[ammarfaizi2-block:dhowells/linux-fs/netfs-linked-list 46/61] fs/netfs/buffered_flush.c:243 netfs_check_dirty_list() warn: ignoring unreachable code.

[ammarfaizi2-block:dhowells/linux-fs/netfs-linked-list 46/61] fs/netfs/buffered_flush.c:243 netfs_check_dirty_list() warn: ignoring unreachable code.

[kernel test robot]

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CC: kbuild-all(a)lists.01.org
BCC: lkp(a)intel.com
CC: "GNU/Weeb Mailing List" <gwml@vger.gnuweeb.org>
CC: linux-kernel(a)vger.kernel.org
TO: David Howells <dhowells@redhat.com>

tree:   https://github.com/ammarfaizi2/linux-block dhowells/linux-fs/netfs-linked-list
head:   ce4670495468b797b0c5927fcb661bc0da48b9ab
commit: 2dc27084e13c29183f0a6853b81e5fa2941948e3 [46/61] netfs: Generate a write request from ->writepages()
:::::: branch date: 2 days ago
:::::: commit date: 3 days ago
config: x86_64-randconfig-m001 (https://download.01.org/0day-ci/archive/20220703/202207031839.j9M8ZUnm-lkp(a)intel.com/config)
compiler: gcc-11 (Debian 11.3.0-3) 11.3.0

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>

smatch warnings:
fs/netfs/buffered_flush.c:243 netfs_check_dirty_list() warn: ignoring unreachable code.
fs/netfs/buffered_flush.c:687 netfs_find_writeback_start() error: uninitialized symbol 'ret'.

vim +243 fs/netfs/buffered_flush.c

2dc27084e13c29 David Howells 2021-06-29  233  
2dc27084e13c29 David Howells 2021-06-29  234  void netfs_check_dirty_list(char c, const struct list_head *list,
2dc27084e13c29 David Howells 2021-06-29  235  			    const struct netfs_dirty_region *star)
2dc27084e13c29 David Howells 2021-06-29  236  {
2dc27084e13c29 David Howells 2021-06-29  237  	const struct netfs_dirty_region *r, *q;
2dc27084e13c29 David Howells 2021-06-29  238  	const struct list_head *p;
2dc27084e13c29 David Howells 2021-06-29  239  	int i = 0;
2dc27084e13c29 David Howells 2021-06-29  240  
2dc27084e13c29 David Howells 2021-06-29  241  	return;
2dc27084e13c29 David Howells 2021-06-29  242  
2dc27084e13c29 David Howells 2021-06-29 @243  	if (list->next == list) {
2dc27084e13c29 David Howells 2021-06-29  244  		BUG_ON(list->prev != list);
2dc27084e13c29 David Howells 2021-06-29  245  		return;
2dc27084e13c29 David Howells 2021-06-29  246  	}
2dc27084e13c29 David Howells 2021-06-29  247  	BUG_ON(list->prev == list);
2dc27084e13c29 David Howells 2021-06-29  248  
2dc27084e13c29 David Howells 2021-06-29  249  	list_for_each(p, list) {
2dc27084e13c29 David Howells 2021-06-29  250  		r = list_entry(p, struct netfs_dirty_region, dirty_link);
2dc27084e13c29 David Howells 2021-06-29  251  		if (p->prev->next != p ||
2dc27084e13c29 David Howells 2021-06-29  252  		    p->next->prev != p ||
2dc27084e13c29 David Howells 2021-06-29  253  		    r->last < r->first ||
2dc27084e13c29 David Howells 2021-06-29  254  		    r->from > r->to ||
2dc27084e13c29 David Howells 2021-06-29  255  		    r->from < r->first * PAGE_SIZE ||
2dc27084e13c29 David Howells 2021-06-29  256  		    r->to > (r->last + 1) * PAGE_SIZE)
2dc27084e13c29 David Howells 2021-06-29  257  			goto failed;
2dc27084e13c29 David Howells 2021-06-29  258  		if (!list_is_first(p, list)) {
2dc27084e13c29 David Howells 2021-06-29  259  			q = list_prev_entry(r, dirty_link);
2dc27084e13c29 David Howells 2021-06-29  260  			if (q->last >= r->first)
2dc27084e13c29 David Howells 2021-06-29  261  				goto failed;
2dc27084e13c29 David Howells 2021-06-29  262  		}
2dc27084e13c29 David Howells 2021-06-29  263  	}
2dc27084e13c29 David Howells 2021-06-29  264  
2dc27084e13c29 David Howells 2021-06-29  265  	return;
2dc27084e13c29 David Howells 2021-06-29  266  
2dc27084e13c29 David Howells 2021-06-29  267  failed:
2dc27084e13c29 David Howells 2021-06-29  268  	kdebug("");
2dc27084e13c29 David Howells 2021-06-29  269  	list_for_each(p, list) {
2dc27084e13c29 David Howells 2021-06-29  270  		r = list_entry(p, struct netfs_dirty_region, dirty_link);
2dc27084e13c29 David Howells 2021-06-29  271  		kdebug("CHECK-%c[%x]%c D=%03x %04lx-%04lx %06llx-%06llx",
2dc27084e13c29 David Howells 2021-06-29  272  		       c, i++, r == star ? '*' : ' ',
2dc27084e13c29 David Howells 2021-06-29  273  		       r->debug_id, r->first, r->last, r->from, r->to);
2dc27084e13c29 David Howells 2021-06-29  274  		BUG_ON(p->prev->next != p);
2dc27084e13c29 David Howells 2021-06-29  275  		BUG_ON(p->next->prev != p);
2dc27084e13c29 David Howells 2021-06-29  276  		BUG_ON(r->last < r->first);
2dc27084e13c29 David Howells 2021-06-29  277  		BUG_ON(r->from > r->to);
2dc27084e13c29 David Howells 2021-06-29  278  		BUG_ON(r->from < r->first * PAGE_SIZE);
2dc27084e13c29 David Howells 2021-06-29  279  		BUG_ON(r->to > (r->last + 1) * PAGE_SIZE);
2dc27084e13c29 David Howells 2021-06-29  280  		if (!list_is_first(p, list)) {
2dc27084e13c29 David Howells 2021-06-29  281  			q = list_prev_entry(r, dirty_link);
2dc27084e13c29 David Howells 2021-06-29  282  			BUG_ON(q->last >= r->first);
2dc27084e13c29 David Howells 2021-06-29  283  		}
2dc27084e13c29 David Howells 2021-06-29  284  	}
2dc27084e13c29 David Howells 2021-06-29  285  }
2dc27084e13c29 David Howells 2021-06-29  286  

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