linux-kernel - Re: [PATCH v2 2/2] dmaengine: idxd: track enabled workqueues in bitmap

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Message-ID: <e72f8966-de53-6288-517f-dd2a205a761c@intel.com>
Date:   Wed, 28 Sep 2022 08:51:56 -0700
From:   Dave Jiang <dave.jiang@...el.com>
To:     Jerry Snitselaar <jsnitsel@...hat.com>,
        linux-kernel@...r.kernel.org, dmaengine@...r.kernel.org
Cc:     Fenghua Yu <fenghua.yu@...el.com>, Vinod Koul <vkoul@...nel.org>
Subject: Re: [PATCH v2 2/2] dmaengine: idxd: track enabled workqueues in
 bitmap


On 9/28/2022 8:48 AM, Jerry Snitselaar wrote:
> Now that idxd_wq_disable_cleanup() sets the workqueue state to
> IDXD_WQ_DISABLED, use a bitmap to track which workqueues have been
> enabled. This will then be used to determine which workqueues
> should be re-enabled when attempting a software reset to recover
> from a device halt state.
>
> Cc: Fenghua Yu <fenghua.yu@...el.com>
> Cc: Dave Jiang <dave.jiang@...el.com>
> Cc: Vinod Koul <vkoul@...nel.org>
> Signed-off-by: Jerry Snitselaar <jsnitsel@...hat.com>
Reviewed-by: Dave Jiang <dave.jiang@...el.com>
> ---
> v2: Clear bit in case where idxd_wq_enable fails during re-init
>
>   drivers/dma/idxd/device.c | 2 ++
>   drivers/dma/idxd/idxd.h   | 2 ++
>   drivers/dma/idxd/init.c   | 6 ++++++
>   drivers/dma/idxd/irq.c    | 5 +++--
>   drivers/dma/idxd/sysfs.c  | 1 +
>   5 files changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/dma/idxd/device.c b/drivers/dma/idxd/device.c
> index 31911e255ac1..f0c7d6d348e3 100644
> --- a/drivers/dma/idxd/device.c
> +++ b/drivers/dma/idxd/device.c
> @@ -196,6 +196,7 @@ int idxd_wq_enable(struct idxd_wq *wq)
>   	}
>   
>   	wq->state = IDXD_WQ_ENABLED;
> +	set_bit(wq->id, idxd->wq_enable_map);
>   	dev_dbg(dev, "WQ %d enabled\n", wq->id);
>   	return 0;
>   }
> @@ -223,6 +224,7 @@ int idxd_wq_disable(struct idxd_wq *wq, bool reset_config)
>   
>   	if (reset_config)
>   		idxd_wq_disable_cleanup(wq);
> +	clear_bit(wq->id, idxd->wq_enable_map);
>   	wq->state = IDXD_WQ_DISABLED;
>   	dev_dbg(dev, "WQ %d disabled\n", wq->id);
>   	return 0;
> diff --git a/drivers/dma/idxd/idxd.h b/drivers/dma/idxd/idxd.h
> index fed0dfc1eaa8..f527a7f88b92 100644
> --- a/drivers/dma/idxd/idxd.h
> +++ b/drivers/dma/idxd/idxd.h
> @@ -11,6 +11,7 @@
>   #include <linux/idr.h>
>   #include <linux/pci.h>
>   #include <linux/ioasid.h>
> +#include <linux/bitmap.h>
>   #include <linux/perf_event.h>
>   #include <uapi/linux/idxd.h>
>   #include "registers.h"
> @@ -299,6 +300,7 @@ struct idxd_device {
>   	int rdbuf_limit;
>   	int nr_rdbufs;		/* non-reserved read buffers */
>   	unsigned int wqcfg_size;
> +	unsigned long *wq_enable_map;
>   
>   	union sw_err_reg sw_err;
>   	wait_queue_head_t cmd_waitq;
> diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
> index aa3478257ddb..7e27e69ff741 100644
> --- a/drivers/dma/idxd/init.c
> +++ b/drivers/dma/idxd/init.c
> @@ -151,6 +151,12 @@ static int idxd_setup_wqs(struct idxd_device *idxd)
>   	if (!idxd->wqs)
>   		return -ENOMEM;
>   
> +	idxd->wq_enable_map = bitmap_zalloc_node(idxd->max_wqs, GFP_KERNEL, dev_to_node(dev));
> +	if (!idxd->wq_enable_map) {
> +		kfree(idxd->wqs);
> +		return -ENOMEM;
> +	}
> +
>   	for (i = 0; i < idxd->max_wqs; i++) {
>   		wq = kzalloc_node(sizeof(*wq), GFP_KERNEL, dev_to_node(dev));
>   		if (!wq) {
> diff --git a/drivers/dma/idxd/irq.c b/drivers/dma/idxd/irq.c
> index 743ead5ebc57..3fcfbb7bf6e3 100644
> --- a/drivers/dma/idxd/irq.c
> +++ b/drivers/dma/idxd/irq.c
> @@ -49,11 +49,12 @@ static void idxd_device_reinit(struct work_struct *work)
>   		goto out;
>   
>   	for (i = 0; i < idxd->max_wqs; i++) {
> -		struct idxd_wq *wq = idxd->wqs[i];
> +		if (test_bit(i, idxd->wq_enable_map)) {
> +			struct idxd_wq *wq = idxd->wqs[i];
>   
> -		if (wq->state == IDXD_WQ_ENABLED) {
>   			rc = idxd_wq_enable(wq);
>   			if (rc < 0) {
> +				clear_bit(i, idxd->wq_enable_map);
>   				dev_warn(dev, "Unable to re-enable wq %s\n",
>   					 dev_name(wq_confdev(wq)));
>   			}
> diff --git a/drivers/dma/idxd/sysfs.c b/drivers/dma/idxd/sysfs.c
> index 3f262a57441b..3325b16ed959 100644
> --- a/drivers/dma/idxd/sysfs.c
> +++ b/drivers/dma/idxd/sysfs.c
> @@ -1405,6 +1405,7 @@ static void idxd_conf_device_release(struct device *dev)
>   	struct idxd_device *idxd = confdev_to_idxd(dev);
>   
>   	kfree(idxd->groups);
> +	bitmap_free(idxd->wq_enable_map);
>   	kfree(idxd->wqs);
>   	kfree(idxd->engines);
>   	ida_free(&idxd_ida, idxd->id);