[PATCH v4 07/31] net/ena/base: limit exponential backoff exp

[shaibran at amazon.com]

From: Shai Brandes <shaibran at amazon.com>

Limit the value of the exponent used for this backoff
at (1<<16) to prevent it from reaching to an excessive
value (1<<32) or potentially even overflowing.
In addition, for uniformity and readability purposes,
the min/max parameter in the calls of ENA_MIN32 and
ENA_MAX32 macros was changed to be first.

Signed-off-by: Shai Brandes <shaibran at amazon.com>
Reviewed-by: Amit Bernstein <amitbern at amazon.com>
---
 drivers/net/ena/base/ena_com.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ena/base/ena_com.c b/drivers/net/ena/base/ena_com.c
index 6953a1fa33..31c37b0ab3 100644
--- a/drivers/net/ena/base/ena_com.c
+++ b/drivers/net/ena/base/ena_com.c
@@ -34,6 +34,8 @@
 
 #define ENA_REGS_ADMIN_INTR_MASK 1
 
+#define ENA_MAX_BACKOFF_DELAY_EXP 16U
+
 #define ENA_MIN_ADMIN_POLL_US 100
 
 #define ENA_MAX_ADMIN_POLL_US 5000
@@ -545,8 +547,9 @@ static int ena_com_comp_status_to_errno(struct ena_com_admin_queue *admin_queue,
 
 static void ena_delay_exponential_backoff_us(u32 exp, u32 delay_us)
 {
+	exp = ENA_MIN32(ENA_MAX_BACKOFF_DELAY_EXP, exp);
 	delay_us = ENA_MAX32(ENA_MIN_ADMIN_POLL_US, delay_us);
-	delay_us = ENA_MIN32(delay_us * (1U << exp), ENA_MAX_ADMIN_POLL_US);
+	delay_us = ENA_MIN32(ENA_MAX_ADMIN_POLL_US, delay_us * (1U << exp));
 	ENA_USLEEP(delay_us);
 }
 
-- 
2.17.1