On Fri, Jun 11, 2021 at 09:07:43PM -0700, Ira Weiny wrote: > > More recently this was added: > > 7e34e0bbc644 crypto: omap-crypto - fix userspace copied buffer access > > I'm CC'ing Tero and Herbert to see why they added the SLAB check. Probably because the generic Crypto API has the same check. This all goes back to commit 4f3e797ad07d52d34983354a77b365dfcd48c1b4 Author: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> Date: Mon Feb 9 14:22:14 2009 +1100 crypto: scatterwalk - Avoid flush_dcache_page on slab pages It's illegal to call flush_dcache_page on slab pages on a number of architectures. So this patch avoids doing so if PageSlab is true. In future we can move the flush_dcache_page call to those page cache users that actually need it. Reported-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> But I can't find any emails discussing this so let me ask Dave directly and see if he can tell us what the issue was or might have been. Thanks, -- Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt