[SRU][B][F][G][PATCH 0/1] dm crypt: add flags to optionally

[Gerald Yang]

BugLink: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1910976

=== SRU Justification ===
[Impact]
To get better performance for dm-crypt in some cases, bypass kcryptd
workqueue can reduce the overhead in context switch between kworkers,
cherry-pick commit 39d42fa96ba1b7d2544db3f8ed5da8fb0d5cb877 from mainline
kernel, and bypass kcryptd workqueue is not enabled by default

[Fix]
Add flags to bypass kcryptd workqueue

[Test]
create dm-crypt and setup DM_CRYPT_NO_READ_WORKQUEUE and
DM_CRYPT_NO_WRITE_WORKQUEUE, read/write data and run perf record to see
if read/write to the encrypted device will bypass kcryptd workqueue

[Regression Potential]
Low, this feature is disabled by default, need to enable manually

Ignat Korchagin (1):
  dm crypt: add flags to optionally bypass kcryptd workqueues

 drivers/md/dm-crypt.c | 50 ++++++++++++++++++++++++++++++++++++-------
 1 file changed, 42 insertions(+), 8 deletions(-)

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2.25.1