Re: [PATCH 1/2] Revert "IB/fmr_pool: ib_fmr_pool_flush() should flush all dirty FMRs"

[Benny Halevy <bhalevy@panasas.com>]

Pete, the subject says "PATCH 1/2" but I didn't see any follow-up message
for PATCH 2/2. Just wondering :)

Benny

On Feb. 26, 2008, 10:27 -0800, Pete Wyckoff <pw@osc.edu> wrote:
> This reverts commit a3cd7d9070be417a21905c997ee32d756d999b38.
> 
> The original commit breaks iSER reliably, making it complain:
> 
>     iser: iser_reg_page_vec:ib_fmr_pool_map_phys failed: -11
> 
> The FMR cleanup thread runs ib_fmr_batch_release() as dirty
> entries build up.  This commit causes clean but used FMR
> entries also to be purged.  During that process, another thread
> can see that there are no free FMRs and fail, even though
> there should always have been enough available.
> 
> Signed-off-by: Pete Wyckoff <pw@osc.edu>
> ---
>  drivers/infiniband/core/fmr_pool.c |   21 ++++++---------------
>  1 files changed, 6 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/infiniband/core/fmr_pool.c b/drivers/infiniband/core/fmr_pool.c
> index 7f00347..4044fdf 100644
> --- a/drivers/infiniband/core/fmr_pool.c
> +++ b/drivers/infiniband/core/fmr_pool.c
> @@ -139,7 +139,7 @@ static inline struct ib_pool_fmr *ib_fmr_cache_lookup(struct ib_fmr_pool *pool,
>  static void ib_fmr_batch_release(struct ib_fmr_pool *pool)
>  {
>  	int                 ret;
> -	struct ib_pool_fmr *fmr, *next;
> +	struct ib_pool_fmr *fmr;
>  	LIST_HEAD(unmap_list);
>  	LIST_HEAD(fmr_list);
>  
> @@ -158,20 +158,6 @@ static void ib_fmr_batch_release(struct ib_fmr_pool *pool)
>  #endif
>  	}
>  
> -	/*
> -	 * The free_list may hold FMRs that have been put there
> -	 * because they haven't reached the max_remap count.
> -	 * Invalidate their mapping as well.
> -	 */
> -	list_for_each_entry_safe(fmr, next, &pool->free_list, list) {
> -		if (fmr->remap_count == 0)
> -			continue;
> -		hlist_del_init(&fmr->cache_node);
> -		fmr->remap_count = 0;
> -		list_add_tail(&fmr->fmr->list, &fmr_list);
> -		list_move(&fmr->list, &unmap_list);
> -	}
> -
>  	list_splice(&pool->dirty_list, &unmap_list);
>  	INIT_LIST_HEAD(&pool->dirty_list);
>  	pool->dirty_len = 0;
> @@ -384,6 +370,11 @@ void ib_destroy_fmr_pool(struct ib_fmr_pool *pool)
>  
>  	i = 0;
>  	list_for_each_entry_safe(fmr, tmp, &pool->free_list, list) {
> +		if (fmr->remap_count) {
> +			INIT_LIST_HEAD(&fmr_list);
> +			list_add_tail(&fmr->fmr->list, &fmr_list);
> +			ib_unmap_fmr(&fmr_list);
> +		}
>  		ib_dealloc_fmr(fmr->fmr);
>  		list_del(&fmr->list);
>  		kfree(fmr);