Messages in this thread Patch in this message | | | From | John Hubbard <> | Subject | [PATCH 3/3] misc: xilinx-sdfec: convert get_user_pages() --> pin_user_pages() | Date | Tue, 26 May 2020 18:26:28 -0700 |
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This code was using get_user_pages*(), in approximately a "Case 1" scenario (Direct IO), using the categorization from [1]. That means that it's time to convert the get_user_pages*() + put_page() calls to pin_user_pages*() + 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: Derek Kiernan <derek.kiernan@xilinx.com> Cc: Dragan Cvetic <dragan.cvetic@xilinx.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Michal Simek <michal.simek@xilinx.com> Cc: linux-arm-kernel@lists.infradead.org Signed-off-by: John Hubbard <jhubbard@nvidia.com> --- drivers/misc/xilinx_sdfec.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-)
diff --git a/drivers/misc/xilinx_sdfec.c b/drivers/misc/xilinx_sdfec.c index 7e2ee3e547f2..cda3559025d5 100644 --- a/drivers/misc/xilinx_sdfec.c +++ b/drivers/misc/xilinx_sdfec.c @@ -627,12 +627,11 @@ static int xsdfec_table_write(struct xsdfec_dev *xsdfec, u32 offset, nr_pages = n; - res = get_user_pages_fast((unsigned long)src_ptr, nr_pages, 0, pages); + res = pin_user_pages_fast((unsigned long)src_ptr, nr_pages, 0, pages); if (res < nr_pages) { - if (res > 0) { - for (i = 0; i < res; i++) - put_page(pages[i]); - } + if (res > 0) + unpin_user_pages(pages, res); + return -EINVAL; } @@ -646,7 +645,7 @@ static int xsdfec_table_write(struct xsdfec_dev *xsdfec, u32 offset, reg++; } while ((reg < len) && ((reg * XSDFEC_REG_WIDTH_JUMP) % PAGE_SIZE)); - put_page(pages[i]); + unpin_user_page(pages[i]); } return 0; } -- 2.26.2
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