Messages in this thread Patch in this message | | | From | John Hubbard <> | Subject | [PATCH v3] fpga: dfl: afu: convert get_user_pages() --> pin_user_pages() | Date | Mon, 25 May 2020 15:17:54 -0700 |
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This code was using get_user_pages_fast(), in a "Case 2" scenario (DMA/RDMA), using the categorization from [1]. That means that it's time to convert the get_user_pages_fast() + put_page() calls to pin_user_pages_fast() + unpin_user_pages() calls.
There is some helpful background in [2]: basically, this is a small part of fixing a long-standing disconnect between pinning pages, and file systems' use of those pages.
[1] Documentation/core-api/pin_user_pages.rst
[2] "Explicit pinning of user-space pages": https://lwn.net/Articles/807108/
Cc: Xu Yilun <yilun.xu@intel.com> Cc: Wu Hao <hao.wu@intel.com> Cc: Moritz Fischer <mdf@kernel.org> Cc: linux-fpga@vger.kernel.org Signed-off-by: John Hubbard <jhubbard@nvidia.com> ---
Hi,
This is the same logical change as in v2, but it is applied to char-misc-next, in order to avoid a merge problem with Souptick's commit c9d7e3da1f3c ("fpga: dfl: afu: Corrected error handling levels <Souptick Joarder>")
thanks, John Hubbard NVIDIA
drivers/fpga/dfl-afu-dma-region.c | 19 +++++-------------- 1 file changed, 5 insertions(+), 14 deletions(-)
diff --git a/drivers/fpga/dfl-afu-dma-region.c b/drivers/fpga/dfl-afu-dma-region.c index 5942343a5d6e..0b817b722920 100644 --- a/drivers/fpga/dfl-afu-dma-region.c +++ b/drivers/fpga/dfl-afu-dma-region.c @@ -16,15 +16,6 @@ #include "dfl-afu.h" -static void put_all_pages(struct page **pages, int npages) -{ - int i; - - for (i = 0; i < npages; i++) - if (pages[i]) - put_page(pages[i]); -} - void afu_dma_region_init(struct dfl_feature_platform_data *pdata) { struct dfl_afu *afu = dfl_fpga_pdata_get_private(pdata); @@ -57,22 +48,22 @@ static int afu_dma_pin_pages(struct dfl_feature_platform_data *pdata, goto unlock_vm; } - pinned = get_user_pages_fast(region->user_addr, npages, FOLL_WRITE, + pinned = pin_user_pages_fast(region->user_addr, npages, FOLL_WRITE, region->pages); if (pinned < 0) { ret = pinned; goto free_pages; } else if (pinned != npages) { ret = -EFAULT; - goto put_pages; + goto unpin_pages; } dev_dbg(dev, "%d pages pinned\n", pinned); return 0; -put_pages: - put_all_pages(region->pages, pinned); +unpin_pages: + unpin_user_pages(region->pages, pinned); free_pages: kfree(region->pages); unlock_vm: @@ -94,7 +85,7 @@ static void afu_dma_unpin_pages(struct dfl_feature_platform_data *pdata, long npages = region->length >> PAGE_SHIFT; struct device *dev = &pdata->dev->dev; - put_all_pages(region->pages, npages); + unpin_user_pages(region->pages, npages); kfree(region->pages); account_locked_vm(current->mm, npages, false); -- 2.26.2
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