From a656eb758fc6e6a42659ecf5ba34a5c5a2aeec17 Mon Sep 17 00:00:00 2001 From: Olaf Kirch Date: Wed, 16 Jan 2008 18:36:27 +0100 Subject: [PATCH] IB/fmr_pool: Flush serial numbers can get out of sync Normally, the serial numbers for flush requests and flushes executed for an FMR pool should be in sync. However, if the FMR pool flushes dirty FMRs because the dirty_watermark was reached, we wake up the cleanup thread and let it do its stuff. As a side effect, the cleanup thread increments pool->flush_ser, which leaves it one higher than pool->req_ser. The next time the user calls ib_flush_fmr_pool(), the cleanup thread will be woken up, but ib_flush_fmr_pool() won't wait for the flush to complete because flush_ser is already past req_ser. This means the FMRs that the user expects to be flushed may not have all been flushed when the function returns. Fix this by telling the cleanup thread to do work exclusively by incrementing req_ser, and by moving the comparison of dirty_len and dirty_watermark into ib_fmr_pool_unmap(). Signed-off-by: Olaf Kirch --- drivers/infiniband/core/fmr_pool.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/drivers/infiniband/core/fmr_pool.c b/drivers/infiniband/core/fmr_pool.c index e8d5f6b64998..4a476a870214 100644 --- a/drivers/infiniband/core/fmr_pool.c +++ b/drivers/infiniband/core/fmr_pool.c @@ -182,8 +182,7 @@ static int ib_fmr_cleanup_thread(void *pool_ptr) struct ib_fmr_pool *pool = pool_ptr; do { - if (pool->dirty_len >= pool->dirty_watermark || - atomic_read(&pool->flush_ser) - atomic_read(&pool->req_ser) < 0) { + if (atomic_read(&pool->flush_ser) - atomic_read(&pool->req_ser) < 0) { ib_fmr_batch_release(pool); atomic_inc(&pool->flush_ser); @@ -194,8 +193,7 @@ static int ib_fmr_cleanup_thread(void *pool_ptr) } set_current_state(TASK_INTERRUPTIBLE); - if (pool->dirty_len < pool->dirty_watermark && - atomic_read(&pool->flush_ser) - atomic_read(&pool->req_ser) >= 0 && + if (atomic_read(&pool->flush_ser) - atomic_read(&pool->req_ser) >= 0 && !kthread_should_stop()) schedule(); __set_current_state(TASK_RUNNING); @@ -511,8 +509,10 @@ int ib_fmr_pool_unmap(struct ib_pool_fmr *fmr) list_add_tail(&fmr->list, &pool->free_list); } else { list_add_tail(&fmr->list, &pool->dirty_list); - ++pool->dirty_len; - wake_up_process(pool->thread); + if (++pool->dirty_len >= pool->dirty_watermark) { + atomic_inc(&pool->req_ser); + wake_up_process(pool->thread); + } } }