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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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5459ceedb3
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>
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| .. | ||
| Makefile | ||
| scif_api.c | ||
| scif_debugfs.c | ||
| scif_dma.c | ||
| scif_epd.c | ||
| scif_epd.h | ||
| scif_fd.c | ||
| scif_fence.c | ||
| scif_main.c | ||
| scif_main.h | ||
| scif_map.h | ||
| scif_mmap.c | ||
| scif_nm.c | ||
| scif_nodeqp.c | ||
| scif_nodeqp.h | ||
| scif_peer_bus.c | ||
| scif_peer_bus.h | ||
| scif_ports.c | ||
| scif_rb.c | ||
| scif_rb.h | ||
| scif_rma_list.c | ||
| scif_rma_list.h | ||
| scif_rma.c | ||
| scif_rma.h | ||