Re: [PATCH 3/5] dmaengine: idxd: Add idxd_device_config_save() and idxd_device_config_restore() helpers

[Dave Jiang]

On 7/5/24 11:15 AM, Fenghua Yu wrote:
> Add the helpers to save and restore IDXD device configurations.
> 
> These helpers will be called during Function Level Reset (FLR) processing.
> 
> Signed-off-by: Fenghua Yu <fenghua.yu@xxxxxxxxx>
> ---
>  drivers/dma/idxd/idxd.h |  11 ++
>  drivers/dma/idxd/init.c | 224 ++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 235 insertions(+)
> 
> diff --git a/drivers/dma/idxd/idxd.h b/drivers/dma/idxd/idxd.h
> index 03f099518ec1..4f3e98720b45 100644
> --- a/drivers/dma/idxd/idxd.h
> +++ b/drivers/dma/idxd/idxd.h
> @@ -377,6 +377,17 @@ struct idxd_device {
>  	struct dentry *dbgfs_evl_file;
>  
>  	bool user_submission_safe;
> +
> +	struct idxd_saved_states *idxd_saved;
> +};
> +
> +struct idxd_saved_states {
> +	struct idxd_device saved_idxd;
> +	struct idxd_evl saved_evl;
> +	struct idxd_engine **saved_engines;
> +	struct idxd_wq **saved_wqs;
> +	struct idxd_group **saved_groups;
> +	unsigned long *saved_wq_enable_map;
>  };
>  
>  static inline unsigned int evl_ent_size(struct idxd_device *idxd)
> diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
> index a6d8097b2dcf..bb03d8cc5d32 100644
> --- a/drivers/dma/idxd/init.c
> +++ b/drivers/dma/idxd/init.c
> @@ -749,6 +749,230 @@ static void idxd_unbind(struct device_driver *drv, const char *buf)
>  	put_device(dev);
>  }
>  
> +/* Free allocated saved wq enable map after saving wq configs. */
> +static void free_saved_wq_enable_map(unsigned long *map)
> +{
> +	bitmap_free(map);
> +}
> +
> +DEFINE_FREE(free_saved_wq_enable_map, unsigned long *, if (!IS_ERR_OR_NULL(_T))
> +	    free_saved_wq_enable_map(_T))
> +
> +#define idxd_free_saved_configs(saved_configs, count)	\
> +	do {						\
> +		int i;					\
> +							\
> +		for (i = 0; i < (count); i++)		\
> +			kfree(saved_configs[i]);	\
> +	} while (0)
> +
> +/*
> + * Save IDXD device configurations including engines, groups, wqs etc.
> + * The saved configurations can be restored when needed.
> + */
> +static int idxd_device_config_save(struct idxd_device *idxd,
> +				   struct idxd_saved_states *idxd_saved)
> +{
> +	struct device *dev = &idxd->pdev->dev;
> +	int i;
> +
> +	memcpy(&idxd_saved->saved_idxd, idxd, sizeof(*idxd));
> +
> +	if (idxd->evl) {
> +		memcpy(&idxd_saved->saved_evl, idxd->evl,
> +		       sizeof(struct idxd_evl));
> +	}
> +
> +	struct idxd_group **saved_groups __free(kfree) =
> +			kcalloc_node(idxd->max_groups,
> +				     sizeof(struct idxd_group *),
> +				     GFP_KERNEL, dev_to_node(dev));
> +	if (!saved_groups)
> +		return -ENOMEM;
> +
> +	for (i = 0; i < idxd->max_groups; i++) {
> +		struct idxd_group *saved_group __free(kfree) =
> +			kzalloc_node(sizeof(*saved_group), GFP_KERNEL,
> +				     dev_to_node(dev));
> +
> +		if (!saved_group) {
> +			idxd_free_saved_configs(saved_groups, i);
> +
> +			return -ENOMEM;
> +		}
> +
> +		memcpy(saved_group, idxd->groups[i], sizeof(*saved_group));
> +		saved_groups[i] = no_free_ptr(saved_group);
> +	}
> +
> +	struct idxd_engine **saved_engines =
> +			kcalloc_node(idxd->max_engines,
> +				     sizeof(struct idxd_engine *),
> +				     GFP_KERNEL, dev_to_node(dev));
> +	if (!saved_engines) {
> +		/* Free saved groups */
> +		idxd_free_saved_configs(saved_groups, idxd->max_groups);

I would put a wrapper function around idxd_device_config_save(). If error is returned from idxd_device_config_save(), then you can just call the cleanup function and free everything allocated. That way you don't need to keep calling idxd_free_saved_configs() for every error exit point.

DJ

> +
> +		return -ENOMEM;
> +	}
> +	for (i = 0; i < idxd->max_engines; i++) {
> +		struct idxd_engine *saved_engine __free(kfree) =
> +				kzalloc_node(sizeof(*saved_engine), GFP_KERNEL,
> +					     dev_to_node(dev));
> +		if (!saved_engine) {
> +			/* Free saved groups and engines */
> +			idxd_free_saved_configs(saved_groups, idxd->max_groups);
> +			idxd_free_saved_configs(saved_engines, i);
> +
> +			return -ENOMEM;
> +		}
> +
> +		memcpy(saved_engine, idxd->engines[i], sizeof(*saved_engine));
> +		saved_engines[i] = no_free_ptr(saved_engine);
> +	}
> +
> +	unsigned long *saved_wq_enable_map __free(free_saved_wq_enable_map) =
> +			bitmap_zalloc_node(idxd->max_wqs, GFP_KERNEL,
> +					   dev_to_node(dev));
> +	if (!saved_wq_enable_map) {
> +		/* Free saved groups and engines */
> +		idxd_free_saved_configs(saved_groups, idxd->max_groups);
> +		idxd_free_saved_configs(saved_engines, idxd->max_engines);
> +
> +		return -ENOMEM;
> +	}
> +
> +	bitmap_copy(saved_wq_enable_map, idxd->wq_enable_map, idxd->max_wqs);
> +
> +	struct idxd_wq **saved_wqs __free(kfree) =
> +			kcalloc_node(idxd->max_wqs, sizeof(struct idxd_wq *),
> +				     GFP_KERNEL, dev_to_node(dev));
> +	if (!saved_wqs) {
> +		/* Free saved groups and engines */
> +		idxd_free_saved_configs(saved_groups, idxd->max_groups);
> +		idxd_free_saved_configs(saved_engines, idxd->max_engines);
> +
> +		return -ENOMEM;
> +	}
> +
> +	for (i = 0; i < idxd->max_wqs; i++) {
> +		struct idxd_wq *saved_wq __free(kfree) =
> +			kzalloc_node(sizeof(*saved_wq), GFP_KERNEL,
> +				     dev_to_node(dev));
> +		struct idxd_wq *wq;
> +
> +		if (!saved_wq) {
> +			/* Free saved groups, engines, and wqs */
> +			idxd_free_saved_configs(saved_groups, idxd->max_groups);
> +			idxd_free_saved_configs(saved_engines,
> +						idxd->max_engines);
> +			idxd_free_saved_configs(saved_wqs, i);
> +
> +			return -ENOMEM;
> +		}
> +
> +		if (!test_bit(i, saved_wq_enable_map))
> +			continue;
> +
> +		wq = idxd->wqs[i];
> +		mutex_lock(&wq->wq_lock);
> +		memcpy(saved_wq, wq, sizeof(*saved_wq));
> +		saved_wqs[i] = no_free_ptr(saved_wq);
> +		mutex_unlock(&wq->wq_lock);
> +	}
> +
> +	/* Save configurations */
> +	idxd_saved->saved_groups = no_free_ptr(saved_groups);
> +	idxd_saved->saved_engines = no_free_ptr(saved_engines);
> +	idxd_saved->saved_wq_enable_map = no_free_ptr(saved_wq_enable_map);
> +	idxd_saved->saved_wqs = no_free_ptr(saved_wqs);
> +
> +	return 0;
> +}
> +
> +/*
> + * Restore IDXD device configurations including engines, groups, wqs etc
> + * that were saved before.
> + */
> +static void idxd_device_config_restore(struct idxd_device *idxd,
> +				       struct idxd_saved_states *idxd_saved)
> +{
> +	struct idxd_evl *saved_evl = &idxd_saved->saved_evl;
> +	int i;
> +
> +	idxd->rdbuf_limit = idxd_saved->saved_idxd.rdbuf_limit;
> +
> +	if (saved_evl)
> +		idxd->evl->size = saved_evl->size;
> +
> +	for (i = 0; i < idxd->max_groups; i++) {
> +		struct idxd_group *saved_group, *group;
> +
> +		saved_group = idxd_saved->saved_groups[i];
> +		group = idxd->groups[i];
> +
> +		group->rdbufs_allowed = saved_group->rdbufs_allowed;
> +		group->rdbufs_reserved = saved_group->rdbufs_reserved;
> +		group->tc_a = saved_group->tc_a;
> +		group->tc_b = saved_group->tc_b;
> +		group->use_rdbuf_limit = saved_group->use_rdbuf_limit;
> +
> +		kfree(saved_group);
> +	}
> +	kfree(idxd_saved->saved_groups);
> +
> +	for (i = 0; i < idxd->max_engines; i++) {
> +		struct idxd_engine *saved_engine, *engine;
> +
> +		saved_engine = idxd_saved->saved_engines[i];
> +		engine = idxd->engines[i];
> +
> +		engine->group = saved_engine->group;
> +
> +		kfree(saved_engine);
> +	}
> +	kfree(idxd_saved->saved_engines);
> +
> +	bitmap_copy(idxd->wq_enable_map, idxd_saved->saved_wq_enable_map,
> +		    idxd->max_wqs);
> +	bitmap_free(idxd_saved->saved_wq_enable_map);
> +
> +	for (i = 0; i < idxd->max_wqs; i++) {
> +		struct idxd_wq *saved_wq, *wq;
> +		size_t len;
> +
> +		if (!test_bit(i, idxd->wq_enable_map))
> +			continue;
> +
> +		saved_wq = idxd_saved->saved_wqs[i];
> +		wq = idxd->wqs[i];
> +
> +		mutex_lock(&wq->wq_lock);
> +
> +		wq->group = saved_wq->group;
> +		wq->flags = saved_wq->flags;
> +		wq->threshold = saved_wq->threshold;
> +		wq->size = saved_wq->size;
> +		wq->priority = saved_wq->priority;
> +		wq->type = saved_wq->type;
> +		len = strlen(saved_wq->name) + 1;
> +		strscpy(wq->name, saved_wq->name, len);
> +		wq->max_xfer_bytes = saved_wq->max_xfer_bytes;
> +		wq->max_batch_size = saved_wq->max_batch_size;
> +		wq->enqcmds_retries = saved_wq->enqcmds_retries;
> +		wq->descs = saved_wq->descs;
> +		wq->idxd_chan = saved_wq->idxd_chan;
> +		len = strlen(saved_wq->driver_name) + 1;
> +		strscpy(wq->driver_name, saved_wq->driver_name, len);
> +
> +		mutex_unlock(&wq->wq_lock);
> +
> +		kfree(saved_wq);
> +	}
> +
> +	kfree(idxd_saved->saved_wqs);
> +}
> +
>  /*
>   * Probe idxd PCI device.
>   * If idxd is not given, need to allocate idxd and set up its data.