Re: [PATCH v2] RDMA/irdma: switch to using the crc32c library
From: Eric Biggers
Date: Sun Feb 09 2025 - 10:44:24 EST
On Sun, Feb 09, 2025 at 11:12:55AM +0200, Leon Romanovsky wrote:
> On Thu, Feb 06, 2025 at 07:57:50PM -0800, Eric Biggers wrote:
> > On Thu, Feb 06, 2025 at 07:36:43PM -0800, Eric Biggers wrote:
> > > +int irdma_ieq_check_mpacrc(const void *addr, u32 len, u32 val)
> > > {
> > > - u32 crc = 0;
> > > -
> > > - crypto_shash_digest(desc, addr, len, (u8 *)&crc);
> > > - if (crc != val)
> > > + if (~crc32c(~0, addr, len) != val)
> > > return -EINVAL;
> > >
> > > return 0;
> > > }
> >
> > Sorry, I just realized this isn't actually equivalent on big endian CPUs, since
> > the byte array produced by crypto_shash_digest() used little endian byte order,
> > whereas crc32c() just returns a CPU endian value.
> >
> > And of course this broken subsystem uses u32 for the little endian values
> > instead of __le32 like the result of the kernel.
> >
> > Not sure it's worth my time to continue to try to fix this subsystem properly.
>
> There is no need to be such dramatic. You are not fixing anything by
> switch to new APIs
Exactly. That's because I dropped the patches that actually did fix real
endianness bugs, because of the pointless pushback I received -- see
https://lore.kernel.org/linux-rdma/20250127223840.67280-1-ebiggers@xxxxxxxxxx/T/#u
- Eric