user/sven/linux.git/include/linux/debugfs.h, branch v5.4.215

debugfs: add debugfs_lookup_and_remove()

2022-09-15T10:04:54Z

commit dec9b2f1e0455a151a7293c367da22ab973f713e upstream. There is a very common pattern of using debugfs_remove(debufs_lookup(..)) which results in a dentry leak of the dentry that was looked up. Instead of having to open-code the correct pattern of calling dput() on the dentry, create debugfs_lookup_and_remove() to handle this pattern automatically and properly without any memory leaks. Cc: stable Reported-by: Kuyo Chang Tested-by: Kuyo Chang Link: https://lore.kernel.org/r/YxIaQ8cSinDR881k@kroah.com Signed-off-by: Greg Kroah-Hartman

debugfs: Fix !DEBUG_FS debugfs_create_automount

2020-10-01T11:17:21Z

[ Upstream commit 4250b047039d324e0ff65267c8beb5bad5052a86 ] If DEBUG_FS=n, compile fails with the following error: kernel/trace/trace.c: In function 'tracing_init_dentry': kernel/trace/trace.c:8658:9: error: passing argument 3 of 'debugfs_create_automount' from incompatible pointer type [-Werror=incompatible-pointer-types] 8658 | trace_automount, NULL); | ^~~~~~~~~~~~~~~ | | | struct vfsmount * (*)(struct dentry *, void *) In file included from kernel/trace/trace.c:24: ./include/linux/debugfs.h:206:25: note: expected 'struct vfsmount * (*)(void *)' but argument is of type 'struct vfsmount * (*)(struct dentry *, void *)' 206 | struct vfsmount *(*f)(void *), | ~~~~~~~~~~~~~~~~~~~^~~~~~~~~~ Signed-off-by: Kusanagi Kouichi Link: https://lore.kernel.org/r/20191121102021787.MLMY.25002.ppp.dion.ne.jp@dmta0003.auone-net.jp Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

debugfs: make debugfs_create_u32_array() return void

2019-06-03T14:34:27Z

The single user of debugfs_create_u32_array() does not care about the return value of it, so make it return void as there is no need to do anything with the return value. Signed-off-by: Greg Kroah-Hartman

debugfs: fix debugfs_real_fops() build error

2017-11-28T14:24:02Z

Some drivers use debugfs_real_fops() even when CONFIG_DEBUG_FS is disabled, which now leads to a build error: In file included from include/linux/list.h:9:0, from include/linux/wait.h:7, from include/linux/wait_bit.h:8, from include/linux/fs.h:6, from drivers/net/wireless/broadcom/b43legacy/debugfs.c:26: drivers/net/wireless/broadcom/b43legacy/debugfs.c: In function 'b43legacy_debugfs_read': drivers/net/wireless/broadcom/b43legacy/debugfs.c:224:23: error: implicit declaration of function 'debugfs_real_fops'; did you mean 'debugfs_create_bool'? [-Werror=implicit-function-declaration] My first impulse was to add another 'static inline' dummy function returning NULL for it, which would work fine. However, most callers feed the pointer into container_of(), so it seems a little dangerous here. Since all the callers are inside of a read/write file operation that gets eliminated in this configuration, so having an 'extern' declaration seems better here. If it ever gets used in a dangerous way, that will now result in a link error. Fixes: 7c8d469877b1 ("debugfs: add support for more elaborate ->d_fsdata") Cc: Jakub Kicinski Cc: Simon Horman Signed-off-by: Arnd Bergmann Signed-off-by: Greg Kroah-Hartman

debugfs: Remove redundant license text

2017-11-07T19:25:03Z

Now that the SPDX tag is in all debugfs files, that identifies the license in a specific and legally-defined manner. So the extra GPL text wording can be removed as it is no longer needed at all. This is done on a quest to remove the 700+ different ways that files in the kernel describe the GPL license text. And there's unneeded stuff like the address (sometimes incorrect) for the FSF which is never needed. No copyright headers or other non-license-description text was removed. Cc: Nicolai Stange Signed-off-by: Greg Kroah-Hartman

debugfs: add SPDX identifiers to all debugfs files

2017-11-07T19:25:03Z

It's good to have SPDX identifiers in all files to make it easier to audit the kernel tree for correct licenses. Update the debugfs files files with the correct SPDX license identifier based on the license text in the file itself. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This work is based on a script and data from Thomas Gleixner, Philippe Ombredanne, and Kate Stewart. Cc: Thomas Gleixner Cc: Kate Stewart Cc: Philippe Ombredanne Cc: Nicolai Stange Signed-off-by: Greg Kroah-Hartman

debugfs: purge obsolete SRCU based removal protection

2017-11-07T19:25:02Z

Purge the SRCU based file removal race protection in favour of the new, refcount based debugfs_file_get()/debugfs_file_put() API. Fixes: 49d200deaa68 ("debugfs: prevent access to removed files' private data") Signed-off-by: Nicolai Stange Signed-off-by: Greg Kroah-Hartman

debugfs: debugfs_real_fops(): drop __must_hold sparse annotation

2017-11-07T19:25:02Z

Currently, debugfs_real_fops() is annotated with a __must_hold(&debugfs_srcu) sparse annotation. With the conversion of the SRCU based protection of users against concurrent file removals to a per-file refcount based scheme, this becomes wrong. Drop this annotation. Signed-off-by: Nicolai Stange Signed-off-by: Greg Kroah-Hartman

debugfs: implement per-file removal protection

2017-11-07T19:25:02Z

Since commit 49d200deaa68 ("debugfs: prevent access to removed files' private data"), accesses to a file's private data are protected from concurrent removal by covering all file_operations with a SRCU read section and sychronizing with those before returning from debugfs_remove() by means of synchronize_srcu(). As pointed out by Johannes Berg, there are debugfs files with forever blocking file_operations. Their corresponding SRCU read side sections would block any debugfs_remove() forever as well, even unrelated ones. This results in a livelock. Because a remover can't cancel any indefinite blocking within foreign files, this is a problem. Resolve this by introducing support for more granular protection on a per-file basis. This is implemented by introducing an 'active_users' refcount_t to the per-file struct debugfs_fsdata state. At file creation time, it is set to one and a debugfs_remove() will drop that initial reference. The new debugfs_file_get() and debugfs_file_put(), intended to be used in place of former debugfs_use_file_start() and debugfs_use_file_finish(), increment and decrement it respectively. Once the count drops to zero, debugfs_file_put() will signal a completion which is possibly being waited for from debugfs_remove(). Thus, as long as there is a debugfs_file_get() not yet matched by a corresponding debugfs_file_put() around, debugfs_remove() will block. Actual users of debugfs_use_file_start() and -finish() will get converted to the new debugfs_file_get() and debugfs_file_put() by followup patches. Fixes: 49d200deaa68 ("debugfs: prevent access to removed files' private data") Reported-by: Johannes Berg Signed-off-by: Nicolai Stange Signed-off-by: Greg Kroah-Hartman

debugfs: add support for more elaborate ->d_fsdata

2017-11-07T19:25:02Z

Currently, the user provided fops, "real_fops", are stored directly into ->d_fsdata. In order to be able to store more per-file state and thus prepare for more granular file removal protection, wrap the real_fops into a dynamically allocated container struct, debugfs_fsdata. A struct debugfs_fsdata gets allocated at file creation and freed from the newly intoduced ->d_release(). Finally, move the implementation of debugfs_real_fops() out of the public debugfs header such that struct debugfs_fsdata's declaration can be kept private. Signed-off-by: Nicolai Stange Signed-off-by: Greg Kroah-Hartman