fscache: Add a tracepoint for cookie use/unuse

Add a tracepoint to track fscache_use/unuse_cookie().

Signed-off-by: David Howells <[email protected]>
Reviewed-by: Jeff Layton <[email protected]>
cc: [email protected]
Link: https://lore.kernel.org/r/164021588628.640689.12942919367404043608.stgit@warthog.procyon.org.uk/ # v4
2 files changed