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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-24 08:46:03 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-24 08:46:03 -0700 |
| commit | cf9610f9116d55c5a66ef9f1faecacabd93a9322 (patch) | |
| tree | 757a3d280760c654767631cab5ad8af2d86d1848 /Documentation/filesystems/locks.rst | |
| download | linux-stable-cf9610f9116d55c5a66ef9f1faecacabd93a9322.tar.gz linux-stable-cf9610f9116d55c5a66ef9f1faecacabd93a9322.zip | |
Merge tag 'pinctrl-v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrlgrafted
Pull pin control updates from Linus Walleij:
"Core changes:
- Use the non-blocking mux_state_try_select() in the generic MUX pin
control back-end
- Free pin maps on pinctrl_generic_to_map() failure in the core
helpers
New hardware pin control:
- Qualcomm Maili TLMM SoC, PMG1110 PMIC, and Eliza LPASS LPI TLMM SoC
(this is for the low power audio, LPASS = Low Power Audio SubSystem
portions)
- Upboard support on top of the Intel pin controller
- Apple T6030 and T6031 support (just compatible strings)
- Samsung Exynos 8855 SoC
- Mediatek MT6858 SoC
- Rockchip RK3308B and RV1106 SoCs
- Airoha EN7523 and AN7563 SoCs
Improvements:
- Qualcomm TLMM GPIOs are unconditionally marked as wakeup capable
- Qualcomm improvements on top of the Qualcomm PDC (power domain
controller) irqchip improvements from tglx:s tree
- Qualcomm IPQ806x and IPQ9650 non-urgent pin grop fixups
- The NPCM8xx driver has been put into shape fixing many pin and
group definitions
- Some non-urgent Tegra 264 pin assignments are fixed up
- Some non-urgent fixups to Airoha AN7581 and AN7583 registers and
pin assignments, missing features etc"
* tag 'pinctrl-v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl: (130 commits)
dt-bindings: pinctrl: Convert TI DA850 pupd to DT schema
pinctrl: meson: sync some modify from A4
pinctrl: meson: a4: Add input enable pin configuration
pinctrl: realtek: rtd1625: remove unused group name spdif_sel
pinctrl: realtek: rtd1625: fix base_bit for VE4 GPIO 13
dt-bindings: pinctrl: microchip,pic32mzda-pinctrl: Convert to DT schema
Revert "Merge branch 'ib-rsk7204' into devel"
pinctrl: rockchip: Add RV1106 pinctrl support
dt-bindings: pinctrl: rockchip: Add RV1106 compatible
pinctrl: rockchip: Decode drive strength in the get function
pinctrl: fix PINCTRL_GENERIC_MUX not always being selectable
pinctrl: airoha: add support of an7563 SoC
dt-bindings: pinctrl: airoha: add support of an7563 pin controller
pinctrl: airoha: try to find chip scu node by phandle first
pinctrl: airoha: add support of en7523 SoC
dt-bindings: pinctrl: airoha: add support of en7523 pin controller
pinctrl: airoha: an7583: add support for olt pinmux
pinctrl: airoha: an7583: add support for pon_alt pinmux
pinctrl: airoha: an7583: add support for npu_uart pinmux
dt-bindings: pinctrl: airoha: an7583: add missed features
...
Diffstat (limited to 'Documentation/filesystems/locks.rst')
| -rw-r--r-- | Documentation/filesystems/locks.rst | 65 |
1 files changed, 65 insertions, 0 deletions
diff --git a/Documentation/filesystems/locks.rst b/Documentation/filesystems/locks.rst new file mode 100644 index 000000000..26429317d --- /dev/null +++ b/Documentation/filesystems/locks.rst @@ -0,0 +1,65 @@ +.. SPDX-License-Identifier: GPL-2.0 + +========================== +File Locking Release Notes +========================== + + Andy Walker <andy@lysaker.kvaerner.no> + + 12 May 1997 + + +1. What's New? +============== + +1.1 Broken Flock Emulation +-------------------------- + +The old flock(2) emulation in the kernel was swapped for proper BSD +compatible flock(2) support in the 1.3.x series of kernels. With the +release of the 2.1.x kernel series, support for the old emulation has +been totally removed, so that we don't need to carry this baggage +forever. + +This should not cause problems for anybody, since everybody using a +2.1.x kernel should have updated their C library to a suitable version +anyway (see the file "Documentation/process/changes.rst".) + +1.2 Allow Mixed Locks Again +--------------------------- + +1.2.1 Typical Problems - Sendmail +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ +Because sendmail was unable to use the old flock() emulation, many sendmail +installations use fcntl() instead of flock(). This is true of Slackware 3.0 +for example. This gave rise to some other subtle problems if sendmail was +configured to rebuild the alias file. Sendmail tried to lock the aliases.dir +file with fcntl() at the same time as the GDBM routines tried to lock this +file with flock(). With pre 1.3.96 kernels this could result in deadlocks that, +over time, or under a very heavy mail load, would eventually cause the kernel +to lock solid with deadlocked processes. + + +1.2.2 The Solution +^^^^^^^^^^^^^^^^^^ +The solution I have chosen, after much experimentation and discussion, +is to make flock() and fcntl() locks oblivious to each other. Both can +exists, and neither will have any effect on the other. + +I wanted the two lock styles to be cooperative, but there were so many +race and deadlock conditions that the current solution was the only +practical one. It puts us in the same position as, for example, SunOS +4.1.x and several other commercial Unices. The only OS's that support +cooperative flock()/fcntl() are those that emulate flock() using +fcntl(), with all the problems that implies. + + +1.3 Mandatory Locking As A Mount Option +--------------------------------------- + +Mandatory locking was prior to this release a general configuration option +that was valid for all mounted filesystems. This had a number of inherent +dangers, not the least of which was the ability to freeze an NFS server by +asking it to read a file for which a mandatory lock existed. + +Such option was dropped in Kernel v5.14. |
