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author | 2024-03-12 20:24:21 -0600 | |
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committer | 2024-04-15 08:10:26 -0600 | |
commit | 87585b05757dc70545efb434669708d276125559 (patch) | |
tree | d3020002d23692f431baf61797e51d439312950f /samples/kprobes/kretprobe_example.c | |
parent | io_uring/kbuf: vmap pinned buffer ring (diff) | |
download | linux-87585b05757dc70545efb434669708d276125559.tar.gz linux-87585b05757dc70545efb434669708d276125559.tar.bz2 linux-87585b05757dc70545efb434669708d276125559.zip |
io_uring/kbuf: use vm_insert_pages() for mmap'ed pbuf ring
Rather than use remap_pfn_range() for this and manually free later,
switch to using vm_insert_page() and have it Just Work.
This requires a bit of effort on the mmap lookup side, as the ctx
uring_lock isn't held, which otherwise protects buffer_lists from being
torn down, and it's not safe to grab from mmap context that would
introduce an ABBA deadlock between the mmap lock and the ctx uring_lock.
Instead, lookup the buffer_list under RCU, as the the list is RCU freed
already. Use the existing reference count to determine whether it's
possible to safely grab a reference to it (eg if it's not zero already),
and drop that reference when done with the mapping. If the mmap
reference is the last one, the buffer_list and the associated memory can
go away, since the vma insertion has references to the inserted pages at
that point.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'samples/kprobes/kretprobe_example.c')
0 files changed, 0 insertions, 0 deletions