kernel: move use_mm/unuse_mm to kthread.c

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>

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h
index 53b4126373a5a33df92bbf97cd12bf2a2fefe99d..b94bbb8e7bb4c96fd22c55f21a5466ba74bcf8fa 100644 (file)
--- 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>

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_arcturus.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_arcturus.c
index 6529caca88fe15ba65943413ede0f3b500c29d2f..35d4a5ab0228085936d4b92911377de42db5e3b7 100644 (file)
--- 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"

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v10.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v10.c
index 691c89705bcdc0aa1ab2fecbb0c8fad6acc28191..bf927f432506dc2cedac50fa387f15d6589d6b16 100644 (file)
--- 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"

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v7.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v7.c
index c6944739183a43981aed8b64e76de5c97f9f4dd1..744366c7ee85d33df316c9cc1586271846ea239d 100644 (file)
--- 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"

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v8.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v8.c
index 2f4bdc80a6b2dc0335972e0039de51f7af806924..feab4cc6e836765eb15d15a77715ddfd82b3d87e 100644 (file)
--- 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"

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v9.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v9.c
index df841c2ac5e741a5a4c8aa530f7b7d8c9c8ac8a2..c7fd0c47b254539028f12e0f0280d84165905db5 100644 (file)
--- 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"

diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index eee530453aa6772d94ea095dfe46bce3db8c7256..ad8a9df49f295f1dd7e94fc50303fa1e2e83e8c3 100644 (file)
--- 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>

diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
index 494f853f2206a1ca0bd54053152ad3bab3df622f..7ae54b7b637ba8236b02dbe2b8dcac2d74ec7327 100644 (file)
--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -32,7 +32,7 @@
 #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>
 

diff --git a/drivers/usb/gadget/legacy/inode.c b/drivers/usb/gadget/legacy/inode.c
index 3afddd3bea6e7197954fdaeedaf41034d9f59345..20fba95ed0a65faaa20acffc0f36e7fdaf00058c 100644 (file)
--- 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>

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 596132a96cd596e8117b87eb9701c4c8c686efb8..ffc7cc31d7eba006cabcb94bb2c8efc84254a676 100644 (file)
--- 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>

diff --git a/fs/aio.c b/fs/aio.c
index 7e079137fdcf5bd520d71751a420f7f79b10a51f..7ecddc2f38dbafe5f0e2f19ea70ff2a0bbf6387e 100644 (file)
--- 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>

diff --git a/fs/io-wq.c b/fs/io-wq.c
index 4023c9846860865a6461eaa3cc9ee27b620e5b8a..5f590bf27bffd97e2e95c93b9a5981132f46ddbf 100644 (file)
--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -10,7 +10,6 @@
 #include <linux/errno.h>
 #include <linux/sched/signal.h>
 #include <linux/mm.h>
-#include <linux/mmu_context.h>
 #include <linux/sched/mm.h>
 #include <linux/percpu.h>
 #include <linux/slab.h>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 9fb0dc6033ba32515b11da44e5803a5f4197e6cd..9842443dde203acaee8bec528dbfce78313e0e4a 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -55,7 +55,6 @@
 #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/kthread.h>

diff --git a/include/linux/kthread.h b/include/linux/kthread.h
index 8bbcaad7ef0f4ed684a5177fbf6062029b868616..c2d40c9672d67f1c7dd4424b58908ad3d90f385b 100644 (file)
--- 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,
@@ -198,6 +200,9 @@ bool kthread_cancel_delayed_work_sync(struct kthread_delayed_work *work);
 
 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

diff --git a/include/linux/mmu_context.h b/include/linux/mmu_context.h
index d9a543a9e1ccec60ea7ab8ce283e0f2bd9503566..c51a84132d7c08000f00e1edbabf6ceb2cfd8693 100644 (file)
--- 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

diff --git a/kernel/kthread.c b/kernel/kthread.c
index bfbfa481be3a56e3efb7641eb47fdd8f6a274c32..ce4610316377f5c6c07280e5b49f7b85f027dee3 100644 (file)
--- 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 kthread_worker *worker)
 }
 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

diff --git a/mm/Makefile b/mm/Makefile
index 662fd150464683454920a1d674a9bd3331f8e8b3..cc8f897dfac023b3fdb850821c4825d7ea1b5a66 100644 (file)
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -41,7 +41,7 @@ obj-y                 := filemap.o mempool.o oom_kill.o fadvise.o \
                           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)

diff --git a/mm/mmu_context.c b/mm/mmu_context.c
deleted file mode 100644 (file)
index 3e612ae..0000000
--- 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);