Messages in this thread Patch in this message | | | From | John Hubbard <> | Subject | [PATCH] genwqe: convert get_user_pages() --> pin_user_pages() | Date | Sun, 17 May 2020 18:52:37 -0700 |
| |
This code was using get_user_pages*(), in a "Case 2" scenario (DMA/RDMA), 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: Frank Haverkamp <haver@linux.ibm.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: John Hubbard <jhubbard@nvidia.com> ---
Hi,
Note that I have only compile-tested this patch, although that does also include cross-compiling for a few other arches...but it only seemed to be supported on x86_64 and sparc, for those.
thanks, John Hubbard NVIDIA
drivers/misc/genwqe/card_utils.c | 42 +++++++------------------------- 1 file changed, 9 insertions(+), 33 deletions(-)
diff --git a/drivers/misc/genwqe/card_utils.c b/drivers/misc/genwqe/card_utils.c index 2e1c4d2905e8..60460a053b2d 100644 --- a/drivers/misc/genwqe/card_utils.c +++ b/drivers/misc/genwqe/card_utils.c @@ -514,30 +514,6 @@ int genwqe_free_sync_sgl(struct genwqe_dev *cd, struct genwqe_sgl *sgl) return rc; } -/** - * genwqe_free_user_pages() - Give pinned pages back - * - * Documentation of get_user_pages is in mm/gup.c: - * - * If the page is written to, set_page_dirty (or set_page_dirty_lock, - * as appropriate) must be called after the page is finished with, and - * before put_page is called. - */ -static int genwqe_free_user_pages(struct page **page_list, - unsigned int nr_pages, int dirty) -{ - unsigned int i; - - for (i = 0; i < nr_pages; i++) { - if (page_list[i] != NULL) { - if (dirty) - set_page_dirty_lock(page_list[i]); - put_page(page_list[i]); - } - } - return 0; -} - /** * genwqe_user_vmap() - Map user-space memory to virtual kernel memory * @cd: pointer to genwqe device @@ -597,18 +573,18 @@ int genwqe_user_vmap(struct genwqe_dev *cd, struct dma_mapping *m, void *uaddr, m->dma_list = (dma_addr_t *)(m->page_list + m->nr_pages); /* pin user pages in memory */ - rc = get_user_pages_fast(data & PAGE_MASK, /* page aligned addr */ + rc = pin_user_pages_fast(data & PAGE_MASK, /* page aligned addr */ m->nr_pages, m->write ? FOLL_WRITE : 0, /* readable/writable */ m->page_list); /* ptrs to pages */ if (rc < 0) - goto fail_get_user_pages; + goto fail_pin_user_pages; - /* assumption: get_user_pages can be killed by signals. */ + /* assumption: pin_user_pages can be killed by signals. */ if (rc < m->nr_pages) { - genwqe_free_user_pages(m->page_list, rc, m->write); + unpin_user_pages_dirty_lock(m->page_list, rc, m->write); rc = -EFAULT; - goto fail_get_user_pages; + goto fail_pin_user_pages; } rc = genwqe_map_pages(cd, m->page_list, m->nr_pages, m->dma_list); @@ -618,9 +594,9 @@ int genwqe_user_vmap(struct genwqe_dev *cd, struct dma_mapping *m, void *uaddr, return 0; fail_free_user_pages: - genwqe_free_user_pages(m->page_list, m->nr_pages, m->write); + unpin_user_pages_dirty_lock(m->page_list, m->nr_pages, m->write); - fail_get_user_pages: + fail_pin_user_pages: kfree(m->page_list); m->page_list = NULL; m->dma_list = NULL; @@ -650,8 +626,8 @@ int genwqe_user_vunmap(struct genwqe_dev *cd, struct dma_mapping *m) genwqe_unmap_pages(cd, m->dma_list, m->nr_pages); if (m->page_list) { - genwqe_free_user_pages(m->page_list, m->nr_pages, m->write); - + unpin_user_pages_dirty_lock(m->page_list, m->nr_pages, + m->write); kfree(m->page_list); m->page_list = NULL; m->dma_list = NULL; base-commit: b9bbe6ed63b2b9f2c9ee5cbd0f2c946a2723f4ce -- 2.26.2
| |