> 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.
Reviewed-by: James Simmons <jsimm...@infradead.org>
> Signed-off-by: NeilBrown <ne...@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
>
>
>
