[PATCH] mm/gup: Use put_user_page*() instead of put_page*()
From: Bharath Vedartham
Date: Sun Jul 14 2019 - 15:11:38 EST
This patch converts all call sites of get_user_pages
to use put_user_page*() instead of put_page*() functions to
release reference to gup pinned pages.
This is a bunch of trivial conversions which is a part of an effort
by John Hubbard to solve issues with gup pinned pages and
filesystem writeback.
The issue is more clearly described in John Hubbard's patch[1] where
put_user_page*() functions are introduced.
Currently put_user_page*() simply does put_page but future implementations
look to change that once treewide change of put_page callsites to
put_user_page*() is finished.
The lwn article describing the issue with gup pinned pages and filesystem
writeback [2].
This patch has been tested by building and booting the kernel as I don't
have the required hardware to test the device drivers.
I did not modify gpu/drm drivers which use release_pages instead of
put_page() to release reference of gup pinned pages as I am not clear
whether release_pages and put_page are interchangable.
[1] https://lkml.org/lkml/2019/3/26/1396
[2] https://lwn.net/Articles/784574/
Signed-off-by: Bharath Vedartham <linux.bhar@xxxxxxxxx>
---
drivers/media/v4l2-core/videobuf-dma-sg.c | 3 +--
drivers/misc/sgi-gru/grufault.c | 2 +-
drivers/staging/kpc2000/kpc_dma/fileops.c | 4 +---
drivers/vfio/vfio_iommu_type1.c | 2 +-
fs/io_uring.c | 7 +++----
mm/gup_benchmark.c | 6 +-----
net/xdp/xdp_umem.c | 7 +------
7 files changed, 9 insertions(+), 22 deletions(-)
diff --git a/drivers/media/v4l2-core/videobuf-dma-sg.c b/drivers/media/v4l2-core/videobuf-dma-sg.c
index 66a6c6c..d6eeb43 100644
--- a/drivers/media/v4l2-core/videobuf-dma-sg.c
+++ b/drivers/media/v4l2-core/videobuf-dma-sg.c
@@ -349,8 +349,7 @@ int videobuf_dma_free(struct videobuf_dmabuf *dma)
BUG_ON(dma->sglen);
if (dma->pages) {
- for (i = 0; i < dma->nr_pages; i++)
- put_page(dma->pages[i]);
+ put_user_pages(dma->pages, dma->nr_pages);
kfree(dma->pages);
dma->pages = NULL;
}
diff --git a/drivers/misc/sgi-gru/grufault.c b/drivers/misc/sgi-gru/grufault.c
index 4b713a8..61b3447 100644
--- a/drivers/misc/sgi-gru/grufault.c
+++ b/drivers/misc/sgi-gru/grufault.c
@@ -188,7 +188,7 @@ static int non_atomic_pte_lookup(struct vm_area_struct *vma,
if (get_user_pages(vaddr, 1, write ? FOLL_WRITE : 0, &page, NULL) <= 0)
return -EFAULT;
*paddr = page_to_phys(page);
- put_page(page);
+ put_user_page(page);
return 0;
}
diff --git a/drivers/staging/kpc2000/kpc_dma/fileops.c b/drivers/staging/kpc2000/kpc_dma/fileops.c
index 6166587..26dceed 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:
diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index add34ad..c491524 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -369,7 +369,7 @@ static int vaddr_get_pfn(struct mm_struct *mm, unsigned long vaddr,
*/
if (ret > 0 && vma_is_fsdax(vmas[0])) {
ret = -EOPNOTSUPP;
- put_page(page[0]);
+ put_user_page(page[0]);
}
}
up_read(&mm->mmap_sem);
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 4ef62a4..b4a4549 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2694,10 +2694,9 @@ static int io_sqe_buffer_register(struct io_ring_ctx *ctx, void __user *arg,
* if we did partial map, or found file backed vmas,
* release any pages we did get
*/
- if (pret > 0) {
- for (j = 0; j < pret; j++)
- put_page(pages[j]);
- }
+ if (pret > 0)
+ put_user_pages(pages, pret);
+
if (ctx->account_mem)
io_unaccount_mem(ctx->user, nr_pages);
kvfree(imu->bvec);
diff --git a/mm/gup_benchmark.c b/mm/gup_benchmark.c
index 7dd602d..15fc7a2 100644
--- a/mm/gup_benchmark.c
+++ b/mm/gup_benchmark.c
@@ -76,11 +76,7 @@ static int __gup_benchmark_ioctl(unsigned int cmd,
gup->size = addr - gup->addr;
start_time = ktime_get();
- for (i = 0; i < nr_pages; i++) {
- if (!pages[i])
- break;
- put_page(pages[i]);
- }
+ put_user_pages(pages, nr_pages);
end_time = ktime_get();
gup->put_delta_usec = ktime_us_delta(end_time, start_time);
diff --git a/net/xdp/xdp_umem.c b/net/xdp/xdp_umem.c
index 9c6de4f..6103e19 100644
--- a/net/xdp/xdp_umem.c
+++ b/net/xdp/xdp_umem.c
@@ -173,12 +173,7 @@ static void xdp_umem_unpin_pages(struct xdp_umem *umem)
{
unsigned int i;
- for (i = 0; i < umem->npgs; i++) {
- struct page *page = umem->pgs[i];
-
- set_page_dirty_lock(page);
- put_page(page);
- }
+ put_user_pages_dirty_lock(umem->pgs, umem->npgs);
kfree(umem->pgs);
umem->pgs = NULL;
--
1.8.3.1