From: Jason Gunthorpe
The only two users of this are now converted to use mmu_interval_notifier,
delete all the code and update hmm.rst.
Reviewed-by: Jérôme Glisse
Tested-by: Ralph Campbell
Signed-off-by: Jason Gunthorpe
---
Documentation/vm/hmm.rst | 105 ---
include/linux/hmm.h | 183 +
mm/Kconfig | 1 -
mm/hmm.c | 285 ++-
4 files changed, 34 insertions(+), 540 deletions(-)
diff --git a/Documentation/vm/hmm.rst b/Documentation/vm/hmm.rst
index 0a5960beccf76d..893a8ba0e9fefb 100644
--- a/Documentation/vm/hmm.rst
+++ b/Documentation/vm/hmm.rst
@@ -147,49 +147,16 @@ Address space mirroring implementation and API
Address space mirroring's main objective is to allow duplication of a range of
CPU page table into a device page table; HMM helps keep both synchronized. A
device driver that wants to mirror a process address space must start with the
-registration of an hmm_mirror struct::
-
- int hmm_mirror_register(struct hmm_mirror *mirror,
- struct mm_struct *mm);
-
-The mirror struct has a set of callbacks that are used
-to propagate CPU page tables::
-
- struct hmm_mirror_ops {
- /* release() - release hmm_mirror
- *
- * @mirror: pointer to struct hmm_mirror
- *
- * This is called when the mm_struct is being released. The callback
- * must ensure that all access to any pages obtained from this mirror
- * is halted before the callback returns. All future access should
- * fault.
- */
- void (*release)(struct hmm_mirror *mirror);
-
- /* sync_cpu_device_pagetables() - synchronize page tables
- *
- * @mirror: pointer to struct hmm_mirror
- * @update: update information (see struct mmu_notifier_range)
- * Return: -EAGAIN if update.blockable false and callback need to
- * block, 0 otherwise.
- *
- * This callback ultimately originates from mmu_notifiers when the CPU
- * page table is updated. The device driver must update its page table
- * in response to this callback. The update argument tells what action
- * to perform.
- *
- * The device driver must not return from this callback until the device
- * page tables are completely updated (TLBs flushed, etc); this is a
- * synchronous call.
- */
- int (*sync_cpu_device_pagetables)(struct hmm_mirror *mirror,
- const struct hmm_update *update);
- };
-
-The device driver must perform the update action to the range (mark range
-read only, or fully unmap, etc.). The device must complete the update before
-the driver callback returns.
+registration of a mmu_interval_notifier::
+
+ mni->ops = &driver_ops;
+ int mmu_interval_notifier_insert(struct mmu_interval_notifier *mni,
+ unsigned long start, unsigned long length,
+ struct mm_struct *mm);
+
+During the driver_ops->invalidate() callback the device driver must perform
+the update action to the range (mark range read only, or fully unmap,
+etc.). The device must complete the update before the driver callback returns.
When the device driver wants to populate a range of virtual addresses, it can
use::
@@ -216,70 +183,46 @@ The usage pattern is::
struct hmm_range range;
...
+ range.notifier = &mni;
range.start = ...;
range.end = ...;
range.pfns = ...;
range.flags = ...;
range.values = ...;
range.pfn_shift = ...;
- hmm_range_register(&range, mirror);
- /*
- * Just wait for range to be valid, safe to ignore return value as we
- * will use the return value of hmm_range_fault() below under the
- * mmap_sem to ascertain the validity of the range.
- */
- hmm_range_wait_until_valid(&range, TIMEOUT_IN_MSEC);
+ if (!mmget_not_zero(mni->notifier.mm))
+ return -EFAULT;
again:
+ range.notifier_seq = mmu_interval_read_begin(&mni);
down_read(&mm->mmap_sem);
ret = hmm_range_fault(&range, HMM_RANGE_SNAPSHOT);
if (ret) {
up_read(&mm->mmap_sem);
- if (ret == -EBUSY) {
-/*
- * No need to check hmm_range_wait_until_valid() return value
- * on retry we will get proper error with hmm_range_fault()
- */
-hmm_range_wait_until_valid(&range, TIMEOUT_IN_MSEC);
-goto again;
- }
- hmm_range_unregister(&range);
+ if (ret == -EBUSY)
+ goto again;
return ret;
}
+ up_read(&mm->mmap_sem);
+
take_lock(driver->update);
- if (!hmm_range_valid(&range)) {
+ if (mmu_interval_read_retry(&ni, range.notifier_seq) {
release_lock(driver->update);
- up_read(&mm->mmap_sem);
goto again;
}
- // Use pfns array content to update d
