGON(!ctor->next);
 		z_erofs_pagevec_ctor_pagedown(ctor, true);
 	}
 
--- a/drivers/staging/erofs/unzip_vle.c
+++ b/drivers/staging/erofs/unzip_vle.c
@@ -20,9 +20,6 @@ static struct kmem_cache *z_erofs_workgr
 
 void z_erofs_exit_zip_subsystem(void)
 {
-	BUG_ON(z_erofs_workqueue == NULL);
-	BUG_ON(z_erofs_workgroup_cachep == NULL);
-
 	destroy_workqueue(z_erofs_workqueue);
 	kmem_cache_destroy(z_erofs_workgroup_cachep);
 }
@@ -366,7 +363,10 @@ z_erofs_vle_work_register(const struct z
 	struct z_erofs_vle_work *work;
 
 	/* if multiref is disabled, grp should never be nullptr */
-	BUG_ON(grp != NULL);
+	if (unlikely(grp)) {
+		DBG_BUGON(1);
+		return ERR_PTR(-EINVAL);
+	}
 
 	/* no available workgroup, let's allocate one */
 	grp = kmem_cache_zalloc(z_erofs_workgroup_cachep, GFP_NOFS);
@@ -745,7 +745,7 @@ static inline void z_erofs_vle_read_endi
 		bool cachemngd = false;
 
 		DBG_BUGON(PageUptodate(page));
-		BUG_ON(page->mapping == NULL);
+		DBG_BUGON(!page->mapping);
 
 #ifdef EROFS_FS_HAS_MANAGED_CACHE
 		if (unlikely(mngda == NULL && !z_erofs_is_stagingpage(page))) {
@@ -803,7 +803,7 @@ static int z_erofs_vle_unzip(struct supe
 
 	might_sleep();
 	work = z_erofs_vle_grab_primary_work(grp);
-	BUG_ON(!READ_ONCE(work->nr_pages));
+	DBG_BUGON(!READ_ONCE(work->nr_pages));
 
 	mutex_lock(&work->lock);
 	nr_pages = work->nr_pages;
@@ -852,8 +852,8 @@ repeat:
 		else
 			pagenr = z_erofs_onlinepage_index(page);
 
-		BUG_ON(pagenr >= nr_pages);
-		BUG_ON(pages[pagenr] != NULL);
+		DBG_BUGON(pagenr >= nr_pages);
+		DBG_BUGON(pages[pagenr]);
 
 		pages[pagenr] = page;
 	}
@@ -876,9 +876,8 @@ repeat:
 		if (z_erofs_is_stagingpage(page))
 			continue;
 #ifdef EROFS_FS_HAS_MANAGED_CACHE
-		else if (page->mapping == mngda) {
-			BUG_ON(PageLocked(page));
-			BUG_ON(!PageUptodate(page));
+		if (page->mapping == mngda) {
+			DBG_BUGON(!PageUptodate(page));
 			continue;
 		}
 #endif
@@ -886,8 +885,8 @@ repeat:
 		/* only non-head page could be reused as a compressed page */
 		pagenr = z_erofs_onlinepage_index(page);
 
-		BUG_ON(pagenr >= nr_pages);
-		BUG_ON(pages[pagenr] != NULL);
+		DBG_BUGON(pagenr >= nr_pages);
+		DBG_BUGON(pages[pagenr]);
 		++sparsemem_pages;
 		pages[pagenr] = page;
 
@@ -897,9 +896,6 @@ repeat:
 	llen = (nr_pages << PAGE_SHIFT) - work->pageofs;
 
 	if (z_erofs_vle_workgrp_fmt(grp) == Z_EROFS_VLE_WORKGRP_FMT_PLAIN) {
-		/* FIXME! this should be fixed in the future */
-		BUG_ON(grp->llen != llen);
-
 		err = z_erofs_vle_plain_copy(compressed_pages, clusterpages,
 			pages, nr_pages, work->pageofs);
 		goto out;
@@ -914,10 +910,8 @@ repeat:
 	if (err != -ENOTSUPP)
 		goto out_percpu;
 
-	if (sparsemem_pages >= nr_pages) {
-		BUG_ON(sparsemem_pages > nr_pages);
+	if (sparsemem_pages >= nr_pages)
 		goto skip_allocpage;
-	}
 
 	for (i = 0; i < nr_pages; ++i) {
 		if (pages[i] != NULL)
@@ -1010,7 +1004,7 @@ static void z_erofs_vle_unzip_wq(struct
 		struct z_erofs_vle_unzip_io_sb, io.u.work);
 	LIST_HEAD(page_pool);
 
-	BUG_ON(iosb->io.head == Z_EROFS_VLE_WORKGRP_TAIL_CLOSED);
+	DBG_BUGON(iosb->io.head == Z_EROFS_VLE_WORKGRP_TAIL_CLOSED);
 	z_erofs_vle_unzip_all(iosb->sb, &iosb->io, &page_pool);
 
 	put_pages_list(&page_pool);
@@ -1344,7 +1338,6 @@ static int z_erofs_vle_normalaccess_read
 			continue;
 		}
 
-		BUG_ON(PagePrivate(page));
 		set_page_private(page, (unsigned long)head);
 		head = page;
 	}