staging: lustre: replace libcfs_register_ioctl with a blocking notifier_chain

libcfs allows other modules to register handlers for ioctls.
The implementation it uses for this is nearly identical to a
blocking notifier chain, so change to use that.

The biggest difference is that the return value from notifier has a
defined format, where libcfs_register_ioctl uses -EINVAL to mean
"continue".  This requires a little bit of conversion.

Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/lustre/include/linux/libcfs/libcfs.h b/drivers/staging/lustre/include/linux/libcfs/libcfs.h
index d9002e7424d45f0e3d3b05ce2eea406e560b6a74..63ea0e99ec582049aa2434091b90d92273b44cb1 100644 (file)
--- a/drivers/staging/lustre/include/linux/libcfs/libcfs.h
+++ b/drivers/staging/lustre/include/linux/libcfs/libcfs.h
@@ -93,19 +93,14 @@
 #define LNET_ACCEPTOR_MIN_RESERVED_PORT    512
 #define LNET_ACCEPTOR_MAX_RESERVED_PORT    1023
 
-struct libcfs_ioctl_handler {
-       struct list_head item;
-       int (*handle_ioctl)(unsigned int cmd, struct libcfs_ioctl_hdr *hdr);
-};
-
-#define DECLARE_IOCTL_HANDLER(ident, func)                     \
-       struct libcfs_ioctl_handler ident = {                   \
-               .item           = LIST_HEAD_INIT(ident.item),   \
-               .handle_ioctl   = func                          \
-       }
+extern struct blocking_notifier_head libcfs_ioctl_list;
+static inline int notifier_from_ioctl_errno(int err)
+{
+       if (err == -EINVAL)
+               return NOTIFY_OK;
+       return notifier_from_errno(err) | NOTIFY_STOP_MASK;
+}
 
-int libcfs_register_ioctl(struct libcfs_ioctl_handler *hand);
-int libcfs_deregister_ioctl(struct libcfs_ioctl_handler *hand);
 int libcfs_setup(void);
 
 #define _LIBCFS_H

diff --git a/drivers/staging/lustre/lnet/libcfs/module.c b/drivers/staging/lustre/lnet/libcfs/module.c
index 3e51aae751c557f7cebc88543ba774373cf91e83..b3a7c1a912ba7003ae71be9c4660199ab5c19e47 100644 (file)
--- a/drivers/staging/lustre/lnet/libcfs/module.c
+++ b/drivers/staging/lustre/lnet/libcfs/module.c
@@ -62,38 +62,8 @@
 
 static struct dentry *lnet_debugfs_root;
 
-static DECLARE_RWSEM(ioctl_list_sem);
-static LIST_HEAD(ioctl_list);
-
-int libcfs_register_ioctl(struct libcfs_ioctl_handler *hand)
-{
-       int rc = 0;
-
-       down_write(&ioctl_list_sem);
-       if (!list_empty(&hand->item))
-               rc = -EBUSY;
-       else
-               list_add_tail(&hand->item, &ioctl_list);
-       up_write(&ioctl_list_sem);
-
-       return rc;
-}
-EXPORT_SYMBOL(libcfs_register_ioctl);
-
-int libcfs_deregister_ioctl(struct libcfs_ioctl_handler *hand)
-{
-       int rc = 0;
-
-       down_write(&ioctl_list_sem);
-       if (list_empty(&hand->item))
-               rc = -ENOENT;
-       else
-               list_del_init(&hand->item);
-       up_write(&ioctl_list_sem);
-
-       return rc;
-}
-EXPORT_SYMBOL(libcfs_deregister_ioctl);
+BLOCKING_NOTIFIER_HEAD(libcfs_ioctl_list);
+EXPORT_SYMBOL(libcfs_ioctl_list);
 
 static inline size_t libcfs_ioctl_packlen(struct libcfs_ioctl_data *data)
 {
@@ -268,24 +238,18 @@ static int libcfs_ioctl(unsigned long cmd, void __user *uparam)
                libcfs_debug_mark_buffer(data->ioc_inlbuf1);
                break;
 
-       default: {
-               struct libcfs_ioctl_handler *hand;
-
-               err = -EINVAL;
-               down_read(&ioctl_list_sem);
-               list_for_each_entry(hand, &ioctl_list, item) {
-                       err = hand->handle_ioctl(cmd, hdr);
-                       if (err == -EINVAL)
-                               continue;
-
-                       if (!err) {
-                               if (copy_to_user(uparam, hdr, hdr->ioc_len))
-                                       err = -EFAULT;
-                       }
-                       break;
-               }
-               up_read(&ioctl_list_sem);
-               break; }
+       default:
+               err = blocking_notifier_call_chain(&libcfs_ioctl_list,
+                                                  cmd, hdr);
+               if (!(err & NOTIFY_STOP_MASK))
+                       /* No-one claimed the ioctl */
+                       err = -EINVAL;
+               else
+                       err = notifier_to_errno(err);
+               if (!err)
+                       if (copy_to_user(uparam, hdr, hdr->ioc_len))
+                               err = -EFAULT;
+               break;
        }
 out:
        kvfree(hdr);

diff --git a/drivers/staging/lustre/lnet/lnet/module.c b/drivers/staging/lustre/lnet/lnet/module.c
index f6e912e79ca7871dff594b0ff6e22a1cc626adc2..9d06664f0c1736306e4790bf032d70807e7499da 100644 (file)
--- a/drivers/staging/lustre/lnet/lnet/module.c
+++ b/drivers/staging/lustre/lnet/lnet/module.c
@@ -136,30 +136,37 @@ out_unlock:
 }
 
 static int
-lnet_ioctl(unsigned int cmd, struct libcfs_ioctl_hdr *hdr)
+lnet_ioctl(struct notifier_block *nb,
+          unsigned long cmd, void *vdata)
 {
        int rc;
+       struct libcfs_ioctl_hdr *hdr = vdata;
 
        switch (cmd) {
        case IOC_LIBCFS_CONFIGURE: {
                struct libcfs_ioctl_data *data =
                        (struct libcfs_ioctl_data *)hdr;
 
-               if (data->ioc_hdr.ioc_len < sizeof(*data))
-                       return -EINVAL;
-
-               the_lnet.ln_nis_from_mod_params = data->ioc_flags;
-               return lnet_configure(NULL);
+               if (data->ioc_hdr.ioc_len < sizeof(*data)) {
+                       rc = -EINVAL;
+               } else {
+                       the_lnet.ln_nis_from_mod_params = data->ioc_flags;
+                       rc = lnet_configure(NULL);
+               }
+               break;
        }
 
        case IOC_LIBCFS_UNCONFIGURE:
-               return lnet_unconfigure();
+               rc = lnet_unconfigure();
+               break;
 
        case IOC_LIBCFS_ADD_NET:
-               return lnet_dyn_configure(hdr);
+               rc = lnet_dyn_configure(hdr);
+               break;
 
        case IOC_LIBCFS_DEL_NET:
-               return lnet_dyn_unconfigure(hdr);
+               rc = lnet_dyn_unconfigure(hdr);
+               break;
 
        default:
                /*
@@ -172,11 +179,14 @@ lnet_ioctl(unsigned int cmd, struct libcfs_ioctl_hdr *hdr)
                        rc = LNetCtl(cmd, hdr);
                        LNetNIFini();
                }
-               return rc;
+               break;
        }
+       return notifier_from_ioctl_errno(rc);
 }
 
-static DECLARE_IOCTL_HANDLER(lnet_ioctl_handler, lnet_ioctl);
+static struct notifier_block lnet_ioctl_handler = {
+       .notifier_call = lnet_ioctl,
+};
 
 static int __init lnet_init(void)
 {
@@ -194,7 +204,8 @@ static int __init lnet_init(void)
                return rc;
        }
 
-       rc = libcfs_register_ioctl(&lnet_ioctl_handler);
+       rc = blocking_notifier_chain_register(&libcfs_ioctl_list,
+                                             &lnet_ioctl_handler);
        LASSERT(!rc);
 
        if (config_on_load) {
@@ -212,7 +223,8 @@ static void __exit lnet_exit(void)
 {
        int rc;
 
-       rc = libcfs_deregister_ioctl(&lnet_ioctl_handler);
+       rc = blocking_notifier_chain_unregister(&libcfs_ioctl_list,
+                                               &lnet_ioctl_handler);
        LASSERT(!rc);
 
        lnet_lib_exit();

diff --git a/drivers/staging/lustre/lnet/selftest/conctl.c b/drivers/staging/lustre/lnet/selftest/conctl.c
index a2d8092bdeb79b10ce3bd412dbb51bd748d670f8..f22b01e390d342042098f95f53d4e3cbab598d7c 100644 (file)
--- a/drivers/staging/lustre/lnet/selftest/conctl.c
+++ b/drivers/staging/lustre/lnet/selftest/conctl.c
@@ -680,32 +680,34 @@ out:
 }
 
 int
-lstcon_ioctl_entry(unsigned int cmd, struct libcfs_ioctl_hdr *hdr)
+lstcon_ioctl_entry(struct notifier_block *nb,
+                  unsigned long cmd, void *vdata)
 {
-       char *buf;
+       struct libcfs_ioctl_hdr *hdr = vdata;
+       char *buf = NULL;
        struct libcfs_ioctl_data *data;
        int opc;
-       int rc;
+       int rc = -EINVAL;
 
        if (cmd != IOC_LIBCFS_LNETST)
-               return -EINVAL;
+               goto err;
 
        data = container_of(hdr, struct libcfs_ioctl_data, ioc_hdr);
 
        opc = data->ioc_u32[0];
 
        if (data->ioc_plen1 > PAGE_SIZE)
-               return -EINVAL;
+               goto err;
 
        buf = kmalloc(data->ioc_plen1, GFP_KERNEL);
+       rc = -ENOMEM;
        if (!buf)
-               return -ENOMEM;
+               goto err;
 
        /* copy in parameter */
-       if (copy_from_user(buf, data->ioc_pbuf1, data->ioc_plen1)) {
-               kfree(buf);
-               return -EFAULT;
-       }
+       rc = -EFAULT;
+       if (copy_from_user(buf, data->ioc_pbuf1, data->ioc_plen1))
+               goto err;
 
        mutex_lock(&console_session.ses_mutex);
 
@@ -785,6 +787,7 @@ lstcon_ioctl_entry(unsigned int cmd, struct libcfs_ioctl_hdr *hdr)
                break;
        default:
                rc = -EINVAL;
+               goto out;
        }
 
        if (copy_to_user(data->ioc_pbuf2, &console_session.ses_trans_stat,
@@ -792,8 +795,8 @@ lstcon_ioctl_entry(unsigned int cmd, struct libcfs_ioctl_hdr *hdr)
                rc = -EFAULT;
 out:
        mutex_unlock(&console_session.ses_mutex);
-
+err:
        kfree(buf);
 
-       return rc;
+       return notifier_from_ioctl_errno(rc);
 }

diff --git a/drivers/staging/lustre/lnet/selftest/console.c b/drivers/staging/lustre/lnet/selftest/console.c
index 1889f1e8647385e0ac78e821ff51c0b4d5f9a12d..9fd6013354c64cfdf4b8152d108197ed764ab2b6 100644 (file)
--- a/drivers/staging/lustre/lnet/selftest/console.c
+++ b/drivers/staging/lustre/lnet/selftest/console.c
@@ -1996,7 +1996,9 @@ static void lstcon_init_acceptor_service(void)
        lstcon_acceptor_service.sv_wi_total = SFW_FRWK_WI_MAX;
 }
 
-static DECLARE_IOCTL_HANDLER(lstcon_ioctl_handler, lstcon_ioctl_entry);
+static struct notifier_block lstcon_ioctl_handler = {
+       .notifier_call = lstcon_ioctl_entry,
+};
 
 /* initialize console */
 int
@@ -2048,7 +2050,8 @@ lstcon_console_init(void)
                goto out;
        }
 
-       rc = libcfs_register_ioctl(&lstcon_ioctl_handler);
+       rc = blocking_notifier_chain_register(&libcfs_ioctl_list,
+                                             &lstcon_ioctl_handler);
 
        if (!rc) {
                lstcon_rpc_module_init();
@@ -2071,7 +2074,8 @@ lstcon_console_fini(void)
 {
        int i;
 
-       libcfs_deregister_ioctl(&lstcon_ioctl_handler);
+       blocking_notifier_chain_unregister(&libcfs_ioctl_list,
+                                          &lstcon_ioctl_handler);
 
        mutex_lock(&console_session.ses_mutex);
 

diff --git a/drivers/staging/lustre/lnet/selftest/console.h b/drivers/staging/lustre/lnet/selftest/console.h
index 3933ed4cca9372f5f8bc18eb275fb07871b0ceb1..d65b8d942bac60b1bc7812fce05d661ce3c709b9 100644 (file)
--- a/drivers/staging/lustre/lnet/selftest/console.h
+++ b/drivers/staging/lustre/lnet/selftest/console.h
@@ -187,7 +187,8 @@ lstcon_id2hash(struct lnet_process_id id, struct list_head *hash)
        return &hash[idx];
 }
 
-int lstcon_ioctl_entry(unsigned int cmd, struct libcfs_ioctl_hdr *hdr);
+int lstcon_ioctl_entry(struct notifier_block *nb,
+                      unsigned long cmd, void *vdata);
 int lstcon_console_init(void);
 int lstcon_console_fini(void);
 int lstcon_session_match(struct lst_sid sid);