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b=ZfAUOrA4+4PzUIlLfwx0pZzjjMSWEwQzTUICw7S+nyRjSvVasQjwzTTKkWt5+VGUU snpNxm8aDorQtx2+eoDhq5hjE7V2fmP1Y4yVZkDZ7Az3sQBzwKR4QqC3jX+LM9X3Rp byiEdTEwUHqvU3eO792QkR3MI00yEyYXKsmZK2FPPX6nutKv/IgkOujyyNDE47XTjG 3GcB+TQpnQVHPf6o7tRjIEnqzPMK7Yvci5uJeqREZ9I18yHVzTq7HrZ62RMHkAYsd+ TPAVJgCyAb24sCuJGpMQUAIqQAVLxRiEHdDtD5g/WI34U22SQM0IrmtRGgQM3jEOj+ izlByCP+HD/Tw== Date: Wed, 28 Aug 2024 12:33:30 +0200 From: Alejandro Colomar To: Yafang Shao Cc: akpm@linux-foundation.org, torvalds@linux-foundation.org, justinstitt@google.com, ebiederm@xmission.com, alexei.starovoitov@gmail.com, rostedt@goodmis.org, catalin.marinas@arm.com, penguin-kernel@i-love.sakura.ne.jp, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, audit@vger.kernel.org, linux-security-module@vger.kernel.org, selinux@vger.kernel.org, bpf@vger.kernel.org, netdev@vger.kernel.org, dri-devel@lists.freedesktop.org, Simon Horman , Matthew Wilcox Subject: Re: [PATCH v8 6/8] mm/util: Deduplicate code in {kstrdup,kstrndup,kmemdup_nul} Message-ID: References: <20240828030321.20688-1-laoar.shao@gmail.com> <20240828030321.20688-7-laoar.shao@gmail.com> MIME-Version: 1.0 Content-Type: multipart/signed; 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protected-headers=v1; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable From: Alejandro Colomar To: Yafang Shao Cc: akpm@linux-foundation.org, torvalds@linux-foundation.org, justinstitt@google.com, ebiederm@xmission.com, alexei.starovoitov@gmail.com, rostedt@goodmis.org, catalin.marinas@arm.com, penguin-kernel@i-love.sakura.ne.jp, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, audit@vger.kernel.org, linux-security-module@vger.kernel.org, selinux@vger.kernel.org, bpf@vger.kernel.org, netdev@vger.kernel.org, dri-devel@lists.freedesktop.org, Simon Horman , Matthew Wilcox Subject: Re: [PATCH v8 6/8] mm/util: Deduplicate code in {kstrdup,kstrndup,kmemdup_nul} References: <20240828030321.20688-1-laoar.shao@gmail.com> <20240828030321.20688-7-laoar.shao@gmail.com> MIME-Version: 1.0 In-Reply-To: On Wed, Aug 28, 2024 at 12:32:53PM GMT, Alejandro Colomar wrote: > On Wed, Aug 28, 2024 at 11:03:19AM GMT, Yafang Shao wrote: > > These three functions follow the same pattern. To deduplicate the code, > > let's introduce a common helper __kmemdup_nul(). > >=20 > > Suggested-by: Andrew Morton > > Signed-off-by: Yafang Shao > > Cc: Simon Horman > > Cc: Matthew Wilcox > > Cc: Alejandro Colomar > > --- >=20 > Reviewed-by: Alejandro Colomar (Or maybe I should say Co-developed-by: Alejandro Colomar Signed-off-by: Alejandro Colomar ) >=20 > Cheers, > Alex >=20 > > mm/util.c | 68 ++++++++++++++++++++++--------------------------------- > > 1 file changed, 27 insertions(+), 41 deletions(-) > >=20 > > diff --git a/mm/util.c b/mm/util.c > > index 9a77a347c385..42714fe13e24 100644 > > --- a/mm/util.c > > +++ b/mm/util.c > > @@ -45,33 +45,41 @@ void kfree_const(const void *x) > > EXPORT_SYMBOL(kfree_const); > > =20 > > /** > > - * kstrdup - allocate space for and copy an existing string > > - * @s: the string to duplicate > > + * __kmemdup_nul - Create a NUL-terminated string from @s, which might= be unterminated. > > + * @s: The data to copy > > + * @len: The size of the data, not including the NUL terminator > > * @gfp: the GFP mask used in the kmalloc() call when allocating memory > > * > > - * Return: newly allocated copy of @s or %NULL in case of error > > + * Return: newly allocated copy of @s with NUL-termination or %NULL in > > + * case of error > > */ > > -noinline > > -char *kstrdup(const char *s, gfp_t gfp) > > +static __always_inline char *__kmemdup_nul(const char *s, size_t len, = gfp_t gfp) > > { > > - size_t len; > > char *buf; > > =20 > > - if (!s) > > + /* '+1' for the NUL terminator */ > > + buf =3D kmalloc_track_caller(len + 1, gfp); > > + if (!buf) > > return NULL; > > =20 > > - len =3D strlen(s) + 1; > > - buf =3D kmalloc_track_caller(len, gfp); > > - if (buf) { > > - memcpy(buf, s, len); > > - /* During memcpy(), the string might be updated to a new value, > > - * which could be longer than the string when strlen() is > > - * called. Therefore, we need to add a NUL termimator. > > - */ > > - buf[len - 1] =3D '\0'; > > - } > > + memcpy(buf, s, len); > > + /* Ensure the buf is always NUL-terminated, regardless of @s. */ > > + buf[len] =3D '\0'; > > return buf; > > } > > + > > +/** > > + * kstrdup - allocate space for and copy an existing string > > + * @s: the string to duplicate > > + * @gfp: the GFP mask used in the kmalloc() call when allocating memory > > + * > > + * Return: newly allocated copy of @s or %NULL in case of error > > + */ > > +noinline > > +char *kstrdup(const char *s, gfp_t gfp) > > +{ > > + return s ? __kmemdup_nul(s, strlen(s), gfp) : NULL; > > +} > > EXPORT_SYMBOL(kstrdup); > > =20 > > /** > > @@ -106,19 +114,7 @@ EXPORT_SYMBOL(kstrdup_const); > > */ > > char *kstrndup(const char *s, size_t max, gfp_t gfp) > > { > > - size_t len; > > - char *buf; > > - > > - if (!s) > > - return NULL; > > - > > - len =3D strnlen(s, max); > > - buf =3D kmalloc_track_caller(len+1, gfp); > > - if (buf) { > > - memcpy(buf, s, len); > > - buf[len] =3D '\0'; > > - } > > - return buf; > > + return s ? __kmemdup_nul(s, strnlen(s, max), gfp) : NULL; > > } > > EXPORT_SYMBOL(kstrndup); > > =20 > > @@ -192,17 +188,7 @@ EXPORT_SYMBOL(kvmemdup); > > */ > > char *kmemdup_nul(const char *s, size_t len, gfp_t gfp) > > { > > - char *buf; > > - > > - if (!s) > > - return NULL; > > - > > - buf =3D kmalloc_track_caller(len + 1, gfp); > > - if (buf) { > > - memcpy(buf, s, len); > > - buf[len] =3D '\0'; > > - } > > - return buf; > > + return s ? __kmemdup_nul(s, len, gfp) : NULL; > > } > > EXPORT_SYMBOL(kmemdup_nul); > > =20 > > --=20 > > 2.43.5 > >=20 >=20 > --=20 > --=20 --xaakvknay6p4srmg Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEE6jqH8KTroDDkXfJAnowa+77/2zIFAmbO/PoACgkQnowa+77/ 2zLPnw/6A+aBCutQmKak+5R0meV1Cxil2Ncoh02Vf0xc2uWghVz4ES9qrmIq3vsF s+1JFTqZm983+114HxnK1NGfs30MiLs9PSiFvqtK77V4LW4I6V+eSKfjCywWH3ep s+0O51nVwX4a6ys2pW6q1Jb1JNPSjZovOQi1OVe+TWTtpHJSdqvsiYoLyEK9b41L f0wj/lJ4R7XhNBo/9WqpOW73pOub4Lx+RQThi87449z+mpiaKsaFZIZSlLv0nEvH 9VNnxKYmTQOzE7kHiEUoVSL7sC0DTU+FIsw1nF7an9UmEpTcvCHmEKQHpPerKs1T EoGHKtPiLY3U23B5fw4zxheJaIAQCDFM73XwYGhtluwQToyS4nswC2sjYJXB0Tyy 8SrkG+Lubl3mMRHY/WlBBkBumKo9GYRbIiuVU2N/Xsn0AdNViOy7mQTGdeGmh9qz l0pU6qnyso0Bdeaum22hOW/SgHwU1zvy8LVZwYkaWjMpDkuJKM2W5rvA1MGnHisR DkXA953cx17eO33YRMFpuRthuA7X2/qNmEj3d6elhUP3x9ea9YLRl1PC9j0jIgRA PiZXrJuFNeQpp27Qz6k4PxWbBmPjzZyleFwGtvZ86qbaRzFWZo2gCQZrrPckac2X 6fs3M2nM+8tZ6ZaqFeEb+kMnIRB3fZo7I59kFr6OEmgHSZsWCGM= =+lO+ -----END PGP SIGNATURE----- --xaakvknay6p4srmg--