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From:   "Fabio M. De Francesco" <fmdefrancesco@gmail.com>
To:     Chris Mason <chris.mason@fusionio.com>,
        Josef Bacik <josef@toxicpanda.com>,
        David Sterba <dsterba@suse.com>,
        Ira Weiny <ira.weiny@intel.com>, linux-btrfs@vger.kernel.org,
        linux-kernel@vger.kernel.org, kernel test robot <lkp@intel.com>
Cc:     llvm@lists.linux.dev, kbuild-all@lists.01.org
Subject: Re: [PATCH 3/3] btrfs: Replace kmap() with kmap_local_page() in zlib.c
Date:   Wed, 01 Jun 2022 21:57:28 +0200
Message-ID: <3146770.aV6nBDHxoP@opensuse>
In-Reply-To: <202206010437.EX5Nj7cu-lkp@intel.com>
References: <20220531145335.13954-4-fmdefrancesco@gmail.com> <202206010437.EX5Nj7cu-lkp@intel.com>
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On marted=C3=AC 31 maggio 2022 22:35:30 CEST kernel test robot wrote:
> Hi "Fabio,
>=20
> Thank you for the patch! Perhaps something to improve:
>=20

[snip]

> If you fix the issue, kindly add following tag where applicable
> Reported-by: kernel test robot <lkp@intel.com>
>=20
> All warnings (new ones prefixed by >>):
>=20
> >> fs/btrfs/zlib.c:125:6: warning: variable 'data_in' is used=20
uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
>            if (out_page =3D=3D NULL) {
>                ^~~~~~~~~~~~~~~~
>    fs/btrfs/zlib.c:270:6: note: uninitialized use occurs here
>            if (data_in) {
>                ^~~~~~~
>    fs/btrfs/zlib.c:125:2: note: remove the 'if' if its condition is=20
always false
>            if (out_page =3D=3D NULL) {
>            ^~~~~~~~~~~~~~~~~~~~~~~
>    fs/btrfs/zlib.c:115:6: warning: variable 'data_in' is used=20
uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
>            if (Z_OK !=3D zlib_deflateInit(&workspace->strm, workspace-
>level)) {
>               =20
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/zlib.h:148:25: note: expanded from macro 'Z_OK'
>    #define Z_OK            0
>                            ^
>    fs/btrfs/zlib.c:270:6: note: uninitialized use occurs here
>            if (data_in) {
>                ^~~~~~~
>    fs/btrfs/zlib.c:115:2: note: remove the 'if' if its condition is=20
always false
>            if (Z_OK !=3D zlib_deflateInit(&workspace->strm, workspace-
>level)) {
>           =20
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    fs/btrfs/zlib.c:100:15: note: initialize the variable 'data_in' to=20
silence this warning
>            char *data_in;
>                         ^
>                          =3D NULL
> >> fs/btrfs/zlib.c:125:6: warning: variable 'cpage_out' is used=20
uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
>            if (out_page =3D=3D NULL) {
>                ^~~~~~~~~~~~~~~~
>    fs/btrfs/zlib.c:267:6: note: uninitialized use occurs here
>            if (cpage_out)
>                ^~~~~~~~~
>    fs/btrfs/zlib.c:125:2: note: remove the 'if' if its condition is=20
always false
>            if (out_page =3D=3D NULL) {
>            ^~~~~~~~~~~~~~~~~~~~~~~
>    fs/btrfs/zlib.c:115:6: warning: variable 'cpage_out' is used=20
uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
>            if (Z_OK !=3D zlib_deflateInit(&workspace->strm, workspace-
>level)) {
>               =20
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/zlib.h:148:25: note: expanded from macro 'Z_OK'
>    #define Z_OK            0
>                            ^
>    fs/btrfs/zlib.c:267:6: note: uninitialized use occurs here
>            if (cpage_out)
>                ^~~~~~~~~
>    fs/btrfs/zlib.c:115:2: note: remove the 'if' if its condition is=20
always false
>            if (Z_OK !=3D zlib_deflateInit(&workspace->strm, workspace-
>level)) {
>           =20
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    fs/btrfs/zlib.c:101:17: note: initialize the variable 'cpage_out' to=20
silence this warning
>            char *cpage_out;
>                           ^
>                            =3D NULL
>    4 warnings generated.

I'll initialize these variables in v2.

Thanks,

=46abio