Re: [PATCH v2] drm/xe/pf: Fix EAGAIN sign in pf_migration_consume()

[Gustavo Sousa <gustavo.sousa@intel.com>]

Shuicheng Lin <shuicheng.lin@intel.com> writes:

> PTR_ERR() returns a negative value, so comparing against the positive
> EAGAIN is always true for ERR_PTR(-EAGAIN), causing pf_migration_consume()
> to bail out instead of continuing to the remaining GTs. On multi-GT
> platforms this can skip GTs that already have data ready.
>
> Compare against -EAGAIN to match the intent (and the following line
> that correctly uses -EAGAIN). While at it, gate PTR_ERR() with
> IS_ERR().
>
> v2: add IS_ERR() guard before PTR_ERR(). (Gustavo)
>
> Fixes: 67df4a5cbc58 ("drm/xe/pf: Add data structures and handlers for migration rings")
> Cc: Gustavo Sousa <gustavo.sousa@intel.com>
> Cc: Michał Winiarski <michal.winiarski@intel.com>
> Signed-off-by: Shuicheng Lin <shuicheng.lin@intel.com>

Reviewed-by: Gustavo Sousa <gustavo.sousa@intel.com>

> ---
>  drivers/gpu/drm/xe/xe_sriov_pf_migration.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/xe/xe_sriov_pf_migration.c b/drivers/gpu/drm/xe/xe_sriov_pf_migration.c
> index 6c4b16409cc9..150a241110fb 100644
> --- a/drivers/gpu/drm/xe/xe_sriov_pf_migration.c
> +++ b/drivers/gpu/drm/xe/xe_sriov_pf_migration.c
> @@ -149,10 +149,11 @@ pf_migration_consume(struct xe_device *xe, unsigned int vfid)
>  
>  	for_each_gt(gt, xe, gt_id) {
>  		data = xe_gt_sriov_pf_migration_save_consume(gt, vfid);
> -		if (data && PTR_ERR(data) != EAGAIN)
> +		if (!data)
> +			continue;
> +		if (!IS_ERR(data) || PTR_ERR(data) != -EAGAIN)
>  			return data;
> -		if (PTR_ERR(data) == -EAGAIN)
> -			more_data = true;
> +		more_data = true;
>  	}
>  
>  	if (!more_data)
> -- 
> 2.43.0