Re: [PATCH v9 20/25] powerpc: book3s64: convert to pin_user_pages() and put_user_page()
From: Jan Kara <jack@suse.cz>
Date: 2019-12-11 10:42:51
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On Tue 10-12-19 18:53:13, John Hubbard wrote:
1. Convert from get_user_pages() to pin_user_pages(). 2. As required by pin_user_pages(), release these pages via put_user_page(). Cc: Jan Kara <jack@suse.cz> Signed-off-by: John Hubbard <jhubbard@nvidia.com>
The patch looks good to me. You can add: Reviewed-by: Jan Kara <jack@suse.cz> I'd just note that mm_iommu_do_alloc() has a pre-existing bug that the last jump to 'free_exit' (at line 157) happens already after converting page pointers to physical addresses so put_page() calls there will just crash. But that's completely unrelated to your change. I'll send a fix separately. Honza
quoted hunk ↗ jump to hunk
--- arch/powerpc/mm/book3s64/iommu_api.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)diff --git a/arch/powerpc/mm/book3s64/iommu_api.c b/arch/powerpc/mm/book3s64/iommu_api.c index 56cc84520577..a86547822034 100644 --- a/arch/powerpc/mm/book3s64/iommu_api.c +++ b/arch/powerpc/mm/book3s64/iommu_api.c@@ -103,7 +103,7 @@ 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, + ret = pin_user_pages(ua + (entry << PAGE_SHIFT), n, FOLL_WRITE | FOLL_LONGTERM, mem->hpages + entry, NULL); if (ret == n) {@@ -167,9 +167,8 @@ 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);@@ -215,7 +214,8 @@ static void mm_iommu_unpin(struct mm_iommu_table_group_mem_t *mem) if (mem->hpas[i] & MM_IOMMU_TABLE_GROUP_PAGE_DIRTY) SetPageDirty(page); - put_page(page); + put_user_page(page); + mem->hpas[i] = 0; } }-- 2.24.0
-- Jan Kara [off-list ref] SUSE Labs, CR