There have been issues with get_user_pages and filesystem writeback. The issues are better described in [1]. The solution being proposed wants to keep track of gup_pinned pages which will allow to take furthur steps to coordinate between subsystems using gup. put_user_page() simply calls put_page inside for now. But the implementation will change once all call sites of put_page() are converted. I currently do not have the driver to test. Could I have some suggestions to test this code? The solution is currently implemented in [2] and it would be great if we could apply the patch on top of [2] and run some tests to check if any regressions occur. [1] https://lwn.net/Articles/753027/ [2] https://github.com/johnhubbard/linux/tree/gup_dma_core Cc: Matt Sickler <Matt.Sickler@xxxxxxxxxxxxxx> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Cc: Jérôme Glisse <jglisse@xxxxxxxxxx> Cc: Ira Weiny <ira.weiny@xxxxxxxxx> Cc: John Hubbard <jhubbard@xxxxxxxxxx> Cc: linux-mm@xxxxxxxxx Cc: devel@xxxxxxxxxxxxxxxxxxxx Signed-off-by: Bharath Vedartham <linux.bhar@xxxxxxxxx> --- drivers/staging/kpc2000/kpc_dma/fileops.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) diff --git a/drivers/staging/kpc2000/kpc_dma/fileops.c b/drivers/staging/kpc2000/kpc_dma/fileops.c index 6166587..82c70e6 100644 --- a/drivers/staging/kpc2000/kpc_dma/fileops.c +++ b/drivers/staging/kpc2000/kpc_dma/fileops.c @@ -198,9 +198,7 @@ int kpc_dma_transfer(struct dev_private_data *priv, struct kiocb *kcb, unsigned sg_free_table(&acd->sgt); err_dma_map_sg: err_alloc_sg_table: - for (i = 0 ; i < acd->page_count ; i++){ - put_page(acd->user_pages[i]); - } + put_user_pages(acd->user_pages, acd->page_count); err_get_user_pages: kfree(acd->user_pages); err_alloc_userpages: @@ -229,9 +227,7 @@ void transfer_complete_cb(struct aio_cb_data *acd, size_t xfr_count, u32 flags) dma_unmap_sg(&acd->ldev->pldev->dev, acd->sgt.sgl, acd->sgt.nents, acd->ldev->dir); - for (i = 0 ; i < acd->page_count ; i++){ - put_page(acd->user_pages[i]); - } + put_user_pages(acd->user_pages, acd->page_count); sg_free_table(&acd->sgt); -- 1.8.3.1 _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
