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author | John Hubbard <jhubbard@nvidia.com> | 2020-05-18 07:13:07 +0300 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-05-19 17:46:12 +0300 |
commit | 5459ceedb3940df460a6048762cc49d549049d6f (patch) | |
tree | b693af059ba486f1134b7b78d0fd67227ed4dd2a /drivers/misc/genwqe | |
parent | 6a0953ce7de918b06f7fed561754ad114fd964c1 (diff) | |
download | linux-5459ceedb3940df460a6048762cc49d549049d6f.tar.xz |
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/genwqe')
0 files changed, 0 insertions, 0 deletions