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Date: Sun, 11 Aug 2019 18:50:44 -0700
From: john.hubbard@...il.com
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: Christoph Hellwig <hch@...radead.org>,
Dan Williams <dan.j.williams@...el.com>,
Dave Chinner <david@...morbit.com>,
Ira Weiny <ira.weiny@...el.com>, Jan Kara <jack@...e.cz>,
Jason Gunthorpe <jgg@...pe.ca>,
Jérôme Glisse <jglisse@...hat.com>,
LKML <linux-kernel@...r.kernel.org>, linux-mm@...ck.org,
linux-fsdevel@...r.kernel.org, linux-rdma@...r.kernel.org,
John Hubbard <jhubbard@...dia.com>
Subject: [RFC PATCH 2/2] mm/gup: introduce vaddr_pin_pages_remote()
From: John Hubbard <jhubbard@...dia.com>
This is the "vaddr_pin_pages" corresponding variant to
get_user_pages_remote(), but with FOLL_PIN semantics: the implementation
sets FOLL_PIN. That, in turn, means that the pages must ultimately be
released by put_user_page*()--typically, via vaddr_unpin_pages*().
Note that the put_user_page*() requirement won't be truly
required until all of the call sites have been converted, and
the tracking of pages is actually activated.
Also introduce vaddr_unpin_pages(), in order to have a simpler
call for the error handling cases.
Use both of these new calls in the Infiniband drive, replacing
get_user_pages_remote() and put_user_pages().
Signed-off-by: John Hubbard <jhubbard@...dia.com>
---
drivers/infiniband/core/umem_odp.c | 15 +++++----
include/linux/mm.h | 7 +++++
mm/gup.c | 50 ++++++++++++++++++++++++++++++
3 files changed, 66 insertions(+), 6 deletions(-)
diff --git a/drivers/infiniband/core/umem_odp.c b/drivers/infiniband/core/umem_odp.c
index 53085896d718..fdff034a8a30 100644
--- a/drivers/infiniband/core/umem_odp.c
+++ b/drivers/infiniband/core/umem_odp.c
@@ -534,7 +534,7 @@ static int ib_umem_odp_map_dma_single_page(
}
out:
- put_user_page(page);
+ vaddr_unpin_pages(&page, 1, &umem_odp->umem.vaddr_pin);
if (remove_existing_mapping) {
ib_umem_notifier_start_account(umem_odp);
@@ -635,9 +635,10 @@ int ib_umem_odp_map_dma_pages(struct ib_umem_odp *umem_odp, u64 user_virt,
* complex (and doesn't gain us much performance in most use
* cases).
*/
- npages = get_user_pages_remote(owning_process, owning_mm,
+ npages = vaddr_pin_pages_remote(owning_process, owning_mm,
user_virt, gup_num_pages,
- flags, local_page_list, NULL, NULL);
+ flags, local_page_list, NULL, NULL,
+ &umem_odp->umem.vaddr_pin);
up_read(&owning_mm->mmap_sem);
if (npages < 0) {
@@ -657,7 +658,8 @@ int ib_umem_odp_map_dma_pages(struct ib_umem_odp *umem_odp, u64 user_virt,
ret = -EFAULT;
break;
}
- put_user_page(local_page_list[j]);
+ vaddr_unpin_pages(&local_page_list[j], 1,
+ &umem_odp->umem.vaddr_pin);
continue;
}
@@ -684,8 +686,9 @@ int ib_umem_odp_map_dma_pages(struct ib_umem_odp *umem_odp, u64 user_virt,
* ib_umem_odp_map_dma_single_page().
*/
if (npages - (j + 1) > 0)
- put_user_pages(&local_page_list[j+1],
- npages - (j + 1));
+ vaddr_unpin_pages(&local_page_list[j+1],
+ npages - (j + 1),
+ &umem_odp->umem.vaddr_pin);
break;
}
}
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 61b616cd9243..2bd76ad8787e 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1606,6 +1606,13 @@ int __account_locked_vm(struct mm_struct *mm, unsigned long pages, bool inc,
long vaddr_pin_pages(unsigned long addr, unsigned long nr_pages,
unsigned int gup_flags, struct page **pages,
struct vaddr_pin *vaddr_pin);
+long vaddr_pin_pages_remote(struct task_struct *tsk, struct mm_struct *mm,
+ unsigned long start, unsigned long nr_pages,
+ unsigned int gup_flags, struct page **pages,
+ struct vm_area_struct **vmas, int *locked,
+ struct vaddr_pin *vaddr_pin);
+void vaddr_unpin_pages(struct page **pages, unsigned long nr_pages,
+ struct vaddr_pin *vaddr_pin);
void vaddr_unpin_pages_dirty_lock(struct page **pages, unsigned long nr_pages,
struct vaddr_pin *vaddr_pin, bool make_dirty);
bool mapping_inode_has_layout(struct vaddr_pin *vaddr_pin, struct page *page);
diff --git a/mm/gup.c b/mm/gup.c
index 85f09958fbdc..bb95adfaf9b6 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -2518,6 +2518,38 @@ long vaddr_pin_pages(unsigned long addr, unsigned long nr_pages,
}
EXPORT_SYMBOL(vaddr_pin_pages);
+/**
+ * vaddr_pin_pages pin pages by virtual address and return the pages to the
+ * user.
+ *
+ * @tsk: the task_struct to use for page fault accounting, or
+ * NULL if faults are not to be recorded.
+ * @mm: mm_struct of target mm
+ * @addr: start address
+ * @nr_pages: number of pages to pin
+ * @gup_flags: flags to use for the pin
+ * @pages: array of pages returned
+ * @vaddr_pin: initialized meta information this pin is to be associated
+ * with.
+ *
+ * This is the "vaddr_pin_pages" corresponding variant to
+ * get_user_pages_remote(), but with FOLL_PIN semantics: the implementation sets
+ * FOLL_PIN. That, in turn, means that the pages must ultimately be released
+ * by put_user_page().
+ */
+long vaddr_pin_pages_remote(struct task_struct *tsk, struct mm_struct *mm,
+ unsigned long start, unsigned long nr_pages,
+ unsigned int gup_flags, struct page **pages,
+ struct vm_area_struct **vmas, int *locked,
+ struct vaddr_pin *vaddr_pin)
+{
+ gup_flags |= FOLL_TOUCH | FOLL_REMOTE | FOLL_PIN;
+
+ return __get_user_pages_locked(tsk, mm, start, nr_pages, pages, vmas,
+ locked, gup_flags, vaddr_pin);
+}
+EXPORT_SYMBOL(vaddr_pin_pages_remote);
+
/**
* vaddr_unpin_pages_dirty_lock - counterpart to vaddr_pin_pages
*
@@ -2536,3 +2568,21 @@ void vaddr_unpin_pages_dirty_lock(struct page **pages, unsigned long nr_pages,
__put_user_pages_dirty_lock(vaddr_pin, pages, nr_pages, make_dirty);
}
EXPORT_SYMBOL(vaddr_unpin_pages_dirty_lock);
+
+/**
+ * vaddr_unpin_pages - simple, non-dirtying counterpart to vaddr_pin_pages
+ *
+ * @pages: array of pages returned
+ * @nr_pages: number of pages in pages
+ * @vaddr_pin: same information passed to vaddr_pin_pages
+ *
+ * Like vaddr_unpin_pages_dirty_lock, but for non-dirty pages. Useful in putting
+ * back pages in an error case: they were never made dirty.
+ */
+void vaddr_unpin_pages(struct page **pages, unsigned long nr_pages,
+ struct vaddr_pin *vaddr_pin)
+{
+ __put_user_pages_dirty_lock(vaddr_pin, pages, nr_pages, false);
+}
+EXPORT_SYMBOL(vaddr_unpin_pages);
+
--
2.22.0
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