The patch titled
Subject: mm/hmm: use a structure for update callback parameters
has been added to the -mm tree. Its filename is
mm-hmm-use-a-structure-for-update-callback-parameters-v2.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-hmm-use-a-structure-for-update-callback-parameters-v2.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-hmm-use-a-structure-for-update-callback-parameters-v2.patch
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------------------------------------------------------
From: Jérôme Glisse <jglisse@xxxxxxxxxx>
Subject: mm/hmm: use a structure for update callback parameters
Use a structure to gather all the parameters for the update callback.
This make it easier when adding new parameters by avoiding having to
update all callback function signature.
The hmm_update structure is always associated with a mmu_notifier
callbacks so we are not planing on grouping multiple updates together.
Nor do we care about page size for the range as range will over fully
cover the page being invalidated (this is a mmu_notifier property).
Link: http://lkml.kernel.org/r/20181019160442.18723-6-jglisse@xxxxxxxxxx
Signed-off-by: Jérôme Glisse <jglisse@xxxxxxxxxx>
Cc: Ralph Campbell <rcampbell@xxxxxxxxxx>
Cc: John Hubbard <jhubbard@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/hmm.h | 31 ++++++++++++++++++++++---------
mm/hmm.c | 33 ++++++++++++++++++++++-----------
2 files changed, 44 insertions(+), 20 deletions(-)
--- a/include/linux/hmm.h~mm-hmm-use-a-structure-for-update-callback-parameters-v2
+++ a/include/linux/hmm.h
@@ -274,14 +274,29 @@ static inline uint64_t hmm_pfn_from_pfn(
struct hmm_mirror;
/*
- * enum hmm_update_type - type of update
+ * enum hmm_update_event - type of update
* @HMM_UPDATE_INVALIDATE: invalidate range (no indication as to why)
*/
-enum hmm_update_type {
+enum hmm_update_event {
HMM_UPDATE_INVALIDATE,
};
/*
+ * struct hmm_update - HMM update informations for callback
+ *
+ * @start: virtual start address of the range to update
+ * @end: virtual end address of the range to update
+ * @event: event triggering the update (what is happening)
+ * @blockable: can the callback block/sleep ?
+ */
+struct hmm_update {
+ unsigned long start;
+ unsigned long end;
+ enum hmm_update_event event;
+ bool blockable;
+};
+
+/*
* struct hmm_mirror_ops - HMM mirror device operations callback
*
* @update: callback to update range on a device
@@ -300,9 +315,9 @@ struct hmm_mirror_ops {
/* sync_cpu_device_pagetables() - synchronize page tables
*
* @mirror: pointer to struct hmm_mirror
- * @update_type: type of update that occurred to the CPU page table
- * @start: virtual start address of the range to update
- * @end: virtual end address of the range to update
+ * @update: update informations (see struct hmm_update)
+ * Returns: -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
@@ -313,10 +328,8 @@ struct hmm_mirror_ops {
* page tables are completely updated (TLBs flushed, etc); this is a
* synchronous call.
*/
- void (*sync_cpu_device_pagetables)(struct hmm_mirror *mirror,
- enum hmm_update_type update_type,
- unsigned long start,
- unsigned long end);
+ int (*sync_cpu_device_pagetables)(struct hmm_mirror *mirror,
+ const struct hmm_update *update);
};
/*
--- a/mm/hmm.c~mm-hmm-use-a-structure-for-update-callback-parameters-v2
+++ a/mm/hmm.c
@@ -126,10 +126,8 @@ void hmm_mm_destroy(struct mm_struct *mm
kfree(mm->hmm);
}
-static void hmm_invalidate_range(struct hmm *hmm,
- enum hmm_update_type action,
- unsigned long start,
- unsigned long end)
+static int hmm_invalidate_range(struct hmm *hmm,
+ const struct hmm_update *update)
{
struct hmm_mirror *mirror;
struct hmm_range *range;
@@ -138,22 +136,30 @@ static void hmm_invalidate_range(struct
list_for_each_entry(range, &hmm->ranges, list) {
unsigned long addr, idx, npages;
- if (end < range->start || start >= range->end)
+ if (update->end < range->start || update->start >= range->end)
continue;
range->valid = false;
- addr = max(start, range->start);
+ addr = max(update->start, range->start);
idx = (addr - range->start) >> PAGE_SHIFT;
- npages = (min(range->end, end) - addr) >> PAGE_SHIFT;
+ npages = (min(range->end, update->end) - addr) >> PAGE_SHIFT;
memset(&range->pfns[idx], 0, sizeof(*range->pfns) * npages);
}
spin_unlock(&hmm->lock);
down_read(&hmm->mirrors_sem);
- list_for_each_entry(mirror, &hmm->mirrors, list)
- mirror->ops->sync_cpu_device_pagetables(mirror, action,
- start, end);
+ list_for_each_entry(mirror, &hmm->mirrors, list) {
+ int ret;
+
+ ret = mirror->ops->sync_cpu_device_pagetables(mirror, update);
+ if (!update->blockable && ret == -EAGAIN) {
+ up_read(&hmm->mirrors_sem);
+ return -EAGAIN;
+ }
+ }
up_read(&hmm->mirrors_sem);
+
+ return 0;
}
static void hmm_release(struct mmu_notifier *mn, struct mm_struct *mm)
@@ -202,11 +208,16 @@ static void hmm_invalidate_range_end(str
unsigned long start,
unsigned long end)
{
+ struct hmm_update update;
struct hmm *hmm = mm->hmm;
VM_BUG_ON(!hmm);
- hmm_invalidate_range(mm->hmm, HMM_UPDATE_INVALIDATE, start, end);
+ update.start = start;
+ update.end = end;
+ update.event = HMM_UPDATE_INVALIDATE;
+ update.blockable = true;
+ hmm_invalidate_range(hmm, &update);
}
static const struct mmu_notifier_ops hmm_mmu_notifier_ops = {
_
Patches currently in -mm which might be from jglisse@xxxxxxxxxx are
mm-hmm-fix-utf8.patch
mm-hmm-properly-handle-migration-pmd-v3.patch
mm-hmm-use-a-structure-for-update-callback-parameters-v2.patch
mm-hmm-invalidate-device-page-table-at-start-of-invalidation.patch
