diff options
| author | stephen hemminger <stephen@networkplumber.org> | 2017-04-24 18:33:38 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-04-25 11:56:59 -0400 |
| commit | fdfb70d275223b9d69d5d3abe1f88507da579139 (patch) | |
| tree | 72bc1cd4a60af46c4250234ae2a968660eac8d3c /drivers | |
| parent | a23f6ce6d95900ca83b44b6fa691afe6c7d4b941 (diff) | |
| download | linux-fdfb70d275223b9d69d5d3abe1f88507da579139.tar.bz2 | |
netvsc: fix calculation of available send sections
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 <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/net/hyperv/hyperv_net.h | 1 | ||||
| -rw-r--r-- | 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; } |