diff options
| author | Dave Jiang <dave.jiang@intel.com> | 2021-04-20 20:46:22 +0200 |
|---|---|---|
| committer | Vinod Koul <vkoul@kernel.org> | 2021-04-23 19:38:44 +0200 |
| commit | 93a40a6d7428921897bb7fed5ffb4ce83df05432 (patch) | |
| tree | 54abf8865fd560a524de889457748127ce5f0a0a /drivers/dma/idxd/idxd.h | |
| parent | dmaengine: idxd: remove detection of device type (diff) | |
| download | linux-93a40a6d7428921897bb7fed5ffb4ce83df05432.tar.xz linux-93a40a6d7428921897bb7fed5ffb4ce83df05432.zip | |
dmaengine: idxd: add percpu_ref to descriptor submission path
Current submission path has no way to restrict the submitter from
stop submiting on shutdown path or wq disable path. This provides a way to
quiesce the submission path.
Modeling after 'struct reqeust_queue' usage of percpu_ref. One of the
abilities of per_cpu reference counting is the ability to stop new
references from being taken while awaiting outstanding references to be
dropped. On wq shutdown, we want to block any new submissions to the kernel
workqueue and quiesce before disabling. The percpu_ref allows us to block
any new submissions and wait for any current submission calls to finish
submitting to the workqueue.
A percpu_ref is embedded in each idxd_wq context to allow control for
individual wq. The wq->wq_active counter is elevated before calling
movdir64b() or enqcmds() to submit a descriptor to the wq and dropped once
the submission call completes. The function is gated by
percpu_ref_tryget_live(). On shutdown with percpu_ref_kill() called, any
new submission would be blocked from acquiring a ref and failed. Once all
references are dropped for the wq, shutdown can continue.
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/161894438293.3202472.14894701611500822232.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Diffstat (limited to 'drivers/dma/idxd/idxd.h')
| -rw-r--r-- | drivers/dma/idxd/idxd.h | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/dma/idxd/idxd.h b/drivers/dma/idxd/idxd.h index 8055e872953c..1b539cbf3c14 100644 --- a/drivers/dma/idxd/idxd.h +++ b/drivers/dma/idxd/idxd.h @@ -108,6 +108,8 @@ struct idxd_dma_chan { struct idxd_wq { void __iomem *portal; + struct percpu_ref wq_active; + struct completion wq_dead; struct device conf_dev; struct idxd_cdev *idxd_cdev; struct wait_queue_head err_queue; @@ -395,6 +397,8 @@ void idxd_wq_unmap_portal(struct idxd_wq *wq); void idxd_wq_disable_cleanup(struct idxd_wq *wq); int idxd_wq_set_pasid(struct idxd_wq *wq, int pasid); int idxd_wq_disable_pasid(struct idxd_wq *wq); +void idxd_wq_quiesce(struct idxd_wq *wq); +int idxd_wq_init_percpu_ref(struct idxd_wq *wq); /* submission */ int idxd_submit_desc(struct idxd_wq *wq, struct idxd_desc *desc); |