diff options
| author | John Hubbard <jhubbard@nvidia.com> | 2020-05-17 21:13:07 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-05-19 16:46:12 +0200 |
| commit | 5459ceedb3940df460a6048762cc49d549049d6f (patch) | |
| tree | b693af059ba486f1134b7b78d0fd67227ed4dd2a /drivers/misc/mic | |
| parent | 6a0953ce7de918b06f7fed561754ad114fd964c1 (diff) | |
drivers/mic/scif: convert get_user_pages() --> pin_user_pages()
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.
Note that this effectively changes the code's behavior as well: it now
ultimately calls set_page_dirty_lock(), instead of SetPageDirty(). This
is probably more accurate.
As Christoph Hellwig put it, "set_page_dirty() is only safe if we are
dealing with a file backed page where we have reference on the inode it
hangs off." [3]
[1] Documentation/core-api/pin_user_pages.rst
[2] "Explicit pinning of user-space pages":
https://lwn.net/Articles/807108/
[3] https://lore.kernel.org/r/20190723153640.GB720@lst.de
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Link: https://lore.kernel.org/r/20200518041307.1987328-1-jhubbard@nvidia.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/misc/mic')
| -rw-r--r-- | drivers/misc/mic/scif/scif_rma.c | 26 |
1 files changed, 13 insertions, 13 deletions
diff --git a/drivers/misc/mic/scif/scif_rma.c b/drivers/misc/mic/scif/scif_rma.c index 01e27682ea30..406cd5abfa72 100644 --- a/drivers/misc/mic/scif/scif_rma.c +++ b/drivers/misc/mic/scif/scif_rma.c @@ -113,14 +113,17 @@ static int scif_destroy_pinned_pages(struct scif_pinned_pages *pin) int writeable = pin->prot & SCIF_PROT_WRITE; int kernel = SCIF_MAP_KERNEL & pin->map_flags; - for (j = 0; j < pin->nr_pages; j++) { - if (pin->pages[j] && !kernel) { - if (writeable) - SetPageDirty(pin->pages[j]); - put_page(pin->pages[j]); + if (kernel) { + for (j = 0; j < pin->nr_pages; j++) { + if (pin->pages[j] && !kernel) { + if (writeable) + set_page_dirty_lock(pin->pages[j]); + put_page(pin->pages[j]); + } } - } - + } else + unpin_user_pages_dirty_lock(pin->pages, pin->nr_pages, + writeable); scif_free(pin->pages, pin->nr_pages * sizeof(*pin->pages)); scif_free(pin, sizeof(*pin)); @@ -1375,7 +1378,7 @@ retry: } } - pinned_pages->nr_pages = get_user_pages_fast( + pinned_pages->nr_pages = pin_user_pages_fast( (u64)addr, nr_pages, (prot & SCIF_PROT_WRITE) ? FOLL_WRITE : 0, @@ -1385,11 +1388,8 @@ retry: if (ulimit) __scif_dec_pinned_vm_lock(mm, nr_pages); /* Roll back any pinned pages */ - for (i = 0; i < pinned_pages->nr_pages; i++) { - if (pinned_pages->pages[i]) - put_page( - pinned_pages->pages[i]); - } + unpin_user_pages(pinned_pages->pages, + pinned_pages->nr_pages); prot &= ~SCIF_PROT_WRITE; try_upgrade = false; goto retry; |