Messages in this thread | | | Date | Sun, 28 Apr 2013 08:11:22 +0800 | From | Herbert Xu <> | Subject | Re: [PATCH v2 1/4] Wrap crc_t10dif function all to use crypto transform framework |
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On Fri, Apr 26, 2013 at 09:44:17AM -0700, Tim Chen wrote: > > + old_tfm = crct10dif_tfm; > + crc_t10dif_newalg = true; > + /* make sure new alg flag is turned on before starting to switch tfm */ > + mb(); > + > + new_tfm = crypto_alloc_shash("crct10dif", 0, 0); > + if (IS_ERR(new_tfm)) > + goto done; > + > + if (old_tfm) > + if (crypto_tfm_alg_priority(&old_tfm->base) >= > + crypto_tfm_alg_priority(&new_tfm->base)) { > + crypto_free_shash(new_tfm); > + goto done; > + } > + crct10dif_tfm = new_tfm; > + /* make sure update to tfm pointer is completed */ > + mb(); > + crypto_free_shash(old_tfm);
This is not safe at all. You'd need to use something like RCU.
However, I think this is an overkill. Initialising it once should be enough. If someone really wanted to change things at run-time, they could always build this as a module and unload/reload it.
Cheers, -- Email: Herbert Xu <herbert@gondor.apana.org.au> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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