linux-kernel - [PATCH 2/7] pipe, sysctl: remove pipe_proc

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Date:   Sun,  7 Jan 2018 21:35:37 -0800
From:   Eric Biggers <ebiggers3@...il.com>
To:     linux-fsdevel@...r.kernel.org
Cc:     Alexander Viro <viro@...iv.linux.org.uk>,
        Joe Lawrence <joe.lawrence@...hat.com>,
        Michael Kerrisk <mtk.manpages@...il.com>,
        Willy Tarreau <w@....eu>,
        Mikulas Patocka <mpatocka@...hat.com>,
        "Luis R . Rodriguez" <mcgrof@...nel.org>,
        Kees Cook <keescook@...omium.org>,
        linux-kernel@...r.kernel.org, Eric Biggers <ebiggers@...gle.com>
Subject: [PATCH 2/7] pipe, sysctl: remove pipe_proc_fn()

From: Eric Biggers <ebiggers@...gle.com>

pipe_proc_fn() is no longer needed, as it only calls through to
proc_dopipe_max_size().  Just put proc_dopipe_max_size() in the
ctl_table entry directly, and remove the unneeded EXPORT_SYMBOL() and
the ENOSYS stub for it.

(The reason the ENOSYS stub isn't needed is that the pipe-max-size
ctl_table entry is located directly in 'kern_table' rather than being
registered separately.  Therefore, the entry is already only defined
when the kernel is built with sysctl support.)

Signed-off-by: Eric Biggers <ebiggers@...gle.com>
---
 fs/pipe.c                 | 10 ----------
 include/linux/pipe_fs_i.h |  1 -
 include/linux/sysctl.h    |  3 ---
 kernel/sysctl.c           | 15 +++++----------
 4 files changed, 5 insertions(+), 24 deletions(-)

diff --git a/fs/pipe.c b/fs/pipe.c
index a75f5d2ca99c..d0dec5e7ef33 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -1120,16 +1120,6 @@ static long pipe_set_size(struct pipe_inode_info *pipe, unsigned long arg)
 	return ret;
 }
 
-/*
- * This should work even if CONFIG_PROC_FS isn't set, as proc_dopipe_max_size
- * will return an error.
- */
-int pipe_proc_fn(struct ctl_table *table, int write, void __user *buf,
-		 size_t *lenp, loff_t *ppos)
-{
-	return proc_dopipe_max_size(table, write, buf, lenp, ppos);
-}
-
 /*
  * After the inode slimming patch, i_pipe/i_bdev/i_cdev share the same
  * location, so checking ->i_pipe is not enough to verify that this is a
diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h
index 7d9beda14584..5028bd4b2c96 100644
--- a/include/linux/pipe_fs_i.h
+++ b/include/linux/pipe_fs_i.h
@@ -170,7 +170,6 @@ void pipe_double_lock(struct pipe_inode_info *, struct pipe_inode_info *);
 extern unsigned int pipe_max_size;
 extern unsigned long pipe_user_pages_hard;
 extern unsigned long pipe_user_pages_soft;
-int pipe_proc_fn(struct ctl_table *, int, void __user *, size_t *, loff_t *);
 
 /* Drop the inode semaphore and wait for a pipe event, atomically */
 void pipe_wait(struct pipe_inode_info *pipe);
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index 992bc9948232..b769ecfcc3bd 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -51,9 +51,6 @@ extern int proc_dointvec_minmax(struct ctl_table *, int,
 extern int proc_douintvec_minmax(struct ctl_table *table, int write,
 				 void __user *buffer, size_t *lenp,
 				 loff_t *ppos);
-extern int proc_dopipe_max_size(struct ctl_table *table, int write,
-				void __user *buffer, size_t *lenp,
-				loff_t *ppos);
 extern int proc_dointvec_jiffies(struct ctl_table *, int,
 				 void __user *, size_t *, loff_t *);
 extern int proc_dointvec_userhz_jiffies(struct ctl_table *, int,
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index a71ebb5c5182..33e2f0f02000 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -218,6 +218,8 @@ static int proc_dointvec_minmax_coredump(struct ctl_table *table, int write,
 static int proc_dostring_coredump(struct ctl_table *table, int write,
 		void __user *buffer, size_t *lenp, loff_t *ppos);
 #endif
+static int proc_dopipe_max_size(struct ctl_table *table, int write,
+		void __user *buffer, size_t *lenp, loff_t *ppos);
 
 #ifdef CONFIG_MAGIC_SYSRQ
 /* Note: sysrq code uses it's own private copy */
@@ -1819,7 +1821,7 @@ static struct ctl_table fs_table[] = {
 		.data		= &pipe_max_size,
 		.maxlen		= sizeof(pipe_max_size),
 		.mode		= 0644,
-		.proc_handler	= &pipe_proc_fn,
+		.proc_handler	= proc_dopipe_max_size,
 	},
 	{
 		.procname	= "pipe-user-pages-hard",
@@ -2644,8 +2646,8 @@ static int do_proc_dopipe_max_size_conv(unsigned long *lvalp,
 	return 0;
 }
 
-int proc_dopipe_max_size(struct ctl_table *table, int write,
-			 void __user *buffer, size_t *lenp, loff_t *ppos)
+static int proc_dopipe_max_size(struct ctl_table *table, int write,
+				void __user *buffer, size_t *lenp, loff_t *ppos)
 {
 	return do_proc_douintvec(table, write, buffer, lenp, ppos,
 				 do_proc_dopipe_max_size_conv, NULL);
@@ -3154,12 +3156,6 @@ int proc_douintvec_minmax(struct ctl_table *table, int write,
 	return -ENOSYS;
 }
 
-int proc_dopipe_max_size(struct ctl_table *table, int write,
-			 void __user *buffer, size_t *lenp, loff_t *ppos)
-{
-	return -ENOSYS;
-}
-
 int proc_dointvec_jiffies(struct ctl_table *table, int write,
 		    void __user *buffer, size_t *lenp, loff_t *ppos)
 {
@@ -3203,7 +3199,6 @@ EXPORT_SYMBOL(proc_douintvec);
 EXPORT_SYMBOL(proc_dointvec_jiffies);
 EXPORT_SYMBOL(proc_dointvec_minmax);
 EXPORT_SYMBOL_GPL(proc_douintvec_minmax);
-EXPORT_SYMBOL_GPL(proc_dopipe_max_size);
 EXPORT_SYMBOL(proc_dointvec_userhz_jiffies);
 EXPORT_SYMBOL(proc_dointvec_ms_jiffies);
 EXPORT_SYMBOL(proc_dostring);
-- 
2.15.1