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* fs/fuse/virtio_fs.c:1009:6: warning: Variable 'err' is reassigned a value before the old one has been used.
@ 2020-08-06  6:04 ` kernel test robot
  0 siblings, 0 replies; 6+ messages in thread
From: kernel test robot @ 2020-08-06  6:04 UTC (permalink / raw)
  To: Stefan Hajnoczi; +Cc: kbuild-all, linux-kernel, Miklos Szeredi, Vivek Goyal

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   fffe3ae0ee84e25d2befe2ae59bc32aa2b6bc77b
commit: a62a8ef9d97da23762a588592c8b8eb50a8deb6a virtio-fs: add virtiofs filesystem
date:   11 months 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/virtio_fs.c:1009:6: warning: Variable 'err' is reassigned a value before the old one has been used. [redundantAssignment]
    err = -ENOMEM;
        ^
   fs/fuse/virtio_fs.c:1003:6: note: Variable 'err' is reassigned a value before the old one has been used.
    err = -EINVAL;
        ^
   fs/fuse/virtio_fs.c:1009:6: note: Variable 'err' is reassigned a value before the old one has been used.
    err = -ENOMEM;
        ^
   fs/fuse/virtio_fs.c:1020:6: warning: Variable 'err' is reassigned a value before the old one has been used. [redundantAssignment]
    err = fuse_fill_super_common(sb, &ctx);
        ^
   fs/fuse/virtio_fs.c:1009:6: note: Variable 'err' is reassigned a value before the old one has been used.
    err = -ENOMEM;
        ^
   fs/fuse/virtio_fs.c:1020:6: note: Variable 'err' is reassigned a value before the old one has been used.
    err = fuse_fill_super_common(sb, &ctx);
        ^

vim +/err +1009 fs/fuse/virtio_fs.c

   979	
   980	static int virtio_fs_fill_super(struct super_block *sb)
   981	{
   982		struct fuse_conn *fc = get_fuse_conn_super(sb);
   983		struct virtio_fs *fs = fc->iq.priv;
   984		unsigned int i;
   985		int err;
   986		struct fuse_fs_context ctx = {
   987			.rootmode = S_IFDIR,
   988			.default_permissions = 1,
   989			.allow_other = 1,
   990			.max_read = UINT_MAX,
   991			.blksize = 512,
   992			.destroy = true,
   993			.no_control = true,
   994			.no_force_umount = true,
   995		};
   996	
   997		mutex_lock(&virtio_fs_mutex);
   998	
   999		/* After holding mutex, make sure virtiofs device is still there.
  1000		 * Though we are holding a reference to it, drive ->remove might
  1001		 * still have cleaned up virtual queues. In that case bail out.
  1002		 */
  1003		err = -EINVAL;
  1004		if (list_empty(&fs->list)) {
  1005			pr_info("virtio-fs: tag <%s> not found\n", fs->tag);
  1006			goto err;
  1007		}
  1008	
> 1009		err = -ENOMEM;
  1010		/* Allocate fuse_dev for hiprio and notification queues */
  1011		for (i = 0; i < VQ_REQUEST; i++) {
  1012			struct virtio_fs_vq *fsvq = &fs->vqs[i];
  1013	
  1014			fsvq->fud = fuse_dev_alloc();
  1015			if (!fsvq->fud)
  1016				goto err_free_fuse_devs;
  1017		}
  1018	
  1019		ctx.fudptr = (void **)&fs->vqs[VQ_REQUEST].fud;
  1020		err = fuse_fill_super_common(sb, &ctx);
  1021		if (err < 0)
  1022			goto err_free_fuse_devs;
  1023	
  1024		fc = fs->vqs[VQ_REQUEST].fud->fc;
  1025	
  1026		for (i = 0; i < fs->nvqs; i++) {
  1027			struct virtio_fs_vq *fsvq = &fs->vqs[i];
  1028	
  1029			if (i == VQ_REQUEST)
  1030				continue; /* already initialized */
  1031			fuse_dev_install(fsvq->fud, fc);
  1032		}
  1033	
  1034		/* Previous unmount will stop all queues. Start these again */
  1035		virtio_fs_start_all_queues(fs);
  1036		fuse_send_init(fc);
  1037		mutex_unlock(&virtio_fs_mutex);
  1038		return 0;
  1039	
  1040	err_free_fuse_devs:
  1041		virtio_fs_free_devs(fs);
  1042	err:
  1043		mutex_unlock(&virtio_fs_mutex);
  1044		return err;
  1045	}
  1046	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

^ permalink raw reply	[flat|nested] 6+ messages in thread
* fs/fuse/virtio_fs.c:1009:6: warning: Variable 'err' is reassigned a value before the old one has been used.
@ 2020-08-06  6:04 ` kernel test robot
  0 siblings, 0 replies; 6+ messages in thread
From: kernel test robot @ 2020-08-06  6:04 UTC (permalink / raw)
  To: kbuild-all

[-- Attachment #1: Type: text/plain, Size: 3680 bytes --]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   fffe3ae0ee84e25d2befe2ae59bc32aa2b6bc77b
commit: a62a8ef9d97da23762a588592c8b8eb50a8deb6a virtio-fs: add virtiofs filesystem
date:   11 months 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/virtio_fs.c:1009:6: warning: Variable 'err' is reassigned a value before the old one has been used. [redundantAssignment]
    err = -ENOMEM;
        ^
   fs/fuse/virtio_fs.c:1003:6: note: Variable 'err' is reassigned a value before the old one has been used.
    err = -EINVAL;
        ^
   fs/fuse/virtio_fs.c:1009:6: note: Variable 'err' is reassigned a value before the old one has been used.
    err = -ENOMEM;
        ^
   fs/fuse/virtio_fs.c:1020:6: warning: Variable 'err' is reassigned a value before the old one has been used. [redundantAssignment]
    err = fuse_fill_super_common(sb, &ctx);
        ^
   fs/fuse/virtio_fs.c:1009:6: note: Variable 'err' is reassigned a value before the old one has been used.
    err = -ENOMEM;
        ^
   fs/fuse/virtio_fs.c:1020:6: note: Variable 'err' is reassigned a value before the old one has been used.
    err = fuse_fill_super_common(sb, &ctx);
        ^

vim +/err +1009 fs/fuse/virtio_fs.c

   979	
   980	static int virtio_fs_fill_super(struct super_block *sb)
   981	{
   982		struct fuse_conn *fc = get_fuse_conn_super(sb);
   983		struct virtio_fs *fs = fc->iq.priv;
   984		unsigned int i;
   985		int err;
   986		struct fuse_fs_context ctx = {
   987			.rootmode = S_IFDIR,
   988			.default_permissions = 1,
   989			.allow_other = 1,
   990			.max_read = UINT_MAX,
   991			.blksize = 512,
   992			.destroy = true,
   993			.no_control = true,
   994			.no_force_umount = true,
   995		};
   996	
   997		mutex_lock(&virtio_fs_mutex);
   998	
   999		/* After holding mutex, make sure virtiofs device is still there.
  1000		 * Though we are holding a reference to it, drive ->remove might
  1001		 * still have cleaned up virtual queues. In that case bail out.
  1002		 */
  1003		err = -EINVAL;
  1004		if (list_empty(&fs->list)) {
  1005			pr_info("virtio-fs: tag <%s> not found\n", fs->tag);
  1006			goto err;
  1007		}
  1008	
> 1009		err = -ENOMEM;
  1010		/* Allocate fuse_dev for hiprio and notification queues */
  1011		for (i = 0; i < VQ_REQUEST; i++) {
  1012			struct virtio_fs_vq *fsvq = &fs->vqs[i];
  1013	
  1014			fsvq->fud = fuse_dev_alloc();
  1015			if (!fsvq->fud)
  1016				goto err_free_fuse_devs;
  1017		}
  1018	
  1019		ctx.fudptr = (void **)&fs->vqs[VQ_REQUEST].fud;
  1020		err = fuse_fill_super_common(sb, &ctx);
  1021		if (err < 0)
  1022			goto err_free_fuse_devs;
  1023	
  1024		fc = fs->vqs[VQ_REQUEST].fud->fc;
  1025	
  1026		for (i = 0; i < fs->nvqs; i++) {
  1027			struct virtio_fs_vq *fsvq = &fs->vqs[i];
  1028	
  1029			if (i == VQ_REQUEST)
  1030				continue; /* already initialized */
  1031			fuse_dev_install(fsvq->fud, fc);
  1032		}
  1033	
  1034		/* Previous unmount will stop all queues. Start these again */
  1035		virtio_fs_start_all_queues(fs);
  1036		fuse_send_init(fc);
  1037		mutex_unlock(&virtio_fs_mutex);
  1038		return 0;
  1039	
  1040	err_free_fuse_devs:
  1041		virtio_fs_free_devs(fs);
  1042	err:
  1043		mutex_unlock(&virtio_fs_mutex);
  1044		return err;
  1045	}
  1046	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org

^ permalink raw reply	[flat|nested] 6+ messages in thread
* Re: fs/fuse/virtio_fs.c:1009:6: warning: Variable 'err' is reassigned a value before the old one has been used.
  2020-08-06  6:04 ` kernel test robot
@ 2020-08-06 17:40   ` Vivek Goyal
  -1 siblings, 0 replies; 6+ messages in thread
From: Vivek Goyal @ 2020-08-06 17:40 UTC (permalink / raw)
  To: kernel test robot
  Cc: Stefan Hajnoczi, kbuild-all, linux-kernel, Miklos Szeredi

On Thu, Aug 06, 2020 at 02:04:18PM +0800, kernel test robot wrote:
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head:   fffe3ae0ee84e25d2befe2ae59bc32aa2b6bc77b
> commit: a62a8ef9d97da23762a588592c8b8eb50a8deb6a virtio-fs: add virtiofs filesystem
> date:   11 months 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/virtio_fs.c:1009:6: warning: Variable 'err' is reassigned a value before the old one has been used. [redundantAssignment]
>     err = -ENOMEM;
>         ^
>    fs/fuse/virtio_fs.c:1003:6: note: Variable 'err' is reassigned a value before the old one has been used.
>     err = -EINVAL;
>         ^
>    fs/fuse/virtio_fs.c:1009:6: note: Variable 'err' is reassigned a value before the old one has been used.
>     err = -ENOMEM;
>         ^
>    fs/fuse/virtio_fs.c:1020:6: warning: Variable 'err' is reassigned a value before the old one has been used. [redundantAssignment]
>     err = fuse_fill_super_common(sb, &ctx);
>         ^
>    fs/fuse/virtio_fs.c:1009:6: note: Variable 'err' is reassigned a value before the old one has been used.
>     err = -ENOMEM;

Not sure why this is a warning. Previous value is not going to be used
anymore. If it were to be used, we would have taken "goto err" path,
and return err. Very fact that we did not take that path means we
are not going to use previous value of err, hence it is ok to override
it. 

IOW, this seems like a false warning from compiler. This pattern has been
used in fuse and overlayfs code all over the place.

Thanks
Vivek

>         ^
>    fs/fuse/virtio_fs.c:1020:6: note: Variable 'err' is reassigned a value before the old one has been used.
>     err = fuse_fill_super_common(sb, &ctx);
>         ^
> 
> vim +/err +1009 fs/fuse/virtio_fs.c
> 
>    979	
>    980	static int virtio_fs_fill_super(struct super_block *sb)
>    981	{
>    982		struct fuse_conn *fc = get_fuse_conn_super(sb);
>    983		struct virtio_fs *fs = fc->iq.priv;
>    984		unsigned int i;
>    985		int err;
>    986		struct fuse_fs_context ctx = {
>    987			.rootmode = S_IFDIR,
>    988			.default_permissions = 1,
>    989			.allow_other = 1,
>    990			.max_read = UINT_MAX,
>    991			.blksize = 512,
>    992			.destroy = true,
>    993			.no_control = true,
>    994			.no_force_umount = true,
>    995		};
>    996	
>    997		mutex_lock(&virtio_fs_mutex);
>    998	
>    999		/* After holding mutex, make sure virtiofs device is still there.
>   1000		 * Though we are holding a reference to it, drive ->remove might
>   1001		 * still have cleaned up virtual queues. In that case bail out.
>   1002		 */
>   1003		err = -EINVAL;
>   1004		if (list_empty(&fs->list)) {
>   1005			pr_info("virtio-fs: tag <%s> not found\n", fs->tag);
>   1006			goto err;
>   1007		}
>   1008	
> > 1009		err = -ENOMEM;
>   1010		/* Allocate fuse_dev for hiprio and notification queues */
>   1011		for (i = 0; i < VQ_REQUEST; i++) {
>   1012			struct virtio_fs_vq *fsvq = &fs->vqs[i];
>   1013	
>   1014			fsvq->fud = fuse_dev_alloc();
>   1015			if (!fsvq->fud)
>   1016				goto err_free_fuse_devs;
>   1017		}
>   1018	
>   1019		ctx.fudptr = (void **)&fs->vqs[VQ_REQUEST].fud;
>   1020		err = fuse_fill_super_common(sb, &ctx);
>   1021		if (err < 0)
>   1022			goto err_free_fuse_devs;
>   1023	
>   1024		fc = fs->vqs[VQ_REQUEST].fud->fc;
>   1025	
>   1026		for (i = 0; i < fs->nvqs; i++) {
>   1027			struct virtio_fs_vq *fsvq = &fs->vqs[i];
>   1028	
>   1029			if (i == VQ_REQUEST)
>   1030				continue; /* already initialized */
>   1031			fuse_dev_install(fsvq->fud, fc);
>   1032		}
>   1033	
>   1034		/* Previous unmount will stop all queues. Start these again */
>   1035		virtio_fs_start_all_queues(fs);
>   1036		fuse_send_init(fc);
>   1037		mutex_unlock(&virtio_fs_mutex);
>   1038		return 0;
>   1039	
>   1040	err_free_fuse_devs:
>   1041		virtio_fs_free_devs(fs);
>   1042	err:
>   1043		mutex_unlock(&virtio_fs_mutex);
>   1044		return err;
>   1045	}
>   1046	
> 
> ---
> 0-DAY CI Kernel Test Service, Intel Corporation
> https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
> 


^ permalink raw reply	[flat|nested] 6+ messages in thread
* Re: fs/fuse/virtio_fs.c:1009:6: warning: Variable 'err' is reassigned a value before the old one has been used.
@ 2020-08-06 17:40   ` Vivek Goyal
  0 siblings, 0 replies; 6+ messages in thread
From: Vivek Goyal @ 2020-08-06 17:40 UTC (permalink / raw)
  To: kbuild-all

[-- Attachment #1: Type: text/plain, Size: 4402 bytes --]

On Thu, Aug 06, 2020 at 02:04:18PM +0800, kernel test robot wrote:
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head:   fffe3ae0ee84e25d2befe2ae59bc32aa2b6bc77b
> commit: a62a8ef9d97da23762a588592c8b8eb50a8deb6a virtio-fs: add virtiofs filesystem
> date:   11 months 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/virtio_fs.c:1009:6: warning: Variable 'err' is reassigned a value before the old one has been used. [redundantAssignment]
>     err = -ENOMEM;
>         ^
>    fs/fuse/virtio_fs.c:1003:6: note: Variable 'err' is reassigned a value before the old one has been used.
>     err = -EINVAL;
>         ^
>    fs/fuse/virtio_fs.c:1009:6: note: Variable 'err' is reassigned a value before the old one has been used.
>     err = -ENOMEM;
>         ^
>    fs/fuse/virtio_fs.c:1020:6: warning: Variable 'err' is reassigned a value before the old one has been used. [redundantAssignment]
>     err = fuse_fill_super_common(sb, &ctx);
>         ^
>    fs/fuse/virtio_fs.c:1009:6: note: Variable 'err' is reassigned a value before the old one has been used.
>     err = -ENOMEM;

Not sure why this is a warning. Previous value is not going to be used
anymore. If it were to be used, we would have taken "goto err" path,
and return err. Very fact that we did not take that path means we
are not going to use previous value of err, hence it is ok to override
it. 

IOW, this seems like a false warning from compiler. This pattern has been
used in fuse and overlayfs code all over the place.

Thanks
Vivek

>         ^
>    fs/fuse/virtio_fs.c:1020:6: note: Variable 'err' is reassigned a value before the old one has been used.
>     err = fuse_fill_super_common(sb, &ctx);
>         ^
> 
> vim +/err +1009 fs/fuse/virtio_fs.c
> 
>    979	
>    980	static int virtio_fs_fill_super(struct super_block *sb)
>    981	{
>    982		struct fuse_conn *fc = get_fuse_conn_super(sb);
>    983		struct virtio_fs *fs = fc->iq.priv;
>    984		unsigned int i;
>    985		int err;
>    986		struct fuse_fs_context ctx = {
>    987			.rootmode = S_IFDIR,
>    988			.default_permissions = 1,
>    989			.allow_other = 1,
>    990			.max_read = UINT_MAX,
>    991			.blksize = 512,
>    992			.destroy = true,
>    993			.no_control = true,
>    994			.no_force_umount = true,
>    995		};
>    996	
>    997		mutex_lock(&virtio_fs_mutex);
>    998	
>    999		/* After holding mutex, make sure virtiofs device is still there.
>   1000		 * Though we are holding a reference to it, drive ->remove might
>   1001		 * still have cleaned up virtual queues. In that case bail out.
>   1002		 */
>   1003		err = -EINVAL;
>   1004		if (list_empty(&fs->list)) {
>   1005			pr_info("virtio-fs: tag <%s> not found\n", fs->tag);
>   1006			goto err;
>   1007		}
>   1008	
> > 1009		err = -ENOMEM;
>   1010		/* Allocate fuse_dev for hiprio and notification queues */
>   1011		for (i = 0; i < VQ_REQUEST; i++) {
>   1012			struct virtio_fs_vq *fsvq = &fs->vqs[i];
>   1013	
>   1014			fsvq->fud = fuse_dev_alloc();
>   1015			if (!fsvq->fud)
>   1016				goto err_free_fuse_devs;
>   1017		}
>   1018	
>   1019		ctx.fudptr = (void **)&fs->vqs[VQ_REQUEST].fud;
>   1020		err = fuse_fill_super_common(sb, &ctx);
>   1021		if (err < 0)
>   1022			goto err_free_fuse_devs;
>   1023	
>   1024		fc = fs->vqs[VQ_REQUEST].fud->fc;
>   1025	
>   1026		for (i = 0; i < fs->nvqs; i++) {
>   1027			struct virtio_fs_vq *fsvq = &fs->vqs[i];
>   1028	
>   1029			if (i == VQ_REQUEST)
>   1030				continue; /* already initialized */
>   1031			fuse_dev_install(fsvq->fud, fc);
>   1032		}
>   1033	
>   1034		/* Previous unmount will stop all queues. Start these again */
>   1035		virtio_fs_start_all_queues(fs);
>   1036		fuse_send_init(fc);
>   1037		mutex_unlock(&virtio_fs_mutex);
>   1038		return 0;
>   1039	
>   1040	err_free_fuse_devs:
>   1041		virtio_fs_free_devs(fs);
>   1042	err:
>   1043		mutex_unlock(&virtio_fs_mutex);
>   1044		return err;
>   1045	}
>   1046	
> 
> ---
> 0-DAY CI Kernel Test Service, Intel Corporation
> https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org
> 

^ permalink raw reply	[flat|nested] 6+ messages in thread
* RE: [kbuild-all] Re: fs/fuse/virtio_fs.c:1009:6: warning: Variable 'err' is reassigned a value before the old one has been used.
  2020-08-06 17:40   ` Vivek Goyal
@ 2020-08-10  9:24     ` Xia, Hui
  -1 siblings, 0 replies; 6+ messages in thread
From: Xia, Hui @ 2020-08-10  9:24 UTC (permalink / raw)
  To: Vivek Goyal, lkp
  Cc: Stefan Hajnoczi, kbuild-all, linux-kernel, Miklos Szeredi



>-----Original Message-----
>From: Vivek Goyal <vgoyal@redhat.com>
>Sent: 2020年8月7日 1:41
>To: kernel test robot <lkp@intel.com>
>Cc: Stefan Hajnoczi <stefanha@redhat.com>; kbuild-all@lists.01.org; linux-
>kernel@vger.kernel.org; Miklos Szeredi <mszeredi@redhat.com>
>Subject: [kbuild-all] Re: fs/fuse/virtio_fs.c:1009:6: warning: Variable 'err' is
>reassigned a value before the old one has been used.
>
>On Thu, Aug 06, 2020 at 02:04:18PM +0800, kernel test robot wrote:
>> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
>> head:   fffe3ae0ee84e25d2befe2ae59bc32aa2b6bc77b
>> commit: a62a8ef9d97da23762a588592c8b8eb50a8deb6a virtio-fs: add virtiofs
>filesystem
>> date:   11 months 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/virtio_fs.c:1009:6: warning: Variable 'err' is reassigned a
>> >> value before the old one has been used. [redundantAssignment]
>>     err = -ENOMEM;
>>         ^
>>    fs/fuse/virtio_fs.c:1003:6: note: Variable 'err' is reassigned a value before the
>old one has been used.
>>     err = -EINVAL;
>>         ^
>>    fs/fuse/virtio_fs.c:1009:6: note: Variable 'err' is reassigned a value before the
>old one has been used.
>>     err = -ENOMEM;
>>         ^
>>    fs/fuse/virtio_fs.c:1020:6: warning: Variable 'err' is reassigned a value before
>the old one has been used. [redundantAssignment]
>>     err = fuse_fill_super_common(sb, &ctx);
>>         ^
>>    fs/fuse/virtio_fs.c:1009:6: note: Variable 'err' is reassigned a value before the
>old one has been used.
>>     err = -ENOMEM;
>
>Not sure why this is a warning. Previous value is not going to be used anymore. If
>it were to be used, we would have taken "goto err" path, and return err. Very fact
>that we did not take that path means we are not going to use previous value of
>err, hence it is ok to override it.
>
>IOW, this seems like a false warning from compiler. This pattern has been used in
>fuse and overlayfs code all over the place.

Thanks, Vivek. Please ignore this report.
We will double check this type of warning before send report in future. Sorry for inconvenient.

Thanks,
Hui

>
>Thanks
>Vivek
>
>>         ^
>>    fs/fuse/virtio_fs.c:1020:6: note: Variable 'err' is reassigned a value before the
>old one has been used.
>>     err = fuse_fill_super_common(sb, &ctx);
>>         ^
>>
>> vim +/err +1009 fs/fuse/virtio_fs.c
>>
>>    979
>>    980	static int virtio_fs_fill_super(struct super_block *sb)
>>    981	{
>>    982		struct fuse_conn *fc = get_fuse_conn_super(sb);
>>    983		struct virtio_fs *fs = fc->iq.priv;
>>    984		unsigned int i;
>>    985		int err;
>>    986		struct fuse_fs_context ctx = {
>>    987			.rootmode = S_IFDIR,
>>    988			.default_permissions = 1,
>>    989			.allow_other = 1,
>>    990			.max_read = UINT_MAX,
>>    991			.blksize = 512,
>>    992			.destroy = true,
>>    993			.no_control = true,
>>    994			.no_force_umount = true,
>>    995		};
>>    996
>>    997		mutex_lock(&virtio_fs_mutex);
>>    998
>>    999		/* After holding mutex, make sure virtiofs device is still there.
>>   1000		 * Though we are holding a reference to it, drive ->remove might
>>   1001		 * still have cleaned up virtual queues. In that case bail out.
>>   1002		 */
>>   1003		err = -EINVAL;
>>   1004		if (list_empty(&fs->list)) {
>>   1005			pr_info("virtio-fs: tag <%s> not found\n", fs->tag);
>>   1006			goto err;
>>   1007		}
>>   1008
>> > 1009		err = -ENOMEM;
>>   1010		/* Allocate fuse_dev for hiprio and notification queues */
>>   1011		for (i = 0; i < VQ_REQUEST; i++) {
>>   1012			struct virtio_fs_vq *fsvq = &fs->vqs[i];
>>   1013
>>   1014			fsvq->fud = fuse_dev_alloc();
>>   1015			if (!fsvq->fud)
>>   1016				goto err_free_fuse_devs;
>>   1017		}
>>   1018
>>   1019		ctx.fudptr = (void **)&fs->vqs[VQ_REQUEST].fud;
>>   1020		err = fuse_fill_super_common(sb, &ctx);
>>   1021		if (err < 0)
>>   1022			goto err_free_fuse_devs;
>>   1023
>>   1024		fc = fs->vqs[VQ_REQUEST].fud->fc;
>>   1025
>>   1026		for (i = 0; i < fs->nvqs; i++) {
>>   1027			struct virtio_fs_vq *fsvq = &fs->vqs[i];
>>   1028
>>   1029			if (i == VQ_REQUEST)
>>   1030				continue; /* already initialized */
>>   1031			fuse_dev_install(fsvq->fud, fc);
>>   1032		}
>>   1033
>>   1034		/* Previous unmount will stop all queues. Start these again */
>>   1035		virtio_fs_start_all_queues(fs);
>>   1036		fuse_send_init(fc);
>>   1037		mutex_unlock(&virtio_fs_mutex);
>>   1038		return 0;
>>   1039
>>   1040	err_free_fuse_devs:
>>   1041		virtio_fs_free_devs(fs);
>>   1042	err:
>>   1043		mutex_unlock(&virtio_fs_mutex);
>>   1044		return err;
>>   1045	}
>>   1046
>>
>> ---
>> 0-DAY CI Kernel Test Service, Intel Corporation
>> https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
>>
>_______________________________________________
>kbuild-all mailing list -- kbuild-all@lists.01.org To unsubscribe send an email to
>kbuild-all-leave@lists.01.org

^ permalink raw reply	[flat|nested] 6+ messages in thread
* Re: fs/fuse/virtio_fs.c:1009:6: warning: Variable 'err' is reassigned a value before the old one has been used.
@ 2020-08-10  9:24     ` Xia, Hui
  0 siblings, 0 replies; 6+ messages in thread
From: Xia, Hui @ 2020-08-10  9:24 UTC (permalink / raw)
  To: kbuild-all

[-- Attachment #1: Type: text/plain, Size: 5274 bytes --]



>-----Original Message-----
>From: Vivek Goyal <vgoyal@redhat.com>
>Sent: 2020年8月7日 1:41
>To: kernel test robot <lkp@intel.com>
>Cc: Stefan Hajnoczi <stefanha@redhat.com>; kbuild-all(a)lists.01.org; linux-
>kernel(a)vger.kernel.org; Miklos Szeredi <mszeredi@redhat.com>
>Subject: [kbuild-all] Re: fs/fuse/virtio_fs.c:1009:6: warning: Variable 'err' is
>reassigned a value before the old one has been used.
>
>On Thu, Aug 06, 2020 at 02:04:18PM +0800, kernel test robot wrote:
>> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
>> head:   fffe3ae0ee84e25d2befe2ae59bc32aa2b6bc77b
>> commit: a62a8ef9d97da23762a588592c8b8eb50a8deb6a virtio-fs: add virtiofs
>filesystem
>> date:   11 months 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/virtio_fs.c:1009:6: warning: Variable 'err' is reassigned a
>> >> value before the old one has been used. [redundantAssignment]
>>     err = -ENOMEM;
>>         ^
>>    fs/fuse/virtio_fs.c:1003:6: note: Variable 'err' is reassigned a value before the
>old one has been used.
>>     err = -EINVAL;
>>         ^
>>    fs/fuse/virtio_fs.c:1009:6: note: Variable 'err' is reassigned a value before the
>old one has been used.
>>     err = -ENOMEM;
>>         ^
>>    fs/fuse/virtio_fs.c:1020:6: warning: Variable 'err' is reassigned a value before
>the old one has been used. [redundantAssignment]
>>     err = fuse_fill_super_common(sb, &ctx);
>>         ^
>>    fs/fuse/virtio_fs.c:1009:6: note: Variable 'err' is reassigned a value before the
>old one has been used.
>>     err = -ENOMEM;
>
>Not sure why this is a warning. Previous value is not going to be used anymore. If
>it were to be used, we would have taken "goto err" path, and return err. Very fact
>that we did not take that path means we are not going to use previous value of
>err, hence it is ok to override it.
>
>IOW, this seems like a false warning from compiler. This pattern has been used in
>fuse and overlayfs code all over the place.

Thanks, Vivek. Please ignore this report.
We will double check this type of warning before send report in future. Sorry for inconvenient.

Thanks,
Hui

>
>Thanks
>Vivek
>
>>         ^
>>    fs/fuse/virtio_fs.c:1020:6: note: Variable 'err' is reassigned a value before the
>old one has been used.
>>     err = fuse_fill_super_common(sb, &ctx);
>>         ^
>>
>> vim +/err +1009 fs/fuse/virtio_fs.c
>>
>>    979
>>    980	static int virtio_fs_fill_super(struct super_block *sb)
>>    981	{
>>    982		struct fuse_conn *fc = get_fuse_conn_super(sb);
>>    983		struct virtio_fs *fs = fc->iq.priv;
>>    984		unsigned int i;
>>    985		int err;
>>    986		struct fuse_fs_context ctx = {
>>    987			.rootmode = S_IFDIR,
>>    988			.default_permissions = 1,
>>    989			.allow_other = 1,
>>    990			.max_read = UINT_MAX,
>>    991			.blksize = 512,
>>    992			.destroy = true,
>>    993			.no_control = true,
>>    994			.no_force_umount = true,
>>    995		};
>>    996
>>    997		mutex_lock(&virtio_fs_mutex);
>>    998
>>    999		/* After holding mutex, make sure virtiofs device is still there.
>>   1000		 * Though we are holding a reference to it, drive ->remove might
>>   1001		 * still have cleaned up virtual queues. In that case bail out.
>>   1002		 */
>>   1003		err = -EINVAL;
>>   1004		if (list_empty(&fs->list)) {
>>   1005			pr_info("virtio-fs: tag <%s> not found\n", fs->tag);
>>   1006			goto err;
>>   1007		}
>>   1008
>> > 1009		err = -ENOMEM;
>>   1010		/* Allocate fuse_dev for hiprio and notification queues */
>>   1011		for (i = 0; i < VQ_REQUEST; i++) {
>>   1012			struct virtio_fs_vq *fsvq = &fs->vqs[i];
>>   1013
>>   1014			fsvq->fud = fuse_dev_alloc();
>>   1015			if (!fsvq->fud)
>>   1016				goto err_free_fuse_devs;
>>   1017		}
>>   1018
>>   1019		ctx.fudptr = (void **)&fs->vqs[VQ_REQUEST].fud;
>>   1020		err = fuse_fill_super_common(sb, &ctx);
>>   1021		if (err < 0)
>>   1022			goto err_free_fuse_devs;
>>   1023
>>   1024		fc = fs->vqs[VQ_REQUEST].fud->fc;
>>   1025
>>   1026		for (i = 0; i < fs->nvqs; i++) {
>>   1027			struct virtio_fs_vq *fsvq = &fs->vqs[i];
>>   1028
>>   1029			if (i == VQ_REQUEST)
>>   1030				continue; /* already initialized */
>>   1031			fuse_dev_install(fsvq->fud, fc);
>>   1032		}
>>   1033
>>   1034		/* Previous unmount will stop all queues. Start these again */
>>   1035		virtio_fs_start_all_queues(fs);
>>   1036		fuse_send_init(fc);
>>   1037		mutex_unlock(&virtio_fs_mutex);
>>   1038		return 0;
>>   1039
>>   1040	err_free_fuse_devs:
>>   1041		virtio_fs_free_devs(fs);
>>   1042	err:
>>   1043		mutex_unlock(&virtio_fs_mutex);
>>   1044		return err;
>>   1045	}
>>   1046
>>
>> ---
>> 0-DAY CI Kernel Test Service, Intel Corporation
>> https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org
>>
>_______________________________________________
>kbuild-all mailing list -- kbuild-all(a)lists.01.org To unsubscribe send an email to
>kbuild-all-leave(a)lists.01.org

^ permalink raw reply	[flat|nested] 6+ messages in thread
end of thread, other threads:[~2020-08-10  9:25 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-08-06  6:04 fs/fuse/virtio_fs.c:1009:6: warning: Variable 'err' is reassigned a value before the old one has been used kernel test robot
2020-08-06  6:04 ` kernel test robot
2020-08-06 17:40 ` Vivek Goyal
2020-08-06 17:40   ` Vivek Goyal
2020-08-10  9:24   ` [kbuild-all] " Xia, Hui
2020-08-10  9:24     ` Xia, Hui

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