Return-Path: Received: from mail-qk0-f193.google.com ([209.85.220.193]:36150 "EHLO mail-qk0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752036AbdECQ4B (ORCPT ); Wed, 3 May 2017 12:56:01 -0400 Received: by mail-qk0-f193.google.com with SMTP id o4so3515246qkb.3 for ; Wed, 03 May 2017 09:56:01 -0700 (PDT) Message-ID: <1493830556.2699.7.camel@poochiereds.net> Subject: Re: [PATCH 1/9] Provide a function to create a NUL-terminated string from unterminated data From: Jeff Layton To: David Howells , viro@zeniv.linux.org.uk Cc: linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org, mszeredi@redhat.com Date: Wed, 03 May 2017 12:55:56 -0400 In-Reply-To: <149382748241.30481.12971647975706869540.stgit@warthog.procyon.org.uk> References: <149382747487.30481.15428192741961545429.stgit@warthog.procyon.org.uk> <149382748241.30481.12971647975706869540.stgit@warthog.procyon.org.uk> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Sender: linux-nfs-owner@vger.kernel.org List-ID: On Wed, 2017-05-03 at 17:04 +0100, David Howells wrote: > Provide a function, kstrcreate(), that will create a NUL-terminated string > from an unterminated character array where the length is known in advance. > > This is better than kstrndup() in situations where we already know the > string length as the strnlen() in kstrndup() is superfluous. > > Signed-off-by: David Howells > --- > > include/linux/string.h | 1 + > mm/util.c | 22 ++++++++++++++++++++++ > 2 files changed, 23 insertions(+) > > diff --git a/include/linux/string.h b/include/linux/string.h > index 26b6f6a66f83..5596ae56ce0a 100644 > --- a/include/linux/string.h > +++ b/include/linux/string.h > @@ -122,6 +122,7 @@ extern void kfree_const(const void *x); > extern char *kstrdup(const char *s, gfp_t gfp) __malloc; > extern const char *kstrdup_const(const char *s, gfp_t gfp); > extern char *kstrndup(const char *s, size_t len, gfp_t gfp); > +extern char *kstrcreate(const char *s, size_t len, gfp_t gfp); > extern void *kmemdup(const void *src, size_t len, gfp_t gfp); > > extern char **argv_split(gfp_t gfp, const char *str, int *argcp); > diff --git a/mm/util.c b/mm/util.c > index 656dc5e37a87..01887bbdb11e 100644 > --- a/mm/util.c > +++ b/mm/util.c > @@ -103,6 +103,28 @@ char *kstrndup(const char *s, size_t max, gfp_t gfp) > EXPORT_SYMBOL(kstrndup); > > /** > + * kstrcreate - Create a NUL-terminated string from unterminated data > + * @s: The data to stringify > + * @len: The size of the data > + * @gfp: the GFP mask used in the kmalloc() call when allocating memory > + */ > +char *kstrcreate(const char *s, size_t len, gfp_t gfp) > +{ > + char *buf; > + > + if (!s) > + return NULL; > + > + buf = kmalloc_track_caller(len + 1, gfp); > + if (buf) { > + memcpy(buf, s, len); > + buf[len] = '\0'; > + } > + return buf; > +} > +EXPORT_SYMBOL(kstrcreate); > + > +/** > * kmemdup - duplicate region of memory > * > * @src: memory region to duplicate > > I haven't gotten to the part where this gets used yet, but it looks like a nice helper. Reviewed-by: Jeff Layton