Return-Path: Received: from fieldses.org ([173.255.197.46]:54408 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S937320AbdADVJp (ORCPT ); Wed, 4 Jan 2017 16:09:45 -0500 Date: Wed, 4 Jan 2017 16:09:33 -0500 From: "J. Bruce Fields" To: Jia He Cc: linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org, "Eric W. Biederman" , Andrew Morton , Dmitry Torokhov , Serge Hallyn , "David S. Miller" , Alexey Dobriyan , Subash Abhinov Kasiviswanathan , Arnaldo Carvalho de Melo , Al Viro , Mel Gorman , Kees Cook , Hugh Dickins , Daniel Bristot de Oliveira , Daniel Cashman , Arnd Bergmann , Jeff Layton , Trond Myklebust , Anna Schumaker Subject: Re: [PATCH v5 1/2] sysctl: introduce new proc handler proc_dobool Message-ID: <20170104210933.GB21562@fieldses.org> References: <1481786661-973-1-git-send-email-hejianet@gmail.com> <1481786661-973-2-git-send-email-hejianet@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1481786661-973-2-git-send-email-hejianet@gmail.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Thu, Dec 15, 2016 at 03:24:20PM +0800, Jia He wrote: > This is to let bool variable could be correctly displayed in > big/little endian sysctl procfs. sizeof(bool) is arch dependent, > proc_dobool should work in all arches. Did Alexey Debriyan agree that this dealt with his objections? Also it'd be nice to have a sign-off from somebody that's actually touched sysctl.c. Then I could take it through the nfsd tree if that doesn't cause anyone trouble. --b. > > Suggested-by: Pan Xinhui > Signed-off-by: Jia He > --- > include/linux/sysctl.h | 2 ++ > kernel/sysctl.c | 41 +++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 43 insertions(+) > > diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h > index adf4e51..255a9c7 100644 > --- a/include/linux/sysctl.h > +++ b/include/linux/sysctl.h > @@ -41,6 +41,8 @@ typedef int proc_handler (struct ctl_table *ctl, int write, > > extern int proc_dostring(struct ctl_table *, int, > void __user *, size_t *, loff_t *); > +extern int proc_dobool(struct ctl_table *, int, > + void __user *, size_t *, loff_t *); > extern int proc_dointvec(struct ctl_table *, int, > void __user *, size_t *, loff_t *); > extern int proc_douintvec(struct ctl_table *, int, > diff --git a/kernel/sysctl.c b/kernel/sysctl.c > index 706309f..c4bec65 100644 > --- a/kernel/sysctl.c > +++ b/kernel/sysctl.c > @@ -2112,6 +2112,20 @@ static int proc_put_char(void __user **buf, size_t *size, char c) > return 0; > } > > +static int do_proc_dobool_conv(bool *negp, unsigned long *lvalp, > + int *valp, > + int write, void *data) > +{ > + if (write) > + *(bool *)valp = *lvalp; > + else { > + int val = *(bool *)valp; > + > + *lvalp = (unsigned long)val; > + } > + return 0; > +} > + > static int do_proc_dointvec_conv(bool *negp, unsigned long *lvalp, > int *valp, > int write, void *data) > @@ -2258,6 +2272,26 @@ static int do_proc_dointvec(struct ctl_table *table, int write, > } > > /** > + * proc_dobool - read/write a bool > + * @table: the sysctl table > + * @write: %TRUE if this is a write to the sysctl file > + * @buffer: the user buffer > + * @lenp: the size of the user buffer > + * @ppos: file position > + * > + * Reads/writes up to table->maxlen/sizeof(unsigned int) integer > + * values from/to the user buffer, treated as an ASCII string. > + * > + * Returns 0 on success. > + */ > +int proc_dobool(struct ctl_table *table, int write, > + void __user *buffer, size_t *lenp, loff_t *ppos) > +{ > + return do_proc_dointvec(table, write, buffer, lenp, ppos, > + do_proc_dobool_conv, NULL); > +} > + > +/** > * proc_dointvec - read a vector of integers > * @table: the sysctl table > * @write: %TRUE if this is a write to the sysctl file > @@ -2885,6 +2919,12 @@ int proc_dostring(struct ctl_table *table, int write, > return -ENOSYS; > } > > +int proc_dobool(struct ctl_table *table, int write, > + void __user *buffer, size_t *lenp, loff_t *ppos) > +{ > + return -ENOSYS; > +} > + > int proc_dointvec(struct ctl_table *table, int write, > void __user *buffer, size_t *lenp, loff_t *ppos) > { > @@ -2941,6 +2981,7 @@ int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int write, > * No sense putting this after each symbol definition, twice, > * exception granted :-) > */ > +EXPORT_SYMBOL(proc_dobool); > EXPORT_SYMBOL(proc_dointvec); > EXPORT_SYMBOL(proc_douintvec); > EXPORT_SYMBOL(proc_dointvec_jiffies); > -- > 2.5.5