From: Christoph Hellwig <hch@lst.de>
Date: Wed, 10 Jun 2020 18:41:59 -0700
Subject: kernel: move use_mm/unuse_mm to kthread.c
Git-commit: 9bf5b9eb232b34738800868e30bea3bad4a6a1ba
Patch-mainline: v5.8-rc1
References: MM Functionality, bsc#1178426
[vbabka@suse.cz - SLE15-SP3 backport: we don't have fs/io-wq.c so leave out
that hunk ]
Patch series "improve use_mm / unuse_mm", v2.
This series improves the use_mm / unuse_mm interface by better documenting
the assumptions, and my taking the set_fs manipulations spread over the
callers into the core API.
This patch (of 3):
Use the proper API instead.
Link: http://lkml.kernel.org/r/20200404094101.672954-1-hch@lst.de
These helpers are only for use with kernel threads, and I will tie them
more into the kthread infrastructure going forward. Also move the
prototypes to kthread.h - mmu_context.h was a little weird to start with
as it otherwise contains very low-level MM bits.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Felipe Balbi <balbi@kernel.org>
Cc: Jason Wang <jasowang@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Cc: Zhi Wang <zhi.a.wang@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: http://lkml.kernel.org/r/20200404094101.672954-1-hch@lst.de
Link: http://lkml.kernel.org/r/20200416053158.586887-1-hch@lst.de
Link: http://lkml.kernel.org/r/20200404094101.672954-5-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h | 1
drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_arcturus.c | 1
drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v10.c | 1
drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v7.c | 2
drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v8.c | 2
drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v9.c | 2
drivers/gpu/drm/i915/gvt/kvmgt.c | 2
drivers/usb/gadget/function/f_fs.c | 2
drivers/usb/gadget/legacy/inode.c | 2
drivers/vhost/vhost.c | 1
fs/aio.c | 1
fs/io_uring.c | 1
include/linux/kthread.h | 5 +
include/linux/mmu_context.h | 5 -
kernel/kthread.c | 56 +++++++++++++++++
mm/Makefile | 2
mm/mmu_context.c | 64 --------------------
17 files changed, 66 insertions(+), 84 deletions(-)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
@@ -27,6 +27,7 @@
#include <linux/types.h>
#include <linux/mm.h>
+#include <linux/kthread.h>
#include <linux/workqueue.h>
#include <kgd_kfd_interface.h>
#include <drm/ttm/ttm_execbuf_util.h>
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_arcturus.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_arcturus.c
@@ -22,7 +22,6 @@
#include <linux/module.h>
#include <linux/fdtable.h>
#include <linux/uaccess.h>
-#include <linux/mmu_context.h>
#include <linux/firmware.h>
#include "amdgpu.h"
#include "amdgpu_amdkfd.h"
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v10.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v10.c
@@ -19,7 +19,6 @@
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
-#include <linux/mmu_context.h>
#include "amdgpu.h"
#include "amdgpu_amdkfd.h"
#include "gc/gc_10_1_0_offset.h"
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v7.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v7.c
@@ -20,8 +20,6 @@
* OTHER DEALINGS IN THE SOFTWARE.
*/
-#include <linux/mmu_context.h>
-
#include "amdgpu.h"
#include "amdgpu_amdkfd.h"
#include "cikd.h"
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v8.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v8.c
@@ -20,8 +20,6 @@
* OTHER DEALINGS IN THE SOFTWARE.
*/
-#include <linux/mmu_context.h>
-
#include "amdgpu.h"
#include "amdgpu_amdkfd.h"
#include "gfx_v8_0.h"
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v9.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v9.c
@@ -19,8 +19,6 @@
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
-#include <linux/mmu_context.h>
-
#include "amdgpu.h"
#include "amdgpu_amdkfd.h"
#include "gc/gc_9_0_offset.h"
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -31,7 +31,7 @@
#include <linux/init.h>
#include <linux/device.h>
#include <linux/mm.h>
-#include <linux/mmu_context.h>
+#include <linux/kthread.h>
#include <linux/sched/mm.h>
#include <linux/types.h>
#include <linux/list.h>
--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -31,7 +31,7 @@
#include <linux/usb/functionfs.h>
#include <linux/aio.h>
-#include <linux/mmu_context.h>
+#include <linux/kthread.h>
#include <linux/poll.h>
#include <linux/eventfd.h>
--- a/drivers/usb/gadget/legacy/inode.c
+++ b/drivers/usb/gadget/legacy/inode.c
@@ -21,7 +21,7 @@
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/poll.h>
-#include <linux/mmu_context.h>
+#include <linux/kthread.h>
#include <linux/aio.h>
#include <linux/uio.h>
#include <linux/refcount.h>
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -14,7 +14,6 @@
#include <linux/vhost.h>
#include <linux/uio.h>
#include <linux/mm.h>
-#include <linux/mmu_context.h>
#include <linux/miscdevice.h>
#include <linux/mutex.h>
#include <linux/poll.h>
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -27,7 +27,6 @@
#include <linux/file.h>
#include <linux/mm.h>
#include <linux/mman.h>
-#include <linux/mmu_context.h>
#include <linux/percpu.h>
#include <linux/slab.h>
#include <linux/timer.h>
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -53,7 +53,6 @@
#include <linux/fdtable.h>
#include <linux/mm.h>
#include <linux/mman.h>
-#include <linux/mmu_context.h>
#include <linux/percpu.h>
#include <linux/slab.h>
#include <linux/workqueue.h>
--- a/include/linux/kthread.h
+++ b/include/linux/kthread.h
@@ -5,6 +5,8 @@
#include <linux/err.h>
#include <linux/sched.h>
+struct mm_struct;
+
__printf(4, 5)
struct task_struct *kthread_create_on_node(int (*threadfn)(void *data),
void *data,
@@ -197,6 +199,9 @@ bool kthread_cancel_delayed_work_sync(st
void kthread_destroy_worker(struct kthread_worker *worker);
+void use_mm(struct mm_struct *mm);
+void unuse_mm(struct mm_struct *mm);
+
struct cgroup_subsys_state;
#ifdef CONFIG_BLK_CGROUP
--- a/include/linux/mmu_context.h
+++ b/include/linux/mmu_context.h
@@ -4,11 +4,6 @@
#include <asm/mmu_context.h>
-struct mm_struct;
-
-void use_mm(struct mm_struct *mm);
-void unuse_mm(struct mm_struct *mm);
-
/* Architectures that care about IRQ state in switch_mm can override this. */
#ifndef switch_mm_irqs_off
# define switch_mm_irqs_off switch_mm
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -1,13 +1,17 @@
// SPDX-License-Identifier: GPL-2.0-only
/* Kernel thread helper functions.
* Copyright (C) 2004 IBM Corporation, Rusty Russell.
+ * Copyright (C) 2009 Red Hat, Inc.
*
* Creation is done via kthreadd, so that we get a clean environment
* even if we're invoked from userspace (think modprobe, hotplug cpu,
* etc.).
*/
#include <uapi/linux/sched/types.h>
+#include <linux/mm.h>
+#include <linux/mmu_context.h>
#include <linux/sched.h>
+#include <linux/sched/mm.h>
#include <linux/sched/task.h>
#include <linux/kthread.h>
#include <linux/completion.h>
@@ -25,6 +29,7 @@
#include <linux/numa.h>
#include <trace/events/sched.h>
+
static DEFINE_SPINLOCK(kthread_create_lock);
static LIST_HEAD(kthread_create_list);
struct task_struct *kthreadd_task;
@@ -1203,6 +1208,57 @@ void kthread_destroy_worker(struct kthre
}
EXPORT_SYMBOL(kthread_destroy_worker);
+/*
+ * use_mm
+ * Makes the calling kernel thread take on the specified
+ * mm context.
+ * (Note: this routine is intended to be called only
+ * from a kernel thread context)
+ */
+void use_mm(struct mm_struct *mm)
+{
+ struct mm_struct *active_mm;
+ struct task_struct *tsk = current;
+
+ task_lock(tsk);
+ active_mm = tsk->active_mm;
+ if (active_mm != mm) {
+ mmgrab(mm);
+ tsk->active_mm = mm;
+ }
+ tsk->mm = mm;
+ switch_mm(active_mm, mm, tsk);
+ task_unlock(tsk);
+#ifdef finish_arch_post_lock_switch
+ finish_arch_post_lock_switch();
+#endif
+
+ if (active_mm != mm)
+ mmdrop(active_mm);
+}
+EXPORT_SYMBOL_GPL(use_mm);
+
+/*
+ * unuse_mm
+ * Reverses the effect of use_mm, i.e. releases the
+ * specified mm context which was earlier taken on
+ * by the calling kernel thread
+ * (Note: this routine is intended to be called only
+ * from a kernel thread context)
+ */
+void unuse_mm(struct mm_struct *mm)
+{
+ struct task_struct *tsk = current;
+
+ task_lock(tsk);
+ sync_mm_rss(mm);
+ tsk->mm = NULL;
+ /* active_mm is still 'mm' */
+ enter_lazy_tlb(mm, tsk);
+ task_unlock(tsk);
+}
+EXPORT_SYMBOL_GPL(unuse_mm);
+
#ifdef CONFIG_BLK_CGROUP
/**
* kthread_associate_blkcg - associate blkcg to current kthread
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -36,7 +36,7 @@ obj-y := filemap.o mempool.o oom_kill.
maccess.o page-writeback.o \
readahead.o swap.o truncate.o vmscan.o shmem.o \
util.o mmzone.o vmstat.o backing-dev.o \
- mm_init.o mmu_context.o percpu.o slab_common.o \
+ mm_init.o percpu.o slab_common.o \
compaction.o vmacache.o \
interval_tree.o list_lru.o workingset.o \
debug.o gup.o $(mmu-y)
--- a/mm/mmu_context.c
+++ /dev/null
@@ -1,64 +0,0 @@
-/* Copyright (C) 2009 Red Hat, Inc.
- *
- * See ../COPYING for licensing terms.
- */
-
-#include <linux/mm.h>
-#include <linux/sched.h>
-#include <linux/sched/mm.h>
-#include <linux/sched/task.h>
-#include <linux/mmu_context.h>
-#include <linux/export.h>
-
-#include <asm/mmu_context.h>
-
-/*
- * use_mm
- * Makes the calling kernel thread take on the specified
- * mm context.
- * (Note: this routine is intended to be called only
- * from a kernel thread context)
- */
-void use_mm(struct mm_struct *mm)
-{
- struct mm_struct *active_mm;
- struct task_struct *tsk = current;
-
- task_lock(tsk);
- active_mm = tsk->active_mm;
- if (active_mm != mm) {
- mmgrab(mm);
- tsk->active_mm = mm;
- }
- tsk->mm = mm;
- switch_mm(active_mm, mm, tsk);
- task_unlock(tsk);
-#ifdef finish_arch_post_lock_switch
- finish_arch_post_lock_switch();
-#endif
-
- if (active_mm != mm)
- mmdrop(active_mm);
-}
-EXPORT_SYMBOL_GPL(use_mm);
-
-/*
- * unuse_mm
- * Reverses the effect of use_mm, i.e. releases the
- * specified mm context which was earlier taken on
- * by the calling kernel thread
- * (Note: this routine is intended to be called only
- * from a kernel thread context)
- */
-void unuse_mm(struct mm_struct *mm)
-{
- struct task_struct *tsk = current;
-
- task_lock(tsk);
- sync_mm_rss(mm);
- tsk->mm = NULL;
- /* active_mm is still 'mm' */
- enter_lazy_tlb(mm, tsk);
- task_unlock(tsk);
-}
-EXPORT_SYMBOL_GPL(unuse_mm);