Return-Path: Received: from mail-pf0-f195.google.com ([209.85.192.195]:33162 "EHLO mail-pf0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753793AbdAECqJ (ORCPT ); Wed, 4 Jan 2017 21:46:09 -0500 Subject: Re: [PATCH v5 1/2] sysctl: introduce new proc handler proc_dobool To: Alexey Dobriyan References: <1481786661-973-1-git-send-email-hejianet@gmail.com> <1481786661-973-2-git-send-email-hejianet@gmail.com> <20170104210933.GB21562@fieldses.org> Cc: "J. Bruce Fields" , linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org, "Eric W. Biederman" , Andrew Morton , Dmitry Torokhov , Serge Hallyn , "David S. Miller" , 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 From: hejianet Message-ID: <1986753d-d7f7-120d-f6ec-011896b54849@gmail.com> Date: Thu, 5 Jan 2017 10:45:46 +0800 MIME-Version: 1.0 In-Reply-To: <20170104210933.GB21562@fieldses.org> Content-Type: text/plain; charset=windows-1252; format=flowed Sender: linux-nfs-owner@vger.kernel.org List-ID: On 05/01/2017 5:09 AM, J. Bruce Fields wrote: > 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? Hi Alexey, any thoughts? ;-) Thanks B.R. Jia > 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