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Violators will be prosecuted for from ; Mon, 27 Aug 2018 11:34:03 +0100 Date: Mon, 27 Aug 2018 13:33:53 +0300 From: Mike Rapoport Subject: Re: [PATCH 1/2] devres: provide devm_kstrdup_const() References: <20180827082101.5036-1-brgl@bgdev.pl> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180827082101.5036-1-brgl@bgdev.pl> Message-Id: <20180827103353.GB13848@rapoport-lnx> Sender: owner-linux-mm@kvack.org List-ID: To: Bartosz Golaszewski Cc: Michael Turquette , Stephen Boyd , Greg Kroah-Hartman , "Rafael J . Wysocki" , Arend van Spriel , Ulf Hansson , Bjorn Helgaas , Vivek Gautam , Robin Murphy , Joe Perches , Heikki Krogerus , Andrew Morton , Michal Hocko , Al Viro , Jonathan Corbet , Roman Gushchin , Huang Ying , Kees Cook , Bjorn Andersson , linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org On Mon, Aug 27, 2018 at 10:21:00AM +0200, Bartosz Golaszewski wrote: > Provide a resource managed version of kstrdup_const(). This variant > internally calls devm_kstrdup() on pointers that are outside of > .rodata section. Also provide a corresponding version of devm_kfree(). > > Signed-off-by: Bartosz Golaszewski > --- > include/linux/device.h | 2 ++ > mm/util.c | 35 +++++++++++++++++++++++++++++++++++ > 2 files changed, 37 insertions(+) > > diff --git a/include/linux/device.h b/include/linux/device.h > index 8f882549edee..f8f5982d26b2 100644 > --- a/include/linux/device.h > +++ b/include/linux/device.h > @@ -693,7 +693,9 @@ static inline void *devm_kcalloc(struct device *dev, > return devm_kmalloc_array(dev, n, size, flags | __GFP_ZERO); > } > extern void devm_kfree(struct device *dev, void *p); > +extern void devm_kfree_const(struct device *dev, void *p); > extern char *devm_kstrdup(struct device *dev, const char *s, gfp_t gfp) __malloc; > +extern char *devm_kstrdup_const(struct device *dev, const char *s, gfp_t gfp); > extern void *devm_kmemdup(struct device *dev, const void *src, size_t len, > gfp_t gfp); > > diff --git a/mm/util.c b/mm/util.c > index d2890a407332..6d1f41b5775e 100644 > --- a/mm/util.c > +++ b/mm/util.c > @@ -39,6 +39,20 @@ void kfree_const(const void *x) > } > EXPORT_SYMBOL(kfree_const); > > +/** > + * devm_kfree_const - Resource managed conditional kfree > + * @dev: device this memory belongs to > + * @p: memory to free > + * > + * Function calls devm_kfree only if @p is not in .rodata section. > + */ > +void devm_kfree_const(struct device *dev, void *p) > +{ > + if (!is_kernel_rodata((unsigned long)p)) > + devm_kfree(dev, p); > +} > +EXPORT_SYMBOL(devm_kfree_const); > + > /** > * kstrdup - allocate space for and copy an existing string > * @s: the string to duplicate > @@ -78,6 +92,27 @@ const char *kstrdup_const(const char *s, gfp_t gfp) > } > EXPORT_SYMBOL(kstrdup_const); > > +/** > + * devm_kstrdup_const - resource managed conditional string duplication > + * @dev: device for which to duplicate the string > + * @s: the string to duplicate > + * @gfp: the GFP mask used in the kmalloc() call when allocating memory > + * > + * Function returns source string if it is in .rodata section otherwise it > + * fallbacks to devm_kstrdup. Please make it proper "Returns:" description and move to the end of the comment. See Documentation/doc-guide/kernel-doc.rst. > + * Strings allocated by devm_kstrdup_const will be automatically freed when > + * the associated device is detached. > + */ > +char *devm_kstrdup_const(struct device *dev, const char *s, gfp_t gfp) > +{ > + if (is_kernel_rodata((unsigned long)s)) > + return s; > + > + return devm_kstrdup(dev, s, gfp); > +} > +EXPORT_SYMBOL(devm_kstrdup_const); > + The devm_ variants seem to belong to drivers/base/devres.c rather than mm/util.c > /** > * kstrndup - allocate space for and copy an existing string > * @s: the string to duplicate > -- > 2.18.0 > -- Sincerely yours, Mike.