drivers/IB,qib: optimize mmap_sem usage

Browse source

The driver uses mmap_sem for both pinned_vm accounting and
get_user_pages(). Because rdma drivers might want to use gup_longterm() in
the future we still need some sort of mmap_sem serialization (as opposed
to removing it entirely by using gup_fast()). Now that pinned_vm is atomic
the writer lock can therefore be converted to reader.

This also fixes a bug that __qib_get_user_pages was not taking into
account the current value of pinned_vm.

Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

...

This commit is contained in:

Davidlohr Bueso 2019-02-06 09:59:17 -08:00 • committed by Jason Gunthorpe

parent 4f564ff3d4

commit 3a2a1e9056

1 changed files with 27 additions and 46 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

73

drivers/infiniband/hw/qib/qib_user_pages.c

View file