From 83762cb5c7c464af4cbaba5679af31c7fe534979 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Mon, 15 Nov 2021 13:20:57 -0800 Subject: dax: Kill DEV_DAX_PMEM_COMPAT The /sys/class/dax compatibility option has shipped in the kernel for 4 years now which should be sufficient time for tools to abandon the old ABI in favor of the /sys/bus/dax device-model. Delete it now and see if anyone screams. Since this compatibility option shipped there has been more reports of users being surprised by the compat ABI than surprised by the "new", so the compat infrastructure has outlived its usefulness. Recall that /sys/bus/dax device-model is required for the dax kmem driver which allows PMEM to be used as "System RAM". The following projects were known to have a dependency on /sys/class/dax and have dropped their dependency as of the listed version: - ndctl (including libndctl, daxctl, and libdaxctl): v64+ - fio: v3.13+ - pmdk: v1.5.2+ As further evidence this option is no longer needed some distributions have already stopped enabling CONFIG_DEV_DAX_PMEM_COMPAT. Cc: Ira Weiny Cc: Dave Jiang Reported-by: Vishal Verma Acked-by: Dave Hansen Reviewed-by: Jane Chu Link: https://lore.kernel.org/r/163701116195.3784476.726128179293466337.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams --- Documentation/ABI/obsolete/sysfs-class-dax | 22 ---------------------- 1 file changed, 22 deletions(-) delete mode 100644 Documentation/ABI/obsolete/sysfs-class-dax (limited to 'Documentation/ABI/obsolete') diff --git a/Documentation/ABI/obsolete/sysfs-class-dax b/Documentation/ABI/obsolete/sysfs-class-dax deleted file mode 100644 index 5bcce27458e3..000000000000 --- a/Documentation/ABI/obsolete/sysfs-class-dax +++ /dev/null @@ -1,22 +0,0 @@ -What: /sys/class/dax/ -Date: May, 2016 -KernelVersion: v4.7 -Contact: nvdimm@lists.linux.dev -Description: Device DAX is the device-centric analogue of Filesystem - DAX (CONFIG_FS_DAX). It allows memory ranges to be - allocated and mapped without need of an intervening file - system. Device DAX is strict, precise and predictable. - Specifically this interface: - - 1. Guarantees fault granularity with respect to a given - page size (pte, pmd, or pud) set at configuration time. - - 2. Enforces deterministic behavior by being strict about - what fault scenarios are supported. - - The /sys/class/dax/ interface enumerates all the - device-dax instances in the system. The ABI is - deprecated and will be removed after 2020. It is - replaced with the DAX bus interface /sys/bus/dax/ where - device-dax instances can be found under - /sys/bus/dax/devices/ -- cgit v1.2.3