From: Tejun Heo Date: Wed, 24 Sep 2014 17:31:50 +0000 (-0400) Subject: percpu_ref: add PERCPU_REF_INIT_* flags X-Git-Tag: fixes-against-v3.18-rc2~134^2~3 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2aad2a86f6685c10360ec8a5a55eb9ab7059cb72;p=pandora-kernel.git percpu_ref: add PERCPU_REF_INIT_* flags With the recent addition of percpu_ref_reinit(), percpu_ref now can be used as a persistent switch which can be turned on and off repeatedly where turning off maps to killing the ref and waiting for it to drain; however, there currently isn't a way to initialize a percpu_ref in its off (killed and drained) state, which can be inconvenient for certain persistent switch use cases. Similarly, percpu_ref_switch_to_atomic/percpu() allow dynamic selection of operation mode; however, currently a newly initialized percpu_ref is always in percpu mode making it impossible to avoid the latency overhead of switching to atomic mode. This patch adds @flags to percpu_ref_init() and implements the following flags. * PERCPU_REF_INIT_ATOMIC : start ref in atomic mode * PERCPU_REF_INIT_DEAD : start ref killed and drained These flags should be able to serve the above two use cases. v2: target_core_tpg.c conversion was missing. Fixed. Signed-off-by: Tejun Heo Reviewed-by: Kent Overstreet Cc: Jens Axboe Cc: Christoph Hellwig Cc: Johannes Weiner --- Reading git-diff-tree failed