[PATCH 2/9] sysctl: use ctl_header_cookie in proc_handler

From: Lucian Adrian Grijincu
Date: Fri Feb 25 2011 - 13:55:54 EST

TODO: if this patch series gets a positive feedback this patch will be
extended with a kernel-wide change of each proc_handler to add a
'cookie' argument.

Signed-off-by: Lucian Adrian Grijincu <lucian.grijincu@xxxxxxxxx>
fs/proc/proc_sysctl.c | 11 ++++++++++-
include/linux/sysctl.h | 3 +++
2 files changed, 13 insertions(+), 1 deletions(-)

diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index 09a1f92..85b6b75 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -135,6 +135,7 @@ static ssize_t proc_sys_call_handler(struct file *filp, void __user *buf,
struct inode *inode = filp->f_path.dentry->d_inode;
struct ctl_table_header *head = grab_header(inode);
struct ctl_table *table = PROC_I(inode)->sysctl_entry;
+ proc_handler_cookie *phc = (proc_handler_cookie *) table->proc_handler;
ssize_t error;
size_t res;

@@ -156,7 +157,15 @@ static ssize_t proc_sys_call_handler(struct file *filp, void __user *buf,

/* careful: calling conventions are nasty here */
res = count;
- error = table->proc_handler(table, write, buf, &res, ppos);
+ /*XXX Most handlers only use the first 5 arguments (without
+ *XXX @cookie). Changing all handlers is too much of work,
+ *XXX as this is only a RFC patch at the moment.
+ *XXX
+ *XXX This is just a HACK for now, I did this this way to not
+ *XXX waste time changing all the handlers, in the final version
+ *XXX I'll change all the handlers if there's not other solution.
+ */
+ error = phc(table, write, buf, &res, ppos, head->ctl_header_cookie);
if (!error)
error = res;
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index 43fed29..3d21832 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -963,6 +963,9 @@ typedef struct ctl_table ctl_table;

typedef int proc_handler (struct ctl_table *ctl, int write,
void __user *buffer, size_t *lenp, loff_t *ppos);
+typedef int proc_handler_cookie(struct ctl_table *ctl, int write,
+ void __user *buffer, size_t *lenp,
+ loff_t *ppos, void *ctl_header_cookie);

extern int proc_dostring(struct ctl_table *, int,
void __user *, size_t *, loff_t *);

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