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![Linus Torvalds](/assets/img/avatar_default.png)
Here is the set of driver core and kernfs changes for 6.2-rc1. The "big" change in here is the addition of a new macro, container_of_const() that will preserve the "const-ness" of a pointer passed into it. The "problem" of the current container_of() macro is that if you pass in a "const *", out of it can comes a non-const pointer unless you specifically ask for it. For many usages, we want to preserve the "const" attribute by using the same call. For a specific example, this series changes the kobj_to_dev() macro to use it, allowing it to be used no matter what the const value is. This prevents every subsystem from having to declare 2 different individual macros (i.e. kobj_const_to_dev() and kobj_to_dev()) and having the compiler enforce the const value at build time, which having 2 macros would not do either. The driver for all of this have been discussions with the Rust kernel developers as to how to properly mark driver core, and kobject, objects as being "non-mutable". The changes to the kobject and driver core in this pull request are the result of that, as there are lots of paths where kobjects and device pointers are not modified at all, so marking them as "const" allows the compiler to enforce this. So, a nice side affect of the Rust development effort has been already to clean up the driver core code to be more obvious about object rules. All of this has been bike-shedded in quite a lot of detail on lkml with different names and implementations resulting in the tiny version we have in here, much better than my original proposal. Lots of subsystem maintainers have acked the changes as well. Other than this change, included in here are smaller stuff like: - kernfs fixes and updates to handle lock contention better - vmlinux.lds.h fixes and updates - sysfs and debugfs documentation updates - device property updates All of these have been in the linux-next tree for quite a while with no problems, OTHER than some merge issues with other trees that should be obvious when you hit them (block tree deletes a driver that this tree modifies, iommufd tree modifies code that this tree also touches). If there are merge problems with these trees, please let me know. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> -----BEGIN PGP SIGNATURE----- iG0EABECAC0WIQT0tgzFv3jCIUoxPcsxR9QN2y37KQUCY5wz3A8cZ3JlZ0Brcm9h aC5jb20ACgkQMUfUDdst+yks0ACeKYUlVgCsER8eYW+x18szFa2QTXgAn2h/VhZe 1Fp53boFaQkGBjl8mGF8 =v+FB -----END PGP SIGNATURE----- Merge tag 'driver-core-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core Pull driver core updates from Greg KH: "Here is the set of driver core and kernfs changes for 6.2-rc1. The "big" change in here is the addition of a new macro, container_of_const() that will preserve the "const-ness" of a pointer passed into it. The "problem" of the current container_of() macro is that if you pass in a "const *", out of it can comes a non-const pointer unless you specifically ask for it. For many usages, we want to preserve the "const" attribute by using the same call. For a specific example, this series changes the kobj_to_dev() macro to use it, allowing it to be used no matter what the const value is. This prevents every subsystem from having to declare 2 different individual macros (i.e. kobj_const_to_dev() and kobj_to_dev()) and having the compiler enforce the const value at build time, which having 2 macros would not do either. The driver for all of this have been discussions with the Rust kernel developers as to how to properly mark driver core, and kobject, objects as being "non-mutable". The changes to the kobject and driver core in this pull request are the result of that, as there are lots of paths where kobjects and device pointers are not modified at all, so marking them as "const" allows the compiler to enforce this. So, a nice side affect of the Rust development effort has been already to clean up the driver core code to be more obvious about object rules. All of this has been bike-shedded in quite a lot of detail on lkml with different names and implementations resulting in the tiny version we have in here, much better than my original proposal. Lots of subsystem maintainers have acked the changes as well. Other than this change, included in here are smaller stuff like: - kernfs fixes and updates to handle lock contention better - vmlinux.lds.h fixes and updates - sysfs and debugfs documentation updates - device property updates All of these have been in the linux-next tree for quite a while with no problems" * tag 'driver-core-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (58 commits) device property: Fix documentation for fwnode_get_next_parent() firmware_loader: fix up to_fw_sysfs() to preserve const usb.h: take advantage of container_of_const() device.h: move kobj_to_dev() to use container_of_const() container_of: add container_of_const() that preserves const-ness of the pointer driver core: fix up missed drivers/s390/char/hmcdrv_dev.c class.devnode() conversion. driver core: fix up missed scsi/cxlflash class.devnode() conversion. driver core: fix up some missing class.devnode() conversions. driver core: make struct class.devnode() take a const * driver core: make struct class.dev_uevent() take a const * cacheinfo: Remove of_node_put() for fw_token device property: Add a blank line in Kconfig of tests device property: Rename goto label to be more precise device property: Move PROPERTY_ENTRY_BOOL() a bit down device property: Get rid of __PROPERTY_ENTRY_ARRAY_EL*SIZE*() kernfs: fix all kernel-doc warnings and multiple typos driver core: pass a const * into of_device_uevent() kobject: kset_uevent_ops: make name() callback take a const * kobject: kset_uevent_ops: make filter() callback take a const * kobject: make kobject_namespace take a const * ...
192 lines
4.3 KiB
C
192 lines
4.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (c) 2019 Hammerspace Inc
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*/
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#include <linux/module.h>
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#include <linux/kobject.h>
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#include <linux/sysfs.h>
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#include <linux/fs.h>
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#include <linux/slab.h>
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#include <linux/netdevice.h>
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#include <linux/string.h>
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#include <linux/nfs_fs.h>
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#include <linux/rcupdate.h>
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#include "nfs4_fs.h"
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#include "netns.h"
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#include "sysfs.h"
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struct kobject *nfs_client_kobj;
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static struct kset *nfs_client_kset;
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static void nfs_netns_object_release(struct kobject *kobj)
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{
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kfree(kobj);
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}
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static const struct kobj_ns_type_operations *nfs_netns_object_child_ns_type(
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const struct kobject *kobj)
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{
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return &net_ns_type_operations;
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}
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static struct kobj_type nfs_netns_object_type = {
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.release = nfs_netns_object_release,
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.sysfs_ops = &kobj_sysfs_ops,
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.child_ns_type = nfs_netns_object_child_ns_type,
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};
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static struct kobject *nfs_netns_object_alloc(const char *name,
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struct kset *kset, struct kobject *parent)
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{
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struct kobject *kobj;
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kobj = kzalloc(sizeof(*kobj), GFP_KERNEL);
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if (kobj) {
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kobj->kset = kset;
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if (kobject_init_and_add(kobj, &nfs_netns_object_type,
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parent, "%s", name) == 0)
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return kobj;
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kobject_put(kobj);
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}
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return NULL;
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}
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int nfs_sysfs_init(void)
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{
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nfs_client_kset = kset_create_and_add("nfs", NULL, fs_kobj);
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if (!nfs_client_kset)
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return -ENOMEM;
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nfs_client_kobj = nfs_netns_object_alloc("net", nfs_client_kset, NULL);
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if (!nfs_client_kobj) {
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kset_unregister(nfs_client_kset);
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nfs_client_kset = NULL;
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return -ENOMEM;
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}
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return 0;
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}
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void nfs_sysfs_exit(void)
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{
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kobject_put(nfs_client_kobj);
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kset_unregister(nfs_client_kset);
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}
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static ssize_t nfs_netns_identifier_show(struct kobject *kobj,
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struct kobj_attribute *attr, char *buf)
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{
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struct nfs_netns_client *c = container_of(kobj,
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struct nfs_netns_client,
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kobject);
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ssize_t ret;
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rcu_read_lock();
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ret = sysfs_emit(buf, "%s\n", rcu_dereference(c->identifier));
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rcu_read_unlock();
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return ret;
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}
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/* Strip trailing '\n' */
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static size_t nfs_string_strip(const char *c, size_t len)
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{
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while (len > 0 && c[len-1] == '\n')
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--len;
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return len;
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}
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static ssize_t nfs_netns_identifier_store(struct kobject *kobj,
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struct kobj_attribute *attr,
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const char *buf, size_t count)
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{
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struct nfs_netns_client *c = container_of(kobj,
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struct nfs_netns_client,
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kobject);
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const char *old;
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char *p;
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size_t len;
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len = nfs_string_strip(buf, min_t(size_t, count, CONTAINER_ID_MAXLEN));
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if (!len)
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return 0;
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p = kmemdup_nul(buf, len, GFP_KERNEL);
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if (!p)
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return -ENOMEM;
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old = rcu_dereference_protected(xchg(&c->identifier, (char __rcu *)p), 1);
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if (old) {
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synchronize_rcu();
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kfree(old);
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}
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return count;
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}
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static void nfs_netns_client_release(struct kobject *kobj)
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{
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struct nfs_netns_client *c = container_of(kobj,
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struct nfs_netns_client,
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kobject);
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kfree(rcu_dereference_raw(c->identifier));
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kfree(c);
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}
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static const void *nfs_netns_client_namespace(const struct kobject *kobj)
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{
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return container_of(kobj, struct nfs_netns_client, kobject)->net;
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}
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static struct kobj_attribute nfs_netns_client_id = __ATTR(identifier,
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0644, nfs_netns_identifier_show, nfs_netns_identifier_store);
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static struct attribute *nfs_netns_client_attrs[] = {
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&nfs_netns_client_id.attr,
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NULL,
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};
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ATTRIBUTE_GROUPS(nfs_netns_client);
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static struct kobj_type nfs_netns_client_type = {
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.release = nfs_netns_client_release,
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.default_groups = nfs_netns_client_groups,
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.sysfs_ops = &kobj_sysfs_ops,
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.namespace = nfs_netns_client_namespace,
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};
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static struct nfs_netns_client *nfs_netns_client_alloc(struct kobject *parent,
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struct net *net)
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{
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struct nfs_netns_client *p;
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p = kzalloc(sizeof(*p), GFP_KERNEL);
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if (p) {
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p->net = net;
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p->kobject.kset = nfs_client_kset;
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if (kobject_init_and_add(&p->kobject, &nfs_netns_client_type,
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parent, "nfs_client") == 0)
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return p;
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kobject_put(&p->kobject);
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}
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return NULL;
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}
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void nfs_netns_sysfs_setup(struct nfs_net *netns, struct net *net)
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{
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struct nfs_netns_client *clp;
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clp = nfs_netns_client_alloc(nfs_client_kobj, net);
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if (clp) {
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netns->nfs_client = clp;
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kobject_uevent(&clp->kobject, KOBJ_ADD);
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}
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}
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void nfs_netns_sysfs_destroy(struct nfs_net *netns)
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{
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struct nfs_netns_client *clp = netns->nfs_client;
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if (clp) {
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kobject_uevent(&clp->kobject, KOBJ_REMOVE);
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kobject_del(&clp->kobject);
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kobject_put(&clp->kobject);
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netns->nfs_client = NULL;
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}
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}
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