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From: Bruce Richardson <bruce.richardson@intel.com>
To: dev@dpdk.org
Cc: Bruce Richardson <bruce.richardson@intel.com>,
	kevin.laatz@intel.com, stable@dpdk.org,
	Jiayu Hu <jiayu.hu@intel.com>,
	Conor Walsh <conor.walsh@intel.com>,
	Chengwen Feng <fengchengwen@huawei.com>
Subject: [PATCH v2 1/4] dma/idxd: fix burst capacity calculation
Date: Tue, 11 Jan 2022 13:41:02 +0000	[thread overview]
Message-ID: <20220111134105.1007191-2-bruce.richardson@intel.com> (raw)
In-Reply-To: <20220111134105.1007191-1-bruce.richardson@intel.com>

When the maximum burst size supported by HW is less than the available
ring space, incorrect capacity was returned when there was already some
jobs queued up for submission. This was because the capacity calculation
failed to subtract the number of already-enqueued jobs from the max
burst size. After subtraction is done, ensure that any negative values
(which should never occur if the user respects the reported limits), are
clamped to zero.

Fixes: 9459de4edc99 ("dma/idxd: add burst capacity")
Cc: kevin.laatz@intel.com
Cc: stable@dpdk.org

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: Kevin Laatz <kevin.laatz@intel.com>
Tested-by: Jiayu Hu <jiayu.hu@intel.com>
---
 drivers/dma/idxd/idxd_common.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/dma/idxd/idxd_common.c b/drivers/dma/idxd/idxd_common.c
index fc11b11337..4442d1cbbd 100644
--- a/drivers/dma/idxd/idxd_common.c
+++ b/drivers/dma/idxd/idxd_common.c
@@ -485,7 +485,9 @@ idxd_burst_capacity(const void *dev_private, uint16_t vchan __rte_unused)
 		write_idx += idxd->desc_ring_mask + 1;
 	used_space = write_idx - idxd->ids_returned;
 
-	return RTE_MIN((idxd->desc_ring_mask - used_space), idxd->max_batch_size);
+	const int ret = RTE_MIN((idxd->desc_ring_mask - used_space),
+			(idxd->max_batch_size - idxd->batch_size));
+	return ret < 0 ? 0 : (uint16_t)ret;
 }
 
 int
-- 
2.32.0


  reply	other threads:[~2022-01-11 13:41 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-20 17:05 [PATCH] " Bruce Richardson
2022-01-04 17:16 ` Kevin Laatz
2022-01-05  1:32   ` Hu, Jiayu
2022-01-10 13:09 ` Pai G, Sunil
2022-01-10 13:25   ` Bruce Richardson
2022-01-10 13:44     ` Pai G, Sunil
2022-01-10 16:18       ` Bruce Richardson
2022-01-11 13:41 ` [PATCH v2 0/4] fixes for dma/idxd Bruce Richardson
2022-01-11 13:41   ` Bruce Richardson [this message]
2022-01-11 13:41   ` [PATCH v2 2/4] dma/idxd: fix paths to driver sysfs directory Bruce Richardson
2022-01-11 16:50     ` Kevin Laatz
2022-01-11 13:41   ` [PATCH v2 3/4] dma/idxd: fix wrap-around in burst capacity calculation Bruce Richardson
2022-01-11 13:45     ` Pai G, Sunil
2022-01-11 16:50     ` Kevin Laatz
2022-01-11 13:41   ` [PATCH v2 4/4] test_dmadev: increase iterations of capacity test case Bruce Richardson
2022-01-11 16:50     ` Kevin Laatz
2022-01-20 13:06   ` [PATCH v2 0/4] fixes for dma/idxd Thomas Monjalon

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