On 2022-09-16 05:34, Yu Kuai wrote:

From: Yu Kuai <redacted>

Currently, wait_barrier() will hold 'resync_lock' to read 'conf->barrier',
and io can't be dispatched until 'barrier' is dropped.

Since holding the 'barrier' is not common, convert 'resync_lock' to use
seqlock so that holding lock can be avoided in fast path.

Signed-off-by: Yu Kuai <redacted>

Reviewed-and-Tested-by: Logan Gunthorpe [off-list ref]

So far, I've run this series 3 times through the mdadm test suite and
haven't detected any issues.

Thanks,

Logan