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

fs/pipe: pre-allocate pages outside pipe->mutex in anon_pipe_write

2026-05-28T12:33:24+00:00

anon_pipe_write() takes pipe->mutex (aka "mutex protecting the whole thing") and then, from the per-iteration anon_pipe_get_page() helper, used to call alloc_page(GFP_HIGHUSER | __GFP_ACCOUNT) once per page while still holding it. That allocation can sleep doing direct reclaim and/or runs memcg charging, which extends the critical section and stalls a concurrent reader on the very same mutex. Just pre-alloc the required pages before the lock in an array and just pop them inside the lock. This can improve the pipe throughput up to 48% and reduce the latency in 33%, easily seen when there is memory pressure and direct reclaim. Reviewed-by: Mateusz Guzik Reviewed-by: Jeff Layton Signed-off-by: Breno Leitao Link: https://patch.msgid.link/20260524-fix_pipe-v3-1-bb4a75d23a90@debian.org Signed-off-by: Christian Brauner (Amutable)

fs/pipe: write to ->poll_usage only once

2026-05-21T11:39:36+00:00

Both GNU and BSD makes share a "token pipe" between their instances, as a result a -j $BIGNUM invocation results in multicore perf problems in the poll handler. Avoiding the store will reduce it a little bit. However, the crux of the problem is the locked queuing up in poll_wait(). Signed-off-by: Mateusz Guzik Link: https://patch.msgid.link/20260516021852.256932-1-mjguzik@gmail.com Signed-off-by: Christian Brauner (Amutable)

treewide: change inode->i_ino from unsigned long to u64

2026-03-06T13:31:28+00:00

On 32-bit architectures, unsigned long is only 32 bits wide, which causes 64-bit inode numbers to be silently truncated. Several filesystems (NFS, XFS, BTRFS, etc.) can generate inode numbers that exceed 32 bits, and this truncation can lead to inode number collisions and other subtle bugs on 32-bit systems. Change the type of inode->i_ino from unsigned long to u64 to ensure that inode numbers are always represented as 64-bit values regardless of architecture. Update all format specifiers treewide from %lu/%lx to %llu/%llx to match the new type, along with corresponding local variable types. This is the bulk treewide conversion. Earlier patches in this series handled trace events separately to allow trace field reordering for better struct packing on 32-bit. Signed-off-by: Jeff Layton Link: https://patch.msgid.link/20260304-iino-u64-v3-12-2257ad83d372@kernel.org Acked-by: Damien Le Moal Reviewed-by: Christoph Hellwig Reviewed-by: Jan Kara Reviewed-by: Chuck Lever 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

sysctl: Replace UINT converter macros with functions

2026-01-05T13:10:32+00:00

Replace the SYSCTL_USER_TO_KERN_UINT_CONV and SYSCTL_UINT_CONV_CUSTOM macros with functions with the same logic. This makes debugging easier and aligns with the functions preference described in coding-style.rst. Update the only user of this API: pipe.c. Signed-off-by: Joel Granados

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

2025-12-05T19:15:37+00:00

Pull sysctl updates from Joel Granados: - Move jiffies converters out of kernel/sysctl.c Move the jiffies converters into kernel/time/jiffies.c and replace the pipe-max-size proc_handler converter with a macro based version. This is all part of the effort to relocate non-sysctl logic out of kernel/sysctl.c into more relevant subsystems. No functional changes. - Generalize proc handler converter creation Remove duplicated sysctl converter logic by consolidating it in macros. These are used inside sysctl core as well as in pipe.c and jiffies.c. Converter kernel and user space pointer args are now automatically const qualified for the convenience of the caller. No functional changes. - Miscellaneous Fix kernel-doc format warnings, remove unnecessary __user qualifiers, and move the nmi_watchdog sysctl into .rodata. - Testing This series was run through sysctl selftests/kunit test suite in x86_64. It went into linux-next after rc2, giving it a good 4/5 weeks of testing. * tag 'sysctl-6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl: (21 commits) sysctl: Wrap do_proc_douintvec with the public function proc_douintvec_conv sysctl: Create pipe-max-size converter using sysctl UINT macros sysctl: Move proc_doulongvec_ms_jiffies_minmax to kernel/time/jiffies.c sysctl: Move jiffies converters to kernel/time/jiffies.c sysctl: Move UINT converter macros to sysctl header sysctl: Move INT converter macros to sysctl header sysctl: Allow custom converters from outside sysctl sysctl: remove __user qualifier from stack_erasing_sysctl buffer argument sysctl: Create macro for user-to-kernel uint converter sysctl: Add optional range checking to SYSCTL_UINT_CONV_CUSTOM sysctl: Create unsigned int converter using new macro sysctl: Add optional range checking to SYSCTL_INT_CONV_CUSTOM sysctl: Create integer converters with one macro sysctl: Create converter functions with two new macros sysctl: Discriminate between kernel and user converter params sysctl: Indicate the direction of operation with macro names sysctl: Remove superfluous __do_proc_* indirection sysctl: Remove superfluous tbl_data param from "dovec" functions sysctl: Replace void pointer with const pointer to ctl_table sysctl: fix kernel-doc format warning ...

sysctl: Wrap do_proc_douintvec with the public function proc_douintvec_conv

2025-11-27T14:45:38+00:00

Make do_proc_douintvec static and export proc_douintvec_conv wrapper function for external use. This is to keep with the design in sysctl.c. Update fs/pipe.c to use the new public API. Signed-off-by: Joel Granados

sysctl: Create pipe-max-size converter using sysctl UINT macros

2025-11-27T14:45:37+00:00

Create a converter for the pipe-max-size proc_handler using the SYSCTL_UINT_CONV_CUSTOM. Move SYSCTL_CONV_IDENTITY macro to the sysctl header to make it available for pipe size validation. Keep returning -EINVAL when (val == 0) by using a range checking converter and setting the minimal valid value (extern1) to SYSCTL_ONE. Keep round_pipe_size by passing it as the operation for SYSCTL_USER_TO_KERN_INT_CONV. Signed-off-by: Joel Granados

sysctl: Replace void pointer with const pointer to ctl_table

2025-11-27T14:43:20+00:00

* Replace void* data in the converter functions with a const struct ctl_table* table as it was only getting forwarding values from ctl_table->extra{1,2}. * Remove the void* data in the do_proc_* functions as they already had a pointer to the ctl_table. * Remove min/max structures do_proc_do{uint,int}vec_minmax_conv_param; the min/max values get passed directly in ctl_table. * Keep min/max initialization in extra{1,2} in proc_dou8vec_minmax. * The do_proc_douintvec was adjusted outside sysctl.c as it is exported to fs/pipe.c. Signed-off-by: Joel Granados

Coccinelle-based conversion to use ->i_state accessors

2025-10-20T18:22:26+00:00

All places were patched by coccinelle with the default expecting that ->i_lock is held, afterwards entries got fixed up by hand to use unlocked variants as needed. The script: @@ expression inode, flags; @@ - inode->i_state & flags + inode_state_read(inode) & flags @@ expression inode, flags; @@ - inode->i_state &= ~flags + inode_state_clear(inode, flags) @@ expression inode, flag1, flag2; @@ - inode->i_state &= ~flag1 & ~flag2 + inode_state_clear(inode, flag1 | flag2) @@ expression inode, flags; @@ - inode->i_state |= flags + inode_state_set(inode, flags) @@ expression inode, flags; @@ - inode->i_state = flags + inode_state_assign(inode, flags) @@ expression inode, flags; @@ - flags = inode->i_state + flags = inode_state_read(inode) @@ expression inode, flags; @@ - READ_ONCE(inode->i_state) & flags + inode_state_read(inode) & flags Signed-off-by: Mateusz Guzik Signed-off-by: Christian Brauner