user/sven/linux.git/include/linux/debugfs.h, branch v6.13.1

debugfs: add small file operations for most files

2024-10-23T14:47:01Z

As struct file_operations is really big, but (most) debugfs files only use simple_open, read, write and perhaps seek, and don't need anything else, this wastes a lot of space for NULL pointers. Add a struct debugfs_short_fops and some bookkeeping code in debugfs so that users can use that with debugfs_create_file() using _Generic to figure out which function to use. Converting mac80211 to use it where possible saves quite a bit of space: 1010127 205064 1220 1216411 128f9b net/mac80211/mac80211.ko (before) 981199 205064 1220 1187483 121e9b net/mac80211/mac80211.ko (after) ------- -28928 = ~28KiB With a marginal space cost in debugfs: 8701 550 16 9267 2433 fs/debugfs/inode.o (before) 25233 325 32 25590 63f6 fs/debugfs/file.o (before) 8914 558 16 9488 2510 fs/debugfs/inode.o (after) 25380 325 32 25737 6489 fs/debugfs/file.o (after) --------------- +360 +8 (All on x86-64) A simple spatch suggests there are more than 300 instances, not even counting the ones hidden in macros like in mac80211, that could be trivially converted, for additional savings of about 240 bytes for each. Reviewed-by: Greg Kroah-Hartman Link: https://patch.msgid.link/20241022151838.26f9925fb959.Ia80b55e934bbfc45ce0df42a3233d34b35508046@changeid Signed-off-by: Johannes Berg

[tree-wide] finally take no_llseek out

2024-09-27T15:18:43Z

no_llseek had been defined to NULL two years ago, in commit 868941b14441 ("fs: remove no_llseek") To quote that commit, At -rc1 we'll need do a mechanical removal of no_llseek - git grep -l -w no_llseek | grep -v porting.rst | while read i; do sed -i '/\/d' $i done would do it. Unfortunately, that hadn't been done. Linus, could you do that now, so that we could finally put that thing to rest? All instances are of the form .llseek = no_llseek, so it's obviously safe. Signed-off-by: Al Viro Signed-off-by: Linus Torvalds

debugfs: add API to allow debugfs operations cancellation

2023-11-27T10:24:55Z

In some cases there might be longer-running hardware accesses in debugfs files, or attempts to acquire locks, and we want to still be able to quickly remove the files. Introduce a cancellations API to use inside the debugfs handler functions to be able to cancel such operations on a per-file basis. Acked-by: Greg Kroah-Hartman Signed-off-by: Johannes Berg

debugfs: fix error when writing negative value to atomic_t debugfs file

2022-12-01T00:13:16Z

The simple attribute files do not accept a negative value since the commit 488dac0c9237 ("libfs: fix error cast of negative value in simple_attr_write()"), so we have to use a 64-bit value to write a negative value for a debugfs file created by debugfs_create_atomic_t(). This restores the previous behaviour by introducing DEFINE_DEBUGFS_ATTRIBUTE_SIGNED for a signed value. Link: https://lkml.kernel.org/r/20220919172418.45257-4-akinobu.mita@gmail.com Fixes: 488dac0c9237 ("libfs: fix error cast of negative value in simple_attr_write()") Signed-off-by: Akinobu Mita Reported-by: Zhao Gongyi Reviewed-by: David Hildenbrand Reviewed-by: Greg Kroah-Hartman Cc: Alexander Viro Cc: Jonathan Corbet Cc: Oscar Salvador Cc: Rafael J. Wysocki Cc: Shuah Khan Cc: Wei Yongjun Cc: Yicong Yang Signed-off-by: Andrew Morton

debugfs: add debugfs_lookup_and_remove()

2022-09-05T11:02:34Z

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: remove return value of debugfs_create_ulong()

2021-05-21T18:59:55Z

No one checks the return value of debugfs_create_ulong(), as it's not needed, so make the return value void, so that no one tries to do so in the future. Link: https://lore.kernel.org/r/20210521184340.1348539-1-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman

debugfs: remove return value of debugfs_create_bool()

2021-05-21T18:59:03Z

No one checks the return value of debugfs_create_bool(), as it's not needed, so make the return value void, so that no one tries to do so in the future. Link: https://lore.kernel.org/r/20210521184519.1356639-1-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman

debugfs: Implement debugfs_create_str()

2021-04-16T15:06:34Z

Implement debugfs_create_str() to easily display names and such in debugfs. Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Greg Kroah-Hartman Tested-by: Valentin Schneider Link: https://lkml.kernel.org/r/20210412102001.415407080@infradead.org

debugfs: remove return value of debugfs_create_devm_seqfile()

2020-10-30T07:37:39Z

No one checks the return value of debugfs_create_devm_seqfile(), as it's not needed, so make the return value void, so that no one tries to do so in the future. Link: https://lore.kernel.org/r/20201023131037.2500765-1-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman

debugfs: make sure we can remove u32_array files cleanly

2020-07-10T20:54:00Z

debugfs_create_u32_array() allocates a small structure to wrap the data and size information about the array. If users ever try to remove the file this leads to a leak since nothing ever frees this wrapper. That said there are no upstream users of debugfs_create_u32_array() that'd remove a u32 array file (we only have one u32 array user in CMA), so there is no real bug here. Make callers pass a wrapper they allocated. This way the lifetime management of the wrapper is on the caller, and we can avoid the potential leak in debugfs. CC: Chucheng Luo Signed-off-by: Jakub Kicinski Reviewed-by: Greg Kroah-Hartman Signed-off-by: David S. Miller