Device driver must properly toggle the dirty inside the mirror page table so dirtyness is properly accounted when core mm code needs to know. Provide a simple helper to toggle that bit for a range of address. Changed since v1: - Adapt to HMM page table changes. Signed-off-by: Jérôme Glisse <jglisse@xxxxxxxxxx> --- include/linux/hmm.h | 3 +++ mm/hmm.c | 38 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 41 insertions(+) diff --git a/include/linux/hmm.h b/include/linux/hmm.h index 10e1558..4bc132a 100644 --- a/include/linux/hmm.h +++ b/include/linux/hmm.h @@ -268,6 +268,9 @@ int hmm_mirror_fault(struct hmm_mirror *mirror, struct hmm_event *event); void hmm_mirror_range_discard(struct hmm_mirror *mirror, unsigned long start, unsigned long end); +void hmm_mirror_range_dirty(struct hmm_mirror *mirror, + unsigned long start, + unsigned long end); #endif /* CONFIG_HMM */ diff --git a/mm/hmm.c b/mm/hmm.c index 9f88df8..36cc506 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -941,6 +941,44 @@ void hmm_mirror_range_discard(struct hmm_mirror *mirror, } EXPORT_SYMBOL(hmm_mirror_range_discard); +/* hmm_mirror_range_dirty() - toggle dirty bit for a range of address. + * + * @mirror: The mirror struct. + * @start: Start address of the range to discard (inclusive). + * @end: End address of the range to discard (exclusive). + * + * Call when device driver want to toggle the dirty bit for a range of address. + * Useful when the device driver just want to toggle the bit for whole range + * without walking the mirror page table itself. + * + * Note this function does not directly dirty the page behind an address, but + * this will happen once address is invalidated or discard by device driver or + * core mm code. + */ +void hmm_mirror_range_dirty(struct hmm_mirror *mirror, + unsigned long start, + unsigned long end) +{ + struct hmm_pt_iter iter; + unsigned long addr; + + hmm_pt_iter_init(&iter, &mirror->pt); + for (addr = start; addr != end;) { + unsigned long next = end; + dma_addr_t *hmm_pte; + + hmm_pte = hmm_pt_iter_walk(&iter, &addr, &next); + for (; hmm_pte && addr != next; hmm_pte++, addr += PAGE_SIZE) { + if (!hmm_pte_test_valid_pfn(hmm_pte) || + !hmm_pte_test_write(hmm_pte)) + continue; + hmm_pte_set_dirty(hmm_pte); + } + } + hmm_pt_iter_fini(&iter); +} +EXPORT_SYMBOL(hmm_mirror_range_dirty); + /* hmm_mirror_register() - register mirror against current process for a device. * * @mirror: The mirror struct being registered. -- 2.4.3 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx"> email@xxxxxxxxx </a>