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 <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Signed-off-by: John Hubbard <[email protected]>
---
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
