[dpdk-stable] [PATCH 19.11] net/ena/base: fix testing for supported hash function

[Michal Krawczyk <mk@semihalf.com>]

[ upstream commit 6e585db68903b9ef8e0a547efc8f3e71af424397 ]

There was a bug in ena_com_fill_hash_function(), which was causing bit to
be shifted left one bit too much.

To fix that, the ENA_FFS macro is being used (returning the location of
the first bit set), hash_function value is being subtracted by 1 if any
hash function is supported by the device and BIT macro is used for
shifting for better verbosity.

Fixes: 99ecfbf845b3 ("ena: import communication layer")

Signed-off-by: Michal Krawczyk <mk@semihalf.com>
---
 drivers/net/ena/base/ena_com.c       | 22 +++++++++++++++-------
 drivers/net/ena/base/ena_plat_dpdk.h |  2 ++
 2 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ena/base/ena_com.c b/drivers/net/ena/base/ena_com.c
index b3cdf712e1..147c039124 100644
--- a/drivers/net/ena/base/ena_com.c
+++ b/drivers/net/ena/base/ena_com.c
@@ -2313,7 +2313,7 @@ int ena_com_set_hash_function(struct ena_com_dev *ena_dev)
 	if (unlikely(ret))
 		return ret;
 
-	if (get_resp.u.flow_hash_func.supported_func & (1 << rss->hash_func)) {
+	if (get_resp.u.flow_hash_func.supported_func & BIT(rss->hash_func)) {
 		ena_trc_err("Func hash %d isn't supported by device, abort\n",
 			    rss->hash_func);
 		return ENA_COM_UNSUPPORTED;
@@ -2356,12 +2356,14 @@ int ena_com_fill_hash_function(struct ena_com_dev *ena_dev,
 			       enum ena_admin_hash_functions func,
 			       const u8 *key, u16 key_len, u32 init_val)
 {
-	struct ena_rss *rss = &ena_dev->rss;
+	struct ena_admin_feature_rss_flow_hash_control *hash_key;
 	struct ena_admin_get_feat_resp get_resp;
-	struct ena_admin_feature_rss_flow_hash_control *hash_key =
-		rss->hash_key;
+	enum ena_admin_hash_functions old_func;
+	struct ena_rss *rss = &ena_dev->rss;
 	int rc;
 
+	hash_key = rss->hash_key;
+
 	/* Make sure size is a mult of DWs */
 	if (unlikely(key_len & 0x3))
 		return ENA_COM_INVAL;
@@ -2373,7 +2375,7 @@ int ena_com_fill_hash_function(struct ena_com_dev *ena_dev,
 	if (unlikely(rc))
 		return rc;
 
-	if (!((1 << func) & get_resp.u.flow_hash_func.supported_func)) {
+	if (!(BIT(func) & get_resp.u.flow_hash_func.supported_func)) {
 		ena_trc_err("Flow hash function %d isn't supported\n", func);
 		return ENA_COM_UNSUPPORTED;
 	}
@@ -2398,11 +2400,13 @@ int ena_com_fill_hash_function(struct ena_com_dev *ena_dev,
 		return ENA_COM_INVAL;
 	}
 
+	old_func = rss->hash_func;
+	rss->hash_func = func;
 	rc = ena_com_set_hash_function(ena_dev);
 
 	/* Restore the old function */
 	if (unlikely(rc))
-		ena_com_get_hash_function(ena_dev, NULL, NULL);
+		rss->hash_func = old_func;
 
 	return rc;
 }
@@ -2424,7 +2428,11 @@ int ena_com_get_hash_function(struct ena_com_dev *ena_dev,
 	if (unlikely(rc))
 		return rc;
 
-	rss->hash_func = get_resp.u.flow_hash_func.selected_func;
+	/* ENA_FFS returns 1 in case the lsb is set */
+	rss->hash_func = ENA_FFS(get_resp.u.flow_hash_func.selected_func);
+	if (rss->hash_func)
+		rss->hash_func--;
+
 	if (func)
 		*func = rss->hash_func;
 
diff --git a/drivers/net/ena/base/ena_plat_dpdk.h b/drivers/net/ena/base/ena_plat_dpdk.h
index dddfe65403..da97efca46 100644
--- a/drivers/net/ena/base/ena_plat_dpdk.h
+++ b/drivers/net/ena/base/ena_plat_dpdk.h
@@ -297,4 +297,6 @@ extern rte_atomic32_t ena_alloc_cnt;
 
 #define DIV_ROUND_UP(n, d) (((n) + (d) - 1) / (d))
 
+#define ENA_FFS(x) ffs(x)
+
 #endif /* DPDK_ENA_COM_ENA_PLAT_DPDK_H_ */
-- 
2.20.1