From dbc9ae665b5c8d18e2b38ab9059ba7dfc4088dc4 Mon Sep 17 00:00:00 2001 From: Bruce Richardson Date: Wed, 12 May 2021 14:49:59 +0000 Subject: [PATCH] raw/ioat: fix ring space checks When enqueuing a descriptor, when checking that there is at least one slot free for the current descriptor and a later batch descriptor, we need to test for both two free and one free, in case the last write was a batch descriptor which is allowed to use the "spare" slot. Similarly, when computing the free space in the ring to return to the user, we need to take account of the same condition, so that we do not return a "-1" ring space value, by blindly subtracting "2". Fixes: 245efe544d8e ("raw/ioat: report status of completed jobs") Reported-by: Jiayu Hu Signed-off-by: Bruce Richardson Acked-by: Kevin Laatz --- drivers/raw/ioat/rte_idxd_rawdev_fns.h | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/raw/ioat/rte_idxd_rawdev_fns.h b/drivers/raw/ioat/rte_idxd_rawdev_fns.h index dbd8dfc507..0eea5368de 100644 --- a/drivers/raw/ioat/rte_idxd_rawdev_fns.h +++ b/drivers/raw/ioat/rte_idxd_rawdev_fns.h @@ -132,7 +132,7 @@ __idxd_burst_capacity(int dev_id) struct rte_idxd_rawdev *idxd = (struct rte_idxd_rawdev *)rte_rawdevs[dev_id].dev_private; uint16_t write_idx = idxd->batch_start + idxd->batch_size; - uint16_t used_space; + uint16_t used_space, free_space; /* Check for space in the batch ring */ if ((idxd->batch_idx_read == 0 && idxd->batch_idx_write == idxd->max_batches) || @@ -147,7 +147,10 @@ __idxd_burst_capacity(int dev_id) /* Return amount of free space in the descriptor ring * subtract 1 for space for batch descriptor and 1 for possible null desc */ - return idxd->desc_ring_mask - used_space - 2; + free_space = idxd->desc_ring_mask - used_space; + if (free_space < 2) + return 0; + return free_space - 2; } static __rte_always_inline rte_iova_t @@ -174,7 +177,8 @@ __idxd_write_desc(int dev_id, idxd->batch_idx_write + 1 == idxd->batch_idx_read) goto failed; /* for descriptor ring, we always need a slot for batch completion */ - if (((write_idx + 2) & mask) == idxd->hdls_read) + if (((write_idx + 2) & mask) == idxd->hdls_read || + ((write_idx + 1) & mask) == idxd->hdls_read) goto failed; /* write desc and handle. Note, descriptors don't wrap */ -- 2.20.1