My change (introduced in 4.11) to use find_first_clear_bit
incorrectly assumed that the size argument was words, not bits.
The effect was only a small limited number of the available send
sections were being actually used. This can cause performance loss
with some workloads.
Since map_words is now used only during initialization, it can
be on stack instead of in per-device data.
Fixes: b58a185801da ("netvsc: simplify get next send section")
Signed-off-by: Stephen Hemminger <sthem...@microsoft.com>
---
drivers/net/hyperv/hyperv_net.h | 1 -
drivers/net/hyperv/netvsc.c | 9 ++++-----
2 files changed, 4 insertions(+), 6 deletions(-)
diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
index f9f3dba7a588..db23cb36ae5c 100644
--- a/drivers/net/hyperv/hyperv_net.h
+++ b/drivers/net/hyperv/hyperv_net.h
@@ -751,7 +751,6 @@ struct netvsc_device {
u32 send_section_cnt;
u32 send_section_size;
unsigned long *send_section_map;
- int map_words;
/* Used for NetVSP initialization protocol */
struct completion channel_init_wait;
diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index 8dd0b8770328..15ef713d96c0 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -236,6 +236,7 @@ static int netvsc_init_buf(struct hv_device *device)
struct netvsc_device *net_device;
struct nvsp_message *init_packet;
struct net_device *ndev;
+ size_t map_words;
int node;
net_device = get_outbound_net_device(device);
@@ -401,11 +402,9 @@ static int netvsc_init_buf(struct hv_device *device)
net_device->send_section_size, net_device->send_section_cnt);
/* Setup state for managing the send buffer. */
- net_device->map_words = DIV_ROUND_UP(net_device->send_section_cnt,
- BITS_PER_LONG);
+ map_words = DIV_ROUND_UP(net_device->send_section_cnt, BITS_PER_LONG);
- net_device->send_section_map = kcalloc(net_device->map_words,
- sizeof(ulong), GFP_KERNEL);
+ net_device->send_section_map = kcalloc(map_words, sizeof(ulong),
GFP_KERNEL);
if (net_device->send_section_map == NULL) {
ret = -ENOMEM;
goto cleanup;
@@ -683,7 +682,7 @@ static u32 netvsc_get_next_send_section(struct
netvsc_device *net_device)
unsigned long *map_addr = net_device->send_section_map;
unsigned int i;
- for_each_clear_bit(i, map_addr, net_device->map_words) {
+ for_each_clear_bit(i, map_addr, net_device->send_section_cnt) {
if (sync_test_and_set_bit(i, map_addr) == 0)
return i;
}
--
2.11.0
