Re: [Intel-gfx] [PATCH 02/16] drm/i915/vm_bind: Add __i915_sw_fence_await_reservation()

[Matthew Auld <matthew.auld@intel.com>]

On 28/09/2022 07:19, Niranjana Vishwanathapura wrote:
> Add function __i915_sw_fence_await_reservation() for
> asynchronous wait on a dma-resv object with specified
> dma_resv_usage. This is required for async vma unbind
> with vm_bind.
> 
> Signed-off-by: Niranjana Vishwanathapura <niranjana.vishwanathapura@intel.com>
> ---
>   drivers/gpu/drm/i915/i915_sw_fence.c | 28 +++++++++++++++++++++-------
>   drivers/gpu/drm/i915/i915_sw_fence.h | 23 +++++++++++++++++------
>   2 files changed, 38 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_sw_fence.c b/drivers/gpu/drm/i915/i915_sw_fence.c
> index cc2a8821d22a..b7a10c374a08 100644
> --- a/drivers/gpu/drm/i915/i915_sw_fence.c
> +++ b/drivers/gpu/drm/i915/i915_sw_fence.c
> @@ -7,7 +7,6 @@
>   #include <linux/slab.h>
>   #include <linux/dma-fence.h>
>   #include <linux/irq_work.h>
> -#include <linux/dma-resv.h>
>   
>   #include "i915_sw_fence.h"
>   #include "i915_selftest.h"
> @@ -569,11 +568,26 @@ int __i915_sw_fence_await_dma_fence(struct i915_sw_fence *fence,
>   	return ret;
>   }
>   
> -int i915_sw_fence_await_reservation(struct i915_sw_fence *fence,
> -				    struct dma_resv *resv,
> -				    bool write,
> -				    unsigned long timeout,
> -				    gfp_t gfp)
> +/**
> + * __i915_sw_fence_await_reservation() - Setup a fence to wait on a dma-resv
> + * object with specified usage.
> + * @fence: the fence that needs to wait
> + * @resv: dma-resv object
> + * @usage: dma_resv_usage (See enum dma_resv_usage)
> + * @timeout: how long to wait in jiffies
> + * @gfp: allocation mode
> + *
> + * Setup the @fence to asynchronously wait on dma-resv object @resv for usage
> + * @usage to complete before signaling.

s/usage @usage/@usage/ ?

> + *
> + * Returns 0 if there is nothing to wait on, -ve upon error and >0 upon

What does "-ve" mean btw?

Acked-by: Matthew Auld <matthew.auld@intel.com>

> + * successfully setting up the wait.
> + */
> +int __i915_sw_fence_await_reservation(struct i915_sw_fence *fence,
> +				      struct dma_resv *resv,
> +				      enum dma_resv_usage usage,
> +				      unsigned long timeout,
> +				      gfp_t gfp)
>   {
>   	struct dma_resv_iter cursor;
>   	struct dma_fence *f;
> @@ -582,7 +596,7 @@ int i915_sw_fence_await_reservation(struct i915_sw_fence *fence,
>   	debug_fence_assert(fence);
>   	might_sleep_if(gfpflags_allow_blocking(gfp));
>   
> -	dma_resv_iter_begin(&cursor, resv, dma_resv_usage_rw(write));
> +	dma_resv_iter_begin(&cursor, resv, usage);
>   	dma_resv_for_each_fence_unlocked(&cursor, f) {
>   		pending = i915_sw_fence_await_dma_fence(fence, f, timeout,
>   							gfp);
> diff --git a/drivers/gpu/drm/i915/i915_sw_fence.h b/drivers/gpu/drm/i915/i915_sw_fence.h
> index f752bfc7c6e1..9c4859dc4c0d 100644
> --- a/drivers/gpu/drm/i915/i915_sw_fence.h
> +++ b/drivers/gpu/drm/i915/i915_sw_fence.h
> @@ -10,13 +10,13 @@
>   #define _I915_SW_FENCE_H_
>   
>   #include <linux/dma-fence.h>
> +#include <linux/dma-resv.h>
>   #include <linux/gfp.h>
>   #include <linux/kref.h>
>   #include <linux/notifier.h> /* for NOTIFY_DONE */
>   #include <linux/wait.h>
>   
>   struct completion;
> -struct dma_resv;
>   struct i915_sw_fence;
>   
>   enum i915_sw_fence_notify {
> @@ -89,11 +89,22 @@ int i915_sw_fence_await_dma_fence(struct i915_sw_fence *fence,
>   				  unsigned long timeout,
>   				  gfp_t gfp);
>   
> -int i915_sw_fence_await_reservation(struct i915_sw_fence *fence,
> -				    struct dma_resv *resv,
> -				    bool write,
> -				    unsigned long timeout,
> -				    gfp_t gfp);
> +int __i915_sw_fence_await_reservation(struct i915_sw_fence *fence,
> +				      struct dma_resv *resv,
> +				      enum dma_resv_usage usage,
> +				      unsigned long timeout,
> +				      gfp_t gfp);
> +
> +static inline int i915_sw_fence_await_reservation(struct i915_sw_fence *fence,
> +						  struct dma_resv *resv,
> +						  bool write,
> +						  unsigned long timeout,
> +						  gfp_t gfp)
> +{
> +	return __i915_sw_fence_await_reservation(fence, resv,
> +						 dma_resv_usage_rw(write),
> +						 timeout, gfp);
> +}
>   
>   bool i915_sw_fence_await(struct i915_sw_fence *fence);
>   void i915_sw_fence_complete(struct i915_sw_fence *fence);