Re: [PATCH net-next 6/6] net: qualcomm: rmnet: don't use C bit-fields in rmnet checksum header
On 3/4/21 11:26 PM, Bjorn Andersson wrote:
On Thu 04 Mar 16:34 CST 2021, Alex Elder wrote:
Replace the use of C bit-fields in the rmnet_map_ul_csum_header
structure with a single two-byte (big endian) structure member,
and use field masks to encode or get values within it.
Previously rmnet_map_ipv4_ul_csum_header() would update values in
the host byte-order fields, and then forcibly fix their byte order
using a combination of byte order operations and types.
Instead, just compute the value that needs to go into the new
structure member and save it with a simple byte-order conversion.
Make similar simplifications in rmnet_map_ipv6_ul_csum_header().
Finally, in rmnet_map_checksum_uplink_packet() a set of assignments
zeroes every field in the upload checksum header. Replace that with
a single memset() operation.
Signed-off-by: Alex Elder
---
.../ethernet/qualcomm/rmnet/rmnet_map_data.c | 34 ++-
include/linux/if_rmnet.h | 21 ++--
2 files changed, 21 insertions(+), 34 deletions(-)
diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
index 29d485b868a65..db76bbf000aa1 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
@@ -198,23 +198,19 @@ rmnet_map_ipv4_ul_csum_header(void *iphdr,
struct rmnet_map_ul_csum_header *ul_header,
struct sk_buff *skb)
{
- __be16 *hdr = (__be16 *)ul_header;
struct iphdr *ip4h = iphdr;
u16 offset;
+ u16 val;
offset = skb_transport_header(skb) - (unsigned char *)iphdr;
ul_header->csum_start_offset = htons(offset);
- ul_header->csum_insert_offset = skb->csum_offset;
- ul_header->csum_enabled = 1;
+ val = be16_encode_bits(1, MAP_CSUM_UL_ENABLED_FMASK);
Why are you using be16_ here? Won't that cancel the htons() below?
Yes. This was a mistake, and as you know, the kernel test
robot caught the problem with assigning a big endian value
to a host byte order variable. This cannot have worked
before and I'm not sure what happened.
I've updated this series and am re-testing everything. That
includes running the patches through sparse, but also includes
running with checksum offload enabled and verifying errors
are not reported when checksum offload active.
-Alex
Regards,
Bjorn
if (ip4h->protocol == IPPROTO_UDP)
- ul_header->udp_ind = 1;
- else
- ul_header->udp_ind = 0;
+ val |= be16_encode_bits(1, MAP_CSUM_UL_UDP_FMASK);
+ val |= be16_encode_bits(skb->csum_offset, MAP_CSUM_UL_OFFSET_FMASK);
- /* Changing remaining fields to network order */
- hdr++;
- *hdr = htons((__force u16)*hdr);
+ ul_header->csum_info = htons(val);
skb->ip_summed = CHECKSUM_NONE;
@@ -241,24 +237,19 @@ rmnet_map_ipv6_ul_csum_header(void *ip6hdr,
struct rmnet_map_ul_csum_header *ul_header,
struct sk_buff *skb)
{
- __be16 *hdr = (__be16 *)ul_header;
struct ipv6hdr *ip6h = ip6hdr;
u16 offset;
+ u16 val;
offset = skb_transport_header(skb) - (unsigned char *)ip6hdr;
ul_header->csum_start_offset = htons(offset);
- ul_header->csum_insert_offset = skb->csum_offset;
- ul_header->csum_enabled = 1;
-
+ val = be16_encode_bits(1, MAP_CSUM_UL_ENABLED_FMASK);
if (ip6h->nexthdr == IPPROTO_UDP)
- ul_header->udp_ind = 1;
- else
- ul_header->udp_ind = 0;
+ val |= be16_encode_bits(1, MAP_CSUM_UL_UDP_FMASK);
+ val |= be16_encode_bits(skb->csum_offset, MAP_CSUM_UL_OFFSET_FMASK);
- /* Changing remaining fields to network order */
- hdr++;
- *hdr = htons((__force u16)*hdr);
+ ul_header->csum_info = htons(val);
skb->ip_summed = CHECKSUM_NONE;
@@ -425,10 +416,7 @@ void rmnet_map_checksum_uplink_packet(struct sk_buff *skb,
}
sw_csum:
- ul_header->csum_start_offset = 0;
- ul_header->csum_insert_offset = 0;
- ul_header->csum_enabled = 0;
- ul_header->udp_ind = 0;
+ memset(ul_header, 0, sizeof(*ul_header));
priv->stats.csum_sw++;
}
diff --git a/include/linux/if_rmnet.h b/include/linux/if_rmnet.h
index 1fbb7531238b6..149d696feb520 100644
--- a/include/linux/if_rmnet.h
+++ b/include/linux/if_rmnet.h
@@ -33,17 +33,16 @@ struct rmnet_map_dl_csum_trailer {
struct rmnet_map_ul_csum_header {
__be16 csum_start_offset;
-#if defined(__LITTLE_ENDIAN_BITFIELD)
- u16 csum_insert_offset:14;
- u16 udp_ind:1;
- u16 csum_enabled:1;
-#elif defined (__BIG_ENDIAN_BITFIELD)
- u16 csum_enabled:1;
- u16 udp_ind:1;
- u16 csum_insert_offset:14;
-#else
-#error "Please fix "
-#endif
+ __be16
Re: [PATCH net-next 6/6] net: qualcomm: rmnet: don't use C bit-fields in rmnet checksum header
On Thu 04 Mar 16:34 CST 2021, Alex Elder wrote:
> Replace the use of C bit-fields in the rmnet_map_ul_csum_header
> structure with a single two-byte (big endian) structure member,
> and use field masks to encode or get values within it.
>
> Previously rmnet_map_ipv4_ul_csum_header() would update values in
> the host byte-order fields, and then forcibly fix their byte order
> using a combination of byte order operations and types.
>
> Instead, just compute the value that needs to go into the new
> structure member and save it with a simple byte-order conversion.
>
> Make similar simplifications in rmnet_map_ipv6_ul_csum_header().
>
> Finally, in rmnet_map_checksum_uplink_packet() a set of assignments
> zeroes every field in the upload checksum header. Replace that with
> a single memset() operation.
>
> Signed-off-by: Alex Elder
> ---
> .../ethernet/qualcomm/rmnet/rmnet_map_data.c | 34 ++-
> include/linux/if_rmnet.h | 21 ++--
> 2 files changed, 21 insertions(+), 34 deletions(-)
>
> diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
> b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
> index 29d485b868a65..db76bbf000aa1 100644
> --- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
> +++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
> @@ -198,23 +198,19 @@ rmnet_map_ipv4_ul_csum_header(void *iphdr,
> struct rmnet_map_ul_csum_header *ul_header,
> struct sk_buff *skb)
> {
> - __be16 *hdr = (__be16 *)ul_header;
> struct iphdr *ip4h = iphdr;
> u16 offset;
> + u16 val;
>
> offset = skb_transport_header(skb) - (unsigned char *)iphdr;
> ul_header->csum_start_offset = htons(offset);
>
> - ul_header->csum_insert_offset = skb->csum_offset;
> - ul_header->csum_enabled = 1;
> + val = be16_encode_bits(1, MAP_CSUM_UL_ENABLED_FMASK);
Why are you using be16_ here? Won't that cancel the htons() below?
Regards,
Bjorn
> if (ip4h->protocol == IPPROTO_UDP)
> - ul_header->udp_ind = 1;
> - else
> - ul_header->udp_ind = 0;
> + val |= be16_encode_bits(1, MAP_CSUM_UL_UDP_FMASK);
> + val |= be16_encode_bits(skb->csum_offset, MAP_CSUM_UL_OFFSET_FMASK);
>
> - /* Changing remaining fields to network order */
> - hdr++;
> - *hdr = htons((__force u16)*hdr);
> + ul_header->csum_info = htons(val);
>
> skb->ip_summed = CHECKSUM_NONE;
>
> @@ -241,24 +237,19 @@ rmnet_map_ipv6_ul_csum_header(void *ip6hdr,
> struct rmnet_map_ul_csum_header *ul_header,
> struct sk_buff *skb)
> {
> - __be16 *hdr = (__be16 *)ul_header;
> struct ipv6hdr *ip6h = ip6hdr;
> u16 offset;
> + u16 val;
>
> offset = skb_transport_header(skb) - (unsigned char *)ip6hdr;
> ul_header->csum_start_offset = htons(offset);
>
> - ul_header->csum_insert_offset = skb->csum_offset;
> - ul_header->csum_enabled = 1;
> -
> + val = be16_encode_bits(1, MAP_CSUM_UL_ENABLED_FMASK);
> if (ip6h->nexthdr == IPPROTO_UDP)
> - ul_header->udp_ind = 1;
> - else
> - ul_header->udp_ind = 0;
> + val |= be16_encode_bits(1, MAP_CSUM_UL_UDP_FMASK);
> + val |= be16_encode_bits(skb->csum_offset, MAP_CSUM_UL_OFFSET_FMASK);
>
> - /* Changing remaining fields to network order */
> - hdr++;
> - *hdr = htons((__force u16)*hdr);
> + ul_header->csum_info = htons(val);
>
> skb->ip_summed = CHECKSUM_NONE;
>
> @@ -425,10 +416,7 @@ void rmnet_map_checksum_uplink_packet(struct sk_buff
> *skb,
> }
>
> sw_csum:
> - ul_header->csum_start_offset = 0;
> - ul_header->csum_insert_offset = 0;
> - ul_header->csum_enabled = 0;
> - ul_header->udp_ind = 0;
> + memset(ul_header, 0, sizeof(*ul_header));
>
> priv->stats.csum_sw++;
> }
> diff --git a/include/linux/if_rmnet.h b/include/linux/if_rmnet.h
> index 1fbb7531238b6..149d696feb520 100644
> --- a/include/linux/if_rmnet.h
> +++ b/include/linux/if_rmnet.h
> @@ -33,17 +33,16 @@ struct rmnet_map_dl_csum_trailer {
>
> struct rmnet_map_ul_csum_header {
> __be16 csum_start_offset;
> -#if defined(__LITTLE_ENDIAN_BITFIELD)
> - u16 csum_insert_offset:14;
> - u16 udp_ind:1;
> - u16 csum_enabled:1;
> -#elif defined (__BIG_ENDIAN_BITFIELD)
> - u16 csum_enabled:1;
> - u16 udp_ind:1;
> - u16 csum_insert_offset:14;
> -#else
> -#error "Please fix "
> -#endif
> + __be16 csum_info; /* MAP_CSUM_UL_*_FMASK */
> } __aligned(1);
>
> +/* csum_info field:
> + * ENABLED: 1 = checksum computation requested
> + * UDP: 1 = UDP checksum (zero checkum means no checksum)
> + * OFFSET: where (offset in bytes) to insert computed checksum
> + */
> +#define MAP_CSUM_UL_OFFSET_FMASK GENMASK(13, 0)
> +#define MAP_CSUM_UL_UDP_FMASK
[PATCH net-next 6/6] net: qualcomm: rmnet: don't use C bit-fields in rmnet checksum header
Replace the use of C bit-fields in the rmnet_map_ul_csum_header
structure with a single two-byte (big endian) structure member,
and use field masks to encode or get values within it.
Previously rmnet_map_ipv4_ul_csum_header() would update values in
the host byte-order fields, and then forcibly fix their byte order
using a combination of byte order operations and types.
Instead, just compute the value that needs to go into the new
structure member and save it with a simple byte-order conversion.
Make similar simplifications in rmnet_map_ipv6_ul_csum_header().
Finally, in rmnet_map_checksum_uplink_packet() a set of assignments
zeroes every field in the upload checksum header. Replace that with
a single memset() operation.
Signed-off-by: Alex Elder
---
.../ethernet/qualcomm/rmnet/rmnet_map_data.c | 34 ++-
include/linux/if_rmnet.h | 21 ++--
2 files changed, 21 insertions(+), 34 deletions(-)
diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
index 29d485b868a65..db76bbf000aa1 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
@@ -198,23 +198,19 @@ rmnet_map_ipv4_ul_csum_header(void *iphdr,
struct rmnet_map_ul_csum_header *ul_header,
struct sk_buff *skb)
{
- __be16 *hdr = (__be16 *)ul_header;
struct iphdr *ip4h = iphdr;
u16 offset;
+ u16 val;
offset = skb_transport_header(skb) - (unsigned char *)iphdr;
ul_header->csum_start_offset = htons(offset);
- ul_header->csum_insert_offset = skb->csum_offset;
- ul_header->csum_enabled = 1;
+ val = be16_encode_bits(1, MAP_CSUM_UL_ENABLED_FMASK);
if (ip4h->protocol == IPPROTO_UDP)
- ul_header->udp_ind = 1;
- else
- ul_header->udp_ind = 0;
+ val |= be16_encode_bits(1, MAP_CSUM_UL_UDP_FMASK);
+ val |= be16_encode_bits(skb->csum_offset, MAP_CSUM_UL_OFFSET_FMASK);
- /* Changing remaining fields to network order */
- hdr++;
- *hdr = htons((__force u16)*hdr);
+ ul_header->csum_info = htons(val);
skb->ip_summed = CHECKSUM_NONE;
@@ -241,24 +237,19 @@ rmnet_map_ipv6_ul_csum_header(void *ip6hdr,
struct rmnet_map_ul_csum_header *ul_header,
struct sk_buff *skb)
{
- __be16 *hdr = (__be16 *)ul_header;
struct ipv6hdr *ip6h = ip6hdr;
u16 offset;
+ u16 val;
offset = skb_transport_header(skb) - (unsigned char *)ip6hdr;
ul_header->csum_start_offset = htons(offset);
- ul_header->csum_insert_offset = skb->csum_offset;
- ul_header->csum_enabled = 1;
-
+ val = be16_encode_bits(1, MAP_CSUM_UL_ENABLED_FMASK);
if (ip6h->nexthdr == IPPROTO_UDP)
- ul_header->udp_ind = 1;
- else
- ul_header->udp_ind = 0;
+ val |= be16_encode_bits(1, MAP_CSUM_UL_UDP_FMASK);
+ val |= be16_encode_bits(skb->csum_offset, MAP_CSUM_UL_OFFSET_FMASK);
- /* Changing remaining fields to network order */
- hdr++;
- *hdr = htons((__force u16)*hdr);
+ ul_header->csum_info = htons(val);
skb->ip_summed = CHECKSUM_NONE;
@@ -425,10 +416,7 @@ void rmnet_map_checksum_uplink_packet(struct sk_buff *skb,
}
sw_csum:
- ul_header->csum_start_offset = 0;
- ul_header->csum_insert_offset = 0;
- ul_header->csum_enabled = 0;
- ul_header->udp_ind = 0;
+ memset(ul_header, 0, sizeof(*ul_header));
priv->stats.csum_sw++;
}
diff --git a/include/linux/if_rmnet.h b/include/linux/if_rmnet.h
index 1fbb7531238b6..149d696feb520 100644
--- a/include/linux/if_rmnet.h
+++ b/include/linux/if_rmnet.h
@@ -33,17 +33,16 @@ struct rmnet_map_dl_csum_trailer {
struct rmnet_map_ul_csum_header {
__be16 csum_start_offset;
-#if defined(__LITTLE_ENDIAN_BITFIELD)
- u16 csum_insert_offset:14;
- u16 udp_ind:1;
- u16 csum_enabled:1;
-#elif defined (__BIG_ENDIAN_BITFIELD)
- u16 csum_enabled:1;
- u16 udp_ind:1;
- u16 csum_insert_offset:14;
-#else
-#error "Please fix "
-#endif
+ __be16 csum_info; /* MAP_CSUM_UL_*_FMASK */
} __aligned(1);
+/* csum_info field:
+ * ENABLED: 1 = checksum computation requested
+ * UDP: 1 = UDP checksum (zero checkum means no checksum)
+ * OFFSET:where (offset in bytes) to insert computed checksum
+ */
+#define MAP_CSUM_UL_OFFSET_FMASK GENMASK(13, 0)
+#define MAP_CSUM_UL_UDP_FMASK GENMASK(14, 14)
+#define MAP_CSUM_UL_ENABLED_FMASK GENMASK(15, 15)
+
#endif /* !(_LINUX_IF_RMNET_H_) */
--
2.20.1
