kernel/linux.git/fs/file.c, branch v7.2-rc1

fs: retire stale comment in fget_task_next()

2026-05-28T12:27:00+00:00

The routine originally showed up in e9a53aeb5e0a838f ("file: Implement task_lookup_next_fd_rcu"), afterwards it got renamed and started entering RCU on its own in 8fd3395ec9051a52 ("get rid of ...lookup...fdget_rcu() family"). Signed-off-by: Mateusz Guzik Link: https://patch.msgid.link/20260522142152.1515572-1-mjguzik@gmail.com Reviewed-by: Jan Kara Signed-off-by: Christian Brauner (Amutable)

vfs: remove always taken if-branch in find_next_fd()

2026-05-21T07:32:47+00:00

find_next_fd() finds the next free fd slot in the passed fdtable's bitmap. It does so in two steps: first it checks whether the bitmap has a free entry in the word containing start. If not, it looks at second level bitmap that registers which words in the first level bitmap are full and then looks at the first level bitmap at the first non-full word. In the current code the second level lookup is done by: bitbit = find_next_zero_bit(fdt->full_fds_bits, maxbit, bitbit) * BITS_PER_LONG; where bitbit = start / BITS_PER_LONG. However, in the fast path (first step) we already checked the word at bitbit, so we can skip that word bit and start at bitbit+1. This also means that we can get rid of the branch if (bitbit > start) start = bitbit; since if we set bitbit = find_next_zero_bit(fdt->full_fds_bits, maxbit, bitbit+1) * BITS_PER_LONG; the reassigned bitbit can never be less than ((start/BITS_PER_LONG)+1) * BITS_PER_LONG > start So the branch is always taken. Obviously the reuse of the variable name bitbit (and the name itself) is quite confusing, so change that as well. Signed-off-by: Jori Koolstra Link: https://patch.msgid.link/20260420101801.806785-1-jkoolstra@xs4all.nl Reviewed-by: Jan Kara Signed-off-by: Christian Brauner

Merge tag 'vfs-7.1-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

2026-04-13T21:20:11+00:00

Pull misc vfs updates from Christian Brauner: "Features: - coredump: add tracepoint for coredump events - fs: hide file and bfile caches behind runtime const machinery Fixes: - fix architecture-specific compat_ftruncate64 implementations - dcache: Limit the minimal number of bucket to two - fs/omfs: reject s_sys_blocksize smaller than OMFS_DIR_START - fs/mbcache: cancel shrink work before destroying the cache - dcache: permit dynamic_dname()s up to NAME_MAX Cleanups: - remove or unexport unused fs_context infrastructure - trivial ->setattr cleanups - selftests/filesystems: Assume that TIOCGPTPEER is defined - writeback: fix kernel-doc function name mismatch for wb_put_many() - autofs: replace manual symlink buffer allocation in autofs_dir_symlink - init/initramfs.c: trivial fix: FSM -> Finite-state machine - fs: remove stale and duplicate forward declarations - readdir: Introduce dirent_size() - fs: Replace user_access_{begin/end} by scoped user access - kernel: acct: fix duplicate word in comment - fs: write a better comment in step_into() concerning .mnt assignment - fs: attr: fix comment formatting and spelling issues" * tag 'vfs-7.1-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (28 commits) dcache: permit dynamic_dname()s up to NAME_MAX fs: attr: fix comment formatting and spelling issues fs: hide file and bfile caches behind runtime const machinery fs: write a better comment in step_into() concerning .mnt assignment proc: rename proc_notify_change to proc_setattr proc: rename proc_setattr to proc_nochmod_setattr affs: rename affs_notify_change to affs_setattr adfs: rename adfs_notify_change to adfs_setattr hfs: update comments on hfs_inode_setattr kernel: acct: fix duplicate word in comment fs: Replace user_access_{begin/end} by scoped user access readdir: Introduce dirent_size() coredump: add tracepoint for coredump events fs: remove do_sys_truncate fs: pass on FTRUNCATE_* flags to do_truncate fs: fix archiecture-specific compat_ftruncate64 fs: remove stale and duplicate forward declarations init/initramfs.c: trivial fix: FSM -> Finite-state machine autofs: replace manual symlink buffer allocation in autofs_dir_symlink fs/mbcache: cancel shrink work before destroying the cache ...

fs: hide file and bfile caches behind runtime const machinery

2026-03-31T09:43:34+00:00

s/cachep/cache/ for consistency with namei and dentry caches. Signed-off-by: Mateusz Guzik Link: https://patch.msgid.link/20260328173728.3388070-1-mjguzik@gmail.com Reviewed-by: Jan Kara Signed-off-by: Christian Brauner

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28+00:00

This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook

fs/file: optimize close_range() complexity from O(N) to O(Sparse)

2026-01-23T10:31:49+00:00

In close_range(), the kernel traditionally performs a linear scan over the [fd, max_fd] range, resulting in O(N) complexity where N is the range size. For processes with sparse FD tables, this is inefficient as it checks many unallocated slots. This patch optimizes __range_close() by using find_next_bit() on the open_fds bitmap to skip holes. This shifts the algorithmic complexity from O(Range Size) to O(Active FDs), providing a significant performance boost for large-range close operations on sparse file descriptor tables. Signed-off-by: Qiliang Yuan Signed-off-by: Qiliang Yuan Link: https://patch.msgid.link/20260123081221.659125-1-realwujing@gmail.com Signed-off-by: Christian Brauner

Merge tag 'vfs-6.19-rc1.fd_prepare.fs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

2025-12-02T01:32:07+00:00

Pull fd prepare updates from Christian Brauner: "This adds the FD_ADD() and FD_PREPARE() primitive. They simplify the common pattern of get_unused_fd_flags() + create file + fd_install() that is used extensively throughout the kernel and currently requires cumbersome cleanup paths. FD_ADD() - For simple cases where a file is installed immediately: fd = FD_ADD(O_CLOEXEC, vfio_device_open_file(device)); if (fd < 0) vfio_device_put_registration(device); return fd; FD_PREPARE() - For cases requiring access to the fd or file, or additional work before publishing: FD_PREPARE(fdf, O_CLOEXEC, sync_file->file); if (fdf.err) { fput(sync_file->file); return fdf.err; } data.fence = fd_prepare_fd(fdf); if (copy_to_user((void __user *)arg, &data, sizeof(data))) return -EFAULT; return fd_publish(fdf); The primitives are centered around struct fd_prepare. FD_PREPARE() encapsulates all allocation and cleanup logic and must be followed by a call to fd_publish() which associates the fd with the file and installs it into the caller's fdtable. If fd_publish() isn't called, both are deallocated automatically. FD_ADD() is a shorthand that does fd_publish() immediately and never exposes the struct to the caller. I've implemented this in a way that it's compatible with the cleanup infrastructure while also being usable separately. IOW, it's centered around struct fd_prepare which is aliased to class_fd_prepare_t and so we can make use of all the basica guard infrastructure" * tag 'vfs-6.19-rc1.fd_prepare.fs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (42 commits) io_uring: convert io_create_mock_file() to FD_PREPARE() file: convert replace_fd() to FD_PREPARE() vfio: convert vfio_group_ioctl_get_device_fd() to FD_ADD() tty: convert ptm_open_peer() to FD_ADD() ntsync: convert ntsync_obj_get_fd() to FD_PREPARE() media: convert media_request_alloc() to FD_PREPARE() hv: convert mshv_ioctl_create_partition() to FD_ADD() gpio: convert linehandle_create() to FD_PREPARE() pseries: port papr_rtas_setup_file_interface() to FD_ADD() pseries: convert papr_platform_dump_create_handle() to FD_ADD() spufs: convert spufs_gang_open() to FD_PREPARE() papr-hvpipe: convert papr_hvpipe_dev_create_handle() to FD_PREPARE() spufs: convert spufs_context_open() to FD_PREPARE() net/socket: convert __sys_accept4_file() to FD_ADD() net/socket: convert sock_map_fd() to FD_ADD() net/kcm: convert kcm_ioctl() to FD_PREPARE() net/handshake: convert handshake_nl_accept_doit() to FD_PREPARE() secretmem: convert memfd_secret() to FD_ADD() memfd: convert memfd_create() to FD_ADD() bpf: convert bpf_token_create() to FD_PREPARE() ...

file: convert replace_fd() to FD_PREPARE()

2025-11-28T11:42:36+00:00

Link: https://patch.msgid.link/20251123-work-fd-prepare-v4-44-b6efa1706cfd@kernel.org Signed-off-by: Christian Brauner

fs: move fd_install() slowpath into a dedicated routine and provide commentary

2025-11-12T11:19:09+00:00

On stock kernel gcc 14 emits avoidable register spillage: endbr64 call ffffffff81374630 <__fentry__> push %r13 push %r12 push %rbx sub $0x8,%rsp [snip] Total fast path is 99 bytes. Moving the slowpath out avoids it and shortens the fast path to 74 bytes. Signed-off-by: Mateusz Guzik Link: https://patch.msgid.link/20251110095634.1433061-1-mjguzik@gmail.com Signed-off-by: Christian Brauner

fs: always return zero on success from replace_fd()

2025-08-11T12:52:25+00:00

replace_fd() returns the number of the new file descriptor through the return value of do_dup2(). However its callers never care about the specific returned number. In fact the caller in receive_fd_replace() treats any non-zero return value as an error and therefore never calls __receive_sock() for most file descriptors, which is a bug. To fix the bug in receive_fd_replace() and to avoid the same issue happening in future callers, signal success through a plain zero. Suggested-by: Al Viro Link: https://lore.kernel.org/lkml/20250801220215.GS222315@ZenIV/ Fixes: 173817151b15 ("fs: Expand __receive_fd() to accept existing fd") Fixes: 42eb0d54c08a ("fs: split receive_fd_replace from __receive_fd") Cc: stable@vger.kernel.org Signed-off-by: Thomas Weißschuh Link: https://lore.kernel.org/20250805-fix-receive_fd_replace-v3-1-b72ba8b34bac@linutronix.de Signed-off-by: Christian Brauner