From: Eric Biggers <ebiggers@google.com>

Instead of calling __skb_checksum() with a skb_checksum_ops struct that
does CRC32C, just call the new function skb_crc32c().  This is faster
and simpler.

Signed-off-by: Eric Biggers <ebiggers@google.com>
---
 drivers/infiniband/sw/siw/Kconfig |  1 +
 drivers/infiniband/sw/siw/siw.h   | 22 +---------------------
 2 files changed, 2 insertions(+), 21 deletions(-)

diff --git a/drivers/infiniband/sw/siw/Kconfig b/drivers/infiniband/sw/siw/Kconfig
index ae4a953e2a03..186f182b80e7 100644
--- a/drivers/infiniband/sw/siw/Kconfig
+++ b/drivers/infiniband/sw/siw/Kconfig
@@ -1,10 +1,11 @@
 config RDMA_SIW
 	tristate "Software RDMA over TCP/IP (iWARP) driver"
 	depends on INET && INFINIBAND
 	depends on INFINIBAND_VIRT_DMA
 	select CRC32
+	select NET_CRC32C
 	help
 	This driver implements the iWARP RDMA transport over
 	the Linux TCP/IP network stack. It enables a system with a
 	standard Ethernet adapter to interoperate with a iWARP
 	adapter or with another system running the SIW driver.
diff --git a/drivers/infiniband/sw/siw/siw.h b/drivers/infiniband/sw/siw/siw.h
index 385067e07faf..d9e5a2e4c471 100644
--- a/drivers/infiniband/sw/siw/siw.h
+++ b/drivers/infiniband/sw/siw/siw.h
@@ -691,33 +691,13 @@ static inline void siw_crc_oneshot(const void *data, size_t len, u8 out[4])
 	siw_crc_init(&crc);
 	siw_crc_update(&crc, data, len);
 	return siw_crc_final(&crc, out);
 }
 
-static inline __wsum siw_csum_update(const void *buff, int len, __wsum sum)
-{
-	return (__force __wsum)crc32c((__force __u32)sum, buff, len);
-}
-
-static inline __wsum siw_csum_combine(__wsum csum, __wsum csum2, int offset,
-				      int len)
-{
-	return (__force __wsum)crc32c_combine((__force __u32)csum,
-					      (__force __u32)csum2, len);
-}
-
 static inline void siw_crc_skb(struct siw_rx_stream *srx, unsigned int len)
 {
-	const struct skb_checksum_ops siw_cs_ops = {
-		.update = siw_csum_update,
-		.combine = siw_csum_combine,
-	};
-	__wsum crc = (__force __wsum)srx->mpa_crc;
-
-	crc = __skb_checksum(srx->skb, srx->skb_offset, len, crc,
-			     &siw_cs_ops);
-	srx->mpa_crc = (__force u32)crc;
+	srx->mpa_crc = skb_crc32c(srx->skb, srx->skb_offset, len, srx->mpa_crc);
 }
 
 #define siw_dbg(ibdev, fmt, ...)                                               \
 	ibdev_dbg(ibdev, "%s: " fmt, __func__, ##__VA_ARGS__)
 
-- 
2.49.0

On 5/10/25 5:41 PM, Eric Biggers wrote:
> Instead of calling __skb_checksum() with a skb_checksum_ops struct that
> does CRC32C, just call the new function skb_crc32c().  This is faster
> and simpler.
Bernard, since you are the owner and author of the siw driver, please 
help with reviewing this patch.

Eric, do you already have a test case for the siw driver? If not,
multiple tests in the blktests framework use this driver intensively,
including the SRP tests that I wrote myself. See also
https://github.com/osandov/blktests.

Bart.

On Thu, May 15, 2025 at 01:02:20PM -0700, Bart Van Assche wrote:
> On 5/10/25 5:41 PM, Eric Biggers wrote:
> > Instead of calling __skb_checksum() with a skb_checksum_ops struct that
> > does CRC32C, just call the new function skb_crc32c().  This is faster
> > and simpler.
> Bernard, since you are the owner and author of the siw driver, please help
> with reviewing this patch.
> 
> Eric, do you already have a test case for the siw driver? If not,
> multiple tests in the blktests framework use this driver intensively,
> including the SRP tests that I wrote myself. See also
> https://github.com/osandov/blktests.

No.  I'll try that out when I have a chance.

If the developers/maintainers of the driver could help test it, that would be a
lot easier though.  I've been cleaning up the CRC calls across the whole kernel,
and it gets time-consuming when individual subsystems insist on me running their
custom test suite(s) and providing subsystem-specific benchmarks.

- Eric