* [PATCH v4 1/3] mm/gup: add make_dirty arg to put_user_pages_dirty_lock()
2019-07-30 20:57 [PATCH v4 0/3] mm/gup: add make_dirty arg to put_user_pages_dirty_lock() john.hubbard
@ 2019-07-30 20:57 ` john.hubbard
2019-08-01 6:07 ` Christoph Hellwig
2019-07-30 20:57 ` [PATCH v4 2/3] drivers/gpu/drm/via: convert put_page() to put_user_page*() john.hubbard
2019-07-30 20:57 ` [PATCH v4 3/3] net/xdp: " john.hubbard
2 siblings, 1 reply; 9+ messages in thread
From: john.hubbard @ 2019-07-30 20:57 UTC (permalink / raw)
To: Andrew Morton
Cc: Al Viro, Christian Benvenuti, Christoph Hellwig, Dan Williams,
Darrick J . Wong, Dave Chinner, Ira Weiny, Jan Kara,
Jason Gunthorpe, Jens Axboe, Jerome Glisse, Kirill A . Shutemov,
Matthew Wilcox, Michal Hocko, Mike Marciniszyn, Mike Rapoport,
linux-block, linux-fsdevel, linux-mm, linux-xfs, LKML,
John Hubbard, Christoph Hellwig
From: John Hubbard <jhubbard@nvidia.com>
Provide more capable variation of put_user_pages_dirty_lock(),
and delete put_user_pages_dirty(). This is based on the
following:
1. Lots of call sites become simpler if a bool is passed
into put_user_page*(), instead of making the call site
choose which put_user_page*() variant to call.
2. Christoph Hellwig's observation that set_page_dirty_lock()
is usually correct, and set_page_dirty() is usually a
bug, or at least questionable, within a put_user_page*()
calling chain.
This leads to the following API choices:
* put_user_pages_dirty_lock(page, npages, make_dirty)
* There is no put_user_pages_dirty(). You have to
hand code that, in the rare case that it's
required.
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
---
drivers/infiniband/core/umem.c | 5 +-
drivers/infiniband/hw/hfi1/user_pages.c | 5 +-
drivers/infiniband/hw/qib/qib_user_pages.c | 5 +-
drivers/infiniband/hw/usnic/usnic_uiom.c | 5 +-
drivers/infiniband/sw/siw/siw_mem.c | 10 +-
include/linux/mm.h | 5 +-
mm/gup.c | 115 +++++++++------------
7 files changed, 58 insertions(+), 92 deletions(-)
diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c
index 08da840ed7ee..965cf9dea71a 100644
--- a/drivers/infiniband/core/umem.c
+++ b/drivers/infiniband/core/umem.c
@@ -54,10 +54,7 @@ static void __ib_umem_release(struct ib_device *dev, struct ib_umem *umem, int d
for_each_sg_page(umem->sg_head.sgl, &sg_iter, umem->sg_nents, 0) {
page = sg_page_iter_page(&sg_iter);
- if (umem->writable && dirty)
- put_user_pages_dirty_lock(&page, 1);
- else
- put_user_page(page);
+ put_user_pages_dirty_lock(&page, 1, umem->writable && dirty);
}
sg_free_table(&umem->sg_head);
diff --git a/drivers/infiniband/hw/hfi1/user_pages.c b/drivers/infiniband/hw/hfi1/user_pages.c
index b89a9b9aef7a..469acb961fbd 100644
--- a/drivers/infiniband/hw/hfi1/user_pages.c
+++ b/drivers/infiniband/hw/hfi1/user_pages.c
@@ -118,10 +118,7 @@ int hfi1_acquire_user_pages(struct mm_struct *mm, unsigned long vaddr, size_t np
void hfi1_release_user_pages(struct mm_struct *mm, struct page **p,
size_t npages, bool dirty)
{
- if (dirty)
- put_user_pages_dirty_lock(p, npages);
- else
- put_user_pages(p, npages);
+ put_user_pages_dirty_lock(p, npages, dirty);
if (mm) { /* during close after signal, mm can be NULL */
atomic64_sub(npages, &mm->pinned_vm);
diff --git a/drivers/infiniband/hw/qib/qib_user_pages.c b/drivers/infiniband/hw/qib/qib_user_pages.c
index bfbfbb7e0ff4..6bf764e41891 100644
--- a/drivers/infiniband/hw/qib/qib_user_pages.c
+++ b/drivers/infiniband/hw/qib/qib_user_pages.c
@@ -40,10 +40,7 @@
static void __qib_release_user_pages(struct page **p, size_t num_pages,
int dirty)
{
- if (dirty)
- put_user_pages_dirty_lock(p, num_pages);
- else
- put_user_pages(p, num_pages);
+ put_user_pages_dirty_lock(p, num_pages, dirty);
}
/**
diff --git a/drivers/infiniband/hw/usnic/usnic_uiom.c b/drivers/infiniband/hw/usnic/usnic_uiom.c
index 0b0237d41613..62e6ffa9ad78 100644
--- a/drivers/infiniband/hw/usnic/usnic_uiom.c
+++ b/drivers/infiniband/hw/usnic/usnic_uiom.c
@@ -75,10 +75,7 @@ static void usnic_uiom_put_pages(struct list_head *chunk_list, int dirty)
for_each_sg(chunk->page_list, sg, chunk->nents, i) {
page = sg_page(sg);
pa = sg_phys(sg);
- if (dirty)
- put_user_pages_dirty_lock(&page, 1);
- else
- put_user_page(page);
+ put_user_pages_dirty_lock(&page, 1, dirty);
usnic_dbg("pa: %pa\n", &pa);
}
kfree(chunk);
diff --git a/drivers/infiniband/sw/siw/siw_mem.c b/drivers/infiniband/sw/siw/siw_mem.c
index 67171c82b0c4..ab83a9cec562 100644
--- a/drivers/infiniband/sw/siw/siw_mem.c
+++ b/drivers/infiniband/sw/siw/siw_mem.c
@@ -63,15 +63,7 @@ struct siw_mem *siw_mem_id2obj(struct siw_device *sdev, int stag_index)
static void siw_free_plist(struct siw_page_chunk *chunk, int num_pages,
bool dirty)
{
- struct page **p = chunk->plist;
-
- while (num_pages--) {
- if (!PageDirty(*p) && dirty)
- put_user_pages_dirty_lock(p, 1);
- else
- put_user_page(*p);
- p++;
- }
+ put_user_pages_dirty_lock(chunk->plist, num_pages, dirty);
}
void siw_umem_release(struct siw_umem *umem, bool dirty)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 0334ca97c584..9759b6a24420 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1057,8 +1057,9 @@ static inline void put_user_page(struct page *page)
put_page(page);
}
-void put_user_pages_dirty(struct page **pages, unsigned long npages);
-void put_user_pages_dirty_lock(struct page **pages, unsigned long npages);
+void put_user_pages_dirty_lock(struct page **pages, unsigned long npages,
+ bool make_dirty);
+
void put_user_pages(struct page **pages, unsigned long npages);
#if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
diff --git a/mm/gup.c b/mm/gup.c
index 98f13ab37bac..7fefd7ab02c4 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -29,85 +29,70 @@ struct follow_page_context {
unsigned int page_mask;
};
-typedef int (*set_dirty_func_t)(struct page *page);
-
-static void __put_user_pages_dirty(struct page **pages,
- unsigned long npages,
- set_dirty_func_t sdf)
-{
- unsigned long index;
-
- for (index = 0; index < npages; index++) {
- struct page *page = compound_head(pages[index]);
-
- /*
- * Checking PageDirty at this point may race with
- * clear_page_dirty_for_io(), but that's OK. Two key cases:
- *
- * 1) This code sees the page as already dirty, so it skips
- * the call to sdf(). That could happen because
- * clear_page_dirty_for_io() called page_mkclean(),
- * followed by set_page_dirty(). However, now the page is
- * going to get written back, which meets the original
- * intention of setting it dirty, so all is well:
- * clear_page_dirty_for_io() goes on to call
- * TestClearPageDirty(), and write the page back.
- *
- * 2) This code sees the page as clean, so it calls sdf().
- * The page stays dirty, despite being written back, so it
- * gets written back again in the next writeback cycle.
- * This is harmless.
- */
- if (!PageDirty(page))
- sdf(page);
-
- put_user_page(page);
- }
-}
-
/**
- * put_user_pages_dirty() - release and dirty an array of gup-pinned pages
- * @pages: array of pages to be marked dirty and released.
+ * put_user_pages_dirty_lock() - release and optionally dirty gup-pinned pages
+ * @pages: array of pages to be maybe marked dirty, and definitely released.
* @npages: number of pages in the @pages array.
+ * @make_dirty: whether to mark the pages dirty
*
* "gup-pinned page" refers to a page that has had one of the get_user_pages()
* variants called on that page.
*
* For each page in the @pages array, make that page (or its head page, if a
- * compound page) dirty, if it was previously listed as clean. Then, release
- * the page using put_user_page().
+ * compound page) dirty, if @make_dirty is true, and if the page was previously
+ * listed as clean. In any case, releases all pages using put_user_page(),
+ * possibly via put_user_pages(), for the non-dirty case.
*
* Please see the put_user_page() documentation for details.
*
- * set_page_dirty(), which does not lock the page, is used here.
- * Therefore, it is the caller's responsibility to ensure that this is
- * safe. If not, then put_user_pages_dirty_lock() should be called instead.
+ * set_page_dirty_lock() is used internally. If instead, set_page_dirty() is
+ * required, then the caller should a) verify that this is really correct,
+ * because _lock() is usually required, and b) hand code it:
+ * set_page_dirty_lock(), put_user_page().
*
*/
-void put_user_pages_dirty(struct page **pages, unsigned long npages)
+void put_user_pages_dirty_lock(struct page **pages, unsigned long npages,
+ bool make_dirty)
{
- __put_user_pages_dirty(pages, npages, set_page_dirty);
-}
-EXPORT_SYMBOL(put_user_pages_dirty);
+ unsigned long index;
-/**
- * put_user_pages_dirty_lock() - release and dirty an array of gup-pinned pages
- * @pages: array of pages to be marked dirty and released.
- * @npages: number of pages in the @pages array.
- *
- * For each page in the @pages array, make that page (or its head page, if a
- * compound page) dirty, if it was previously listed as clean. Then, release
- * the page using put_user_page().
- *
- * Please see the put_user_page() documentation for details.
- *
- * This is just like put_user_pages_dirty(), except that it invokes
- * set_page_dirty_lock(), instead of set_page_dirty().
- *
- */
-void put_user_pages_dirty_lock(struct page **pages, unsigned long npages)
-{
- __put_user_pages_dirty(pages, npages, set_page_dirty_lock);
+ /*
+ * TODO: this can be optimized for huge pages: if a series of pages is
+ * physically contiguous and part of the same compound page, then a
+ * single operation to the head page should suffice.
+ */
+
+ if (!make_dirty) {
+ put_user_pages(pages, npages);
+ return;
+ }
+
+ for (index = 0; index < npages; index++) {
+ struct page *page = compound_head(pages[index]);
+ /*
+ * Checking PageDirty at this point may race with
+ * clear_page_dirty_for_io(), but that's OK. Two key
+ * cases:
+ *
+ * 1) This code sees the page as already dirty, so it
+ * skips the call to set_page_dirty(). That could happen
+ * because clear_page_dirty_for_io() called
+ * page_mkclean(), followed by set_page_dirty().
+ * However, now the page is going to get written back,
+ * which meets the original intention of setting it
+ * dirty, so all is well: clear_page_dirty_for_io() goes
+ * on to call TestClearPageDirty(), and write the page
+ * back.
+ *
+ * 2) This code sees the page as clean, so it calls
+ * set_page_dirty(). The page stays dirty, despite being
+ * written back, so it gets written back again in the
+ * next writeback cycle. This is harmless.
+ */
+ if (!PageDirty(page))
+ set_page_dirty_lock(page);
+ put_user_page(page);
+ }
}
EXPORT_SYMBOL(put_user_pages_dirty_lock);
--
2.22.0
^ permalink raw reply related [flat|nested] 9+ messages in thread
* [PATCH v4 2/3] drivers/gpu/drm/via: convert put_page() to put_user_page*()
2019-07-30 20:57 [PATCH v4 0/3] mm/gup: add make_dirty arg to put_user_pages_dirty_lock() john.hubbard
2019-07-30 20:57 ` [PATCH v4 1/3] " john.hubbard
@ 2019-07-30 20:57 ` john.hubbard
2019-07-30 20:57 ` [PATCH v4 3/3] net/xdp: " john.hubbard
2 siblings, 0 replies; 9+ messages in thread
From: john.hubbard @ 2019-07-30 20:57 UTC (permalink / raw)
To: Andrew Morton
Cc: Al Viro, Christian Benvenuti, Christoph Hellwig, Dan Williams,
Darrick J . Wong, Dave Chinner, Ira Weiny, Jan Kara,
Jason Gunthorpe, Jens Axboe, Jerome Glisse, Kirill A . Shutemov,
Matthew Wilcox, Michal Hocko, Mike Marciniszyn, Mike Rapoport,
linux-block, linux-fsdevel, linux-mm, linux-xfs, LKML,
John Hubbard, David Airlie, Daniel Vetter, dri-devel
From: John Hubbard <jhubbard@nvidia.com>
For pages that were retained via get_user_pages*(), release those pages
via the new put_user_page*() routines, instead of via put_page() or
release_pages().
This is part a tree-wide conversion, as described in commit fc1d8e7cca2d
("mm: introduce put_user_page*(), placeholder versions").
Also reverse the order of a comparison, in order to placate
checkpatch.pl.
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
---
drivers/gpu/drm/via/via_dmablit.c | 10 ++--------
1 file changed, 2 insertions(+), 8 deletions(-)
diff --git a/drivers/gpu/drm/via/via_dmablit.c b/drivers/gpu/drm/via/via_dmablit.c
index 062067438f1d..b5b5bf0ba65e 100644
--- a/drivers/gpu/drm/via/via_dmablit.c
+++ b/drivers/gpu/drm/via/via_dmablit.c
@@ -171,7 +171,6 @@ via_map_blit_for_device(struct pci_dev *pdev,
static void
via_free_sg_info(struct pci_dev *pdev, drm_via_sg_info_t *vsg)
{
- struct page *page;
int i;
switch (vsg->state) {
@@ -186,13 +185,8 @@ via_free_sg_info(struct pci_dev *pdev, drm_via_sg_info_t *vsg)
kfree(vsg->desc_pages);
/* fall through */
case dr_via_pages_locked:
- for (i = 0; i < vsg->num_pages; ++i) {
- if (NULL != (page = vsg->pages[i])) {
- if (!PageReserved(page) && (DMA_FROM_DEVICE == vsg->direction))
- SetPageDirty(page);
- put_page(page);
- }
- }
+ put_user_pages_dirty_lock(vsg->pages, vsg->num_pages,
+ (vsg->direction == DMA_FROM_DEVICE));
/* fall through */
case dr_via_pages_alloc:
vfree(vsg->pages);
--
2.22.0
^ permalink raw reply related [flat|nested] 9+ messages in thread
* [PATCH v4 3/3] net/xdp: convert put_page() to put_user_page*()
2019-07-30 20:57 [PATCH v4 0/3] mm/gup: add make_dirty arg to put_user_pages_dirty_lock() john.hubbard
2019-07-30 20:57 ` [PATCH v4 1/3] " john.hubbard
2019-07-30 20:57 ` [PATCH v4 2/3] drivers/gpu/drm/via: convert put_page() to put_user_page*() john.hubbard
@ 2019-07-30 20:57 ` john.hubbard
2019-07-31 6:08 ` Björn Töpel
2 siblings, 1 reply; 9+ messages in thread
From: john.hubbard @ 2019-07-30 20:57 UTC (permalink / raw)
To: Andrew Morton
Cc: Al Viro, Christian Benvenuti, Christoph Hellwig, Dan Williams,
Darrick J . Wong, Dave Chinner, Ira Weiny, Jan Kara,
Jason Gunthorpe, Jens Axboe, Jerome Glisse, Kirill A . Shutemov,
Matthew Wilcox, Michal Hocko, Mike Marciniszyn, Mike Rapoport,
linux-block, linux-fsdevel, linux-mm, linux-xfs, LKML,
John Hubbard, Björn Töpel, Magnus Karlsson,
David S . Miller, netdev
From: John Hubbard <jhubbard@nvidia.com>
For pages that were retained via get_user_pages*(), release those pages
via the new put_user_page*() routines, instead of via put_page() or
release_pages().
This is part a tree-wide conversion, as described in commit fc1d8e7cca2d
("mm: introduce put_user_page*(), placeholder versions").
Cc: Björn Töpel <bjorn.topel@intel.com>
Cc: Magnus Karlsson <magnus.karlsson@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: netdev@vger.kernel.org
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
---
net/xdp/xdp_umem.c | 9 +--------
1 file changed, 1 insertion(+), 8 deletions(-)
diff --git a/net/xdp/xdp_umem.c b/net/xdp/xdp_umem.c
index 83de74ca729a..17c4b3d3dc34 100644
--- a/net/xdp/xdp_umem.c
+++ b/net/xdp/xdp_umem.c
@@ -166,14 +166,7 @@ void xdp_umem_clear_dev(struct xdp_umem *umem)
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, true);
kfree(umem->pgs);
umem->pgs = NULL;
--
2.22.0
^ permalink raw reply related [flat|nested] 9+ messages in thread