1. Convert from get_user_pages(FOLL_LONGTERM) to pin_longterm_pages().
2. As required by pin_user_pages(), release these pages via put_user_page(). In this case, do so via put_user_pages_dirty_lock().
That has the side effect of calling set_page_dirty_lock(), instead of set_page_dirty(). This is probably more accurate.
As Christoph Hellwig put it, "set_page_dirty() is only safe if we are dealing with a file backed page where we have reference on the inode it hangs off." [1]
3. Release each page in mem->hpages[] (instead of mem->hpas[]), because that is the array that pin_longterm_pages() filled in. This is more accurate and should be a little safer from a maintenance point of view.
[1] https://lore.kernel.org/r/20190723153640.GB720@lst.de
Signed-off-by: John Hubbard jhubbard@nvidia.com --- arch/powerpc/mm/book3s64/iommu_api.c | 15 ++++++--------- 1 file changed, 6 insertions(+), 9 deletions(-)
diff --git a/arch/powerpc/mm/book3s64/iommu_api.c b/arch/powerpc/mm/book3s64/iommu_api.c index 56cc84520577..69d79cb50d47 100644 --- a/arch/powerpc/mm/book3s64/iommu_api.c +++ b/arch/powerpc/mm/book3s64/iommu_api.c @@ -103,9 +103,8 @@ static long mm_iommu_do_alloc(struct mm_struct *mm, unsigned long ua, for (entry = 0; entry < entries; entry += chunk) { unsigned long n = min(entries - entry, chunk);
- ret = get_user_pages(ua + (entry << PAGE_SHIFT), n, - FOLL_WRITE | FOLL_LONGTERM, - mem->hpages + entry, NULL); + ret = pin_longterm_pages(ua + (entry << PAGE_SHIFT), n, + FOLL_WRITE, mem->hpages + entry, NULL); if (ret == n) { pinned += n; continue; @@ -167,9 +166,8 @@ static long mm_iommu_do_alloc(struct mm_struct *mm, unsigned long ua, return 0;
free_exit: - /* free the reference taken */ - for (i = 0; i < pinned; i++) - put_page(mem->hpages[i]); + /* free the references taken */ + put_user_pages(mem->hpages, pinned);
vfree(mem->hpas); kfree(mem); @@ -212,10 +210,9 @@ static void mm_iommu_unpin(struct mm_iommu_table_group_mem_t *mem) if (!page) continue;
- if (mem->hpas[i] & MM_IOMMU_TABLE_GROUP_PAGE_DIRTY) - SetPageDirty(page); + put_user_pages_dirty_lock(&mem->hpages[i], 1, + MM_IOMMU_TABLE_GROUP_PAGE_DIRTY);
- put_page(page); mem->hpas[i] = 0; } }