From: Dan Carpenter <dan.carpenter@oracle.com>
To: kbuild@lists.01.org
Subject: Re: [fuse:submounts 12/24] fs/fuse/dax.c:399:6: warning: Variable 'ret' is reassigned a value before the old one has been used.
Date: Mon, 21 Sep 2020 11:51:39 +0300 [thread overview]
Message-ID: <20200921085139.GT18329@kadam> (raw)
In-Reply-To: <202009182344.X3QA9BMJ%lkp@intel.com>
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These "reassigned a value before the old one has been used" warnings
are not useful at all because it ignores gotos so it's just false
positives.
regards,
dan carpenter
On Fri, Sep 18, 2020 at 11:07:48PM +0800, kernel test robot wrote:
> CC: kbuild-all(a)lists.01.org
> CC: fuse-devel(a)lists.sourceforge.net
> TO: Vivek Goyal <vgoyal@redhat.com>
> CC: Miklos Szeredi <mszeredi@redhat.com>
> CC: Stefan Hajnoczi <stefanha@redhat.com>
> CC: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
> CC: Liu Bo <bo.liu@linux.alibaba.com>
> CC: Peng Tao <tao.peng@linux.alibaba.com>
>
> tree: https://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse.git submounts
> head: b67fbd48cdf38c6bcc83b2a0e94b32ebeff3c918
> commit: c2d0ad00d948de73c78f05d2b3e5bdfa605035cc [12/24] virtiofs: implement dax read/write operations
> :::::: branch date: 2 hours ago
> :::::: commit date: 8 days ago
> compiler: gcc-9 (Debian 9.3.0-15) 9.3.0
>
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
>
>
> cppcheck warnings: (new ones prefixed by >>)
>
> >> fs/fuse/dax.c:399:6: warning: Variable 'ret' is reassigned a value before the old one has been used. [redundantAssignment]
> ret = fuse_setup_one_mapping(inode, pos >> FUSE_DAX_SHIFT, dmap, true,
> ^
> fs/fuse/dax.c:385:6: note: Variable 'ret' is reassigned a value before the old one has been used.
> ret = -EIO;
> ^
> fs/fuse/dax.c:399:6: note: Variable 'ret' is reassigned a value before the old one has been used.
> ret = fuse_setup_one_mapping(inode, pos >> FUSE_DAX_SHIFT, dmap, true,
> ^
>
> # https://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse.git/commit/?id=c2d0ad00d948de73c78f05d2b3e5bdfa605035cc
> git remote add fuse https://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse.git
> git fetch --no-tags fuse submounts
> git checkout c2d0ad00d948de73c78f05d2b3e5bdfa605035cc
> vim +/ret +399 fs/fuse/dax.c
>
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 362
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 363 static int fuse_upgrade_dax_mapping(struct inode *inode, loff_t pos,
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 364 loff_t length, unsigned int flags,
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 365 struct iomap *iomap)
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 366 {
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 367 struct fuse_inode *fi = get_fuse_inode(inode);
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 368 struct fuse_dax_mapping *dmap;
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 369 int ret;
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 370 unsigned long idx = pos >> FUSE_DAX_SHIFT;
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 371 struct interval_tree_node *node;
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 372
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 373 /*
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 374 * Take exclusive lock so that only one caller can try to setup
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 375 * mapping and others wait.
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 376 */
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 377 down_write(&fi->dax->sem);
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 378 node = interval_tree_iter_first(&fi->dax->tree, idx, idx);
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 379
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 380 /* We are holding either inode lock or i_mmap_sem, and that should
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 381 * ensure that dmap can't reclaimed or truncated and it should still
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 382 * be there in tree despite the fact we dropped and re-acquired the
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 383 * lock.
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 384 */
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 385 ret = -EIO;
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 386 if (WARN_ON(!node))
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 387 goto out_err;
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 388
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 389 dmap = node_to_dmap(node);
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 390
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 391 /* Maybe another thread already upgraded mapping while we were not
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 392 * holding lock.
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 393 */
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 394 if (dmap->writable) {
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 395 ret = 0;
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 396 goto out_fill_iomap;
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 397 }
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 398
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 @399 ret = fuse_setup_one_mapping(inode, pos >> FUSE_DAX_SHIFT, dmap, true,
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 400 true);
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 401 if (ret < 0)
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 402 goto out_err;
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 403 out_fill_iomap:
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 404 fuse_fill_iomap(inode, pos, length, iomap, dmap, flags);
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 405 out_err:
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 406 up_write(&fi->dax->sem);
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 407 return ret;
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 408 }
> c2d0ad00d948de7 Vivek Goyal 2020-08-19 409
>
> ---
> 0-DAY CI Kernel Test Service, Intel Corporation
> https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org
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prev parent reply other threads:[~2020-09-21 8:51 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-18 15:07 [fuse:submounts 12/24] fs/fuse/dax.c:399:6: warning: Variable 'ret' is reassigned a value before the old one has been used kernel test robot
2020-09-21 8:51 ` Dan Carpenter [this message]
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