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Subject[PATCH 07/11] staging: lustre: fold lprocfs_call_handler functionality into lnet_debugfs_*
The calling convention for ->proc_handler is rather clumsy,
as a comment in fs/procfs/proc_sysctl.c confirms.
lustre has copied this convention to lnet_debugfs_{read,write},
and then provided a wrapper for handlers - lprocfs_call_handler -
to work around the clumsiness.

It is cleaner to just fold the functionality of lprocfs_call_handler()
into lnet_debugfs_* and let them call the final handler directly.

If these files were ever moved to /proc/sys (which seems unlikely) the
handling in fs/procfs/proc_sysctl.c would need to be fixed to, but
that would not be a bad thing.

So modify all the functions that did use the wrapper to not need it
now that a more sane calling convention is available.

Signed-off-by: NeilBrown <neilb@suse.com>
---
.../staging/lustre/include/linux/libcfs/libcfs.h | 4 -
drivers/staging/lustre/lnet/libcfs/module.c | 84 +++++++-------------
drivers/staging/lustre/lnet/lnet/router_proc.c | 41 +++-------
3 files changed, 41 insertions(+), 88 deletions(-)

diff --git a/drivers/staging/lustre/include/linux/libcfs/libcfs.h b/drivers/staging/lustre/include/linux/libcfs/libcfs.h
index edc7ed0dcb94..7ac609328256 100644
--- a/drivers/staging/lustre/include/linux/libcfs/libcfs.h
+++ b/drivers/staging/lustre/include/linux/libcfs/libcfs.h
@@ -57,10 +57,6 @@ int libcfs_setup(void);
extern struct workqueue_struct *cfs_rehash_wq;

void lustre_insert_debugfs(struct ctl_table *table);
-int lprocfs_call_handler(void *data, int write, loff_t *ppos,
- void __user *buffer, size_t *lenp,
- int (*handler)(void *data, int write, loff_t pos,
- void __user *buffer, int len));

/*
* Memory
diff --git a/drivers/staging/lustre/lnet/libcfs/module.c b/drivers/staging/lustre/lnet/libcfs/module.c
index 5dc7de9e6478..02c404c6738e 100644
--- a/drivers/staging/lustre/lnet/libcfs/module.c
+++ b/drivers/staging/lustre/lnet/libcfs/module.c
@@ -290,33 +290,15 @@ static struct miscdevice libcfs_dev = {

static int libcfs_dev_registered;

-int lprocfs_call_handler(void *data, int write, loff_t *ppos,
- void __user *buffer, size_t *lenp,
- int (*handler)(void *data, int write, loff_t pos,
- void __user *buffer, int len))
-{
- int rc = handler(data, write, *ppos, buffer, *lenp);
-
- if (rc < 0)
- return rc;
-
- if (write) {
- *ppos += *lenp;
- } else {
- *lenp = rc;
- *ppos += rc;
- }
- return 0;
-}
-EXPORT_SYMBOL(lprocfs_call_handler);
-
-static int __proc_dobitmasks(void *data, int write,
- loff_t pos, void __user *buffer, int nob)
+static int proc_dobitmasks(struct ctl_table *table, int write,
+ void __user *buffer, size_t *lenp, loff_t *ppos)
{
const int tmpstrlen = 512;
char *tmpstr;
int rc;
- unsigned int *mask = data;
+ size_t nob = *lenp;
+ loff_t pos = *ppos;
+ unsigned int *mask = table->data;
int is_subsys = (mask == &libcfs_subsystem_debug) ? 1 : 0;
int is_printk = (mask == &libcfs_printk) ? 1 : 0;

@@ -351,32 +333,23 @@ static int __proc_dobitmasks(void *data, int write,
return rc;
}

-static int proc_dobitmasks(struct ctl_table *table, int write,
- void __user *buffer, size_t *lenp, loff_t *ppos)
+static int proc_dump_kernel(struct ctl_table *table, int write,
+ void __user *buffer, size_t *lenp, loff_t *ppos)
{
- return lprocfs_call_handler(table->data, write, ppos, buffer, lenp,
- __proc_dobitmasks);
-}
+ size_t nob = *lenp;

-static int __proc_dump_kernel(void *data, int write,
- loff_t pos, void __user *buffer, int nob)
-{
if (!write)
return 0;

return cfs_trace_dump_debug_buffer_usrstr(buffer, nob);
}

-static int proc_dump_kernel(struct ctl_table *table, int write,
+static int proc_daemon_file(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos)
{
- return lprocfs_call_handler(table->data, write, ppos, buffer, lenp,
- __proc_dump_kernel);
-}
+ size_t nob = *lenp;
+ loff_t pos = *ppos;

-static int __proc_daemon_file(void *data, int write,
- loff_t pos, void __user *buffer, int nob)
-{
if (!write) {
int len = strlen(cfs_tracefile);

@@ -390,13 +363,6 @@ static int __proc_daemon_file(void *data, int write,
return cfs_trace_daemon_command_usrstr(buffer, nob);
}

-static int proc_daemon_file(struct ctl_table *table, int write,
- void __user *buffer, size_t *lenp, loff_t *ppos)
-{
- return lprocfs_call_handler(table->data, write, ppos, buffer, lenp,
- __proc_daemon_file);
-}
-
static int libcfs_force_lbug(struct ctl_table *table, int write,
void __user *buffer,
size_t *lenp, loff_t *ppos)
@@ -419,9 +385,11 @@ static int proc_fail_loc(struct ctl_table *table, int write,
return rc;
}

-static int __proc_cpt_table(void *data, int write,
- loff_t pos, void __user *buffer, int nob)
+static int proc_cpt_table(struct ctl_table *table, int write,
+ void __user *buffer, size_t *lenp, loff_t *ppos)
{
+ size_t nob = *lenp;
+ loff_t pos = *ppos;
char *buf = NULL;
int len = 4096;
int rc = 0;
@@ -457,13 +425,6 @@ static int __proc_cpt_table(void *data, int write,
return rc;
}

-static int proc_cpt_table(struct ctl_table *table, int write,
- void __user *buffer, size_t *lenp, loff_t *ppos)
-{
- return lprocfs_call_handler(table->data, write, ppos, buffer, lenp,
- __proc_cpt_table);
-}
-
static struct ctl_table lnet_table[] = {
{
.procname = "debug",
@@ -573,10 +534,17 @@ static ssize_t lnet_debugfs_read(struct file *filp, char __user *buf,
{
struct ctl_table *table = filp->private_data;
int error;
+ loff_t old_pos = *ppos;

error = table->proc_handler(table, 0, (void __user *)buf, &count, ppos);
- if (!error)
+ /*
+ * On success, the length read is either in error or in count.
+ * If ppos changed, then use count, else use error
+ */
+ if (!error && *ppos != old_pos)
error = count;
+ else if (error > 0)
+ *ppos += error;

return error;
}
@@ -586,10 +554,14 @@ static ssize_t lnet_debugfs_write(struct file *filp, const char __user *buf,
{
struct ctl_table *table = filp->private_data;
int error;
+ loff_t old_pos = *ppos;

error = table->proc_handler(table, 1, (void __user *)buf, &count, ppos);
- if (!error)
+ if (!error) {
error = count;
+ if (*ppos == old_pos)
+ *ppos += count;
+ }

return error;
}
diff --git a/drivers/staging/lustre/lnet/lnet/router_proc.c b/drivers/staging/lustre/lnet/lnet/router_proc.c
index ae4b7f5953a0..f135082fec5c 100644
--- a/drivers/staging/lustre/lnet/lnet/router_proc.c
+++ b/drivers/staging/lustre/lnet/lnet/router_proc.c
@@ -74,11 +74,13 @@

#define LNET_PROC_VERSION(v) ((unsigned int)((v) & LNET_PROC_VER_MASK))

-static int __proc_lnet_stats(void *data, int write,
- loff_t pos, void __user *buffer, int nob)
+static int proc_lnet_stats(struct ctl_table *table, int write,
+ void __user *buffer, size_t *lenp, loff_t *ppos)
{
int rc;
struct lnet_counters *ctrs;
+ size_t nob = *lenp;
+ loff_t pos = *ppos;
int len;
char *tmpstr;
const int tmpsiz = 256; /* 7 %u and 4 %llu */
@@ -122,13 +124,6 @@ static int __proc_lnet_stats(void *data, int write,
return rc;
}

-static int proc_lnet_stats(struct ctl_table *table, int write,
- void __user *buffer, size_t *lenp, loff_t *ppos)
-{
- return lprocfs_call_handler(table->data, write, ppos, buffer, lenp,
- __proc_lnet_stats);
-}
-
static int proc_lnet_routes(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos)
{
@@ -562,9 +557,11 @@ static int proc_lnet_peers(struct ctl_table *table, int write,
return rc;
}

-static int __proc_lnet_buffers(void *data, int write,
- loff_t pos, void __user *buffer, int nob)
+static int proc_lnet_buffers(struct ctl_table *table, int write,
+ void __user *buffer, size_t *lenp, loff_t *ppos)
{
+ size_t nob = *lenp;
+ loff_t pos = *ppos;
char *s;
char *tmpstr;
int tmpsiz;
@@ -620,13 +617,6 @@ static int __proc_lnet_buffers(void *data, int write,
return rc;
}

-static int proc_lnet_buffers(struct ctl_table *table, int write,
- void __user *buffer, size_t *lenp, loff_t *ppos)
-{
- return lprocfs_call_handler(table->data, write, ppos, buffer, lenp,
- __proc_lnet_buffers);
-}
-
static int proc_lnet_nis(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos)
{
@@ -784,10 +774,13 @@ static struct lnet_portal_rotors portal_rotors[] = {
},
};

-static int __proc_lnet_portal_rotor(void *data, int write,
- loff_t pos, void __user *buffer, int nob)
+static int proc_lnet_portal_rotor(struct ctl_table *table, int write,
+ void __user *buffer, size_t *lenp,
+ loff_t *ppos)
{
const int buf_len = 128;
+ size_t nob = *lenp;
+ loff_t pos = *ppos;
char *buf;
char *tmp;
int rc;
@@ -845,14 +838,6 @@ static int __proc_lnet_portal_rotor(void *data, int write,
return rc;
}

-static int proc_lnet_portal_rotor(struct ctl_table *table, int write,
- void __user *buffer, size_t *lenp,
- loff_t *ppos)
-{
- return lprocfs_call_handler(table->data, write, ppos, buffer, lenp,
- __proc_lnet_portal_rotor);
-}
-
static struct ctl_table lnet_table[] = {
/*
* NB No .strategy entries have been provided since sysctl(8) prefers

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