[PATCH] crypto: allow to assign gfp_t for __crypto_alloc_tfm

[Jaegeuk Kim]

On Tue, May 19, 2015 at 03:15:21PM +0800, Herbert Xu wrote:
> On Tue, May 19, 2015 at 12:13:17AM -0700, Jaegeuk Kim wrote:
> >
> > The key generation is done by ext4_generate_encryption_key in
> > fs/ext4/crypto_key.c.
> > And, ext4_file_mmap and ext4_file_open trigger it.
> 
> Well that's where you should be doing crypto_alloc_ablkcipher
> and crypto_ablkcipher_setkey.
> 
> The whole point of a crypto tfm is to represent a key so any time
> you get one you should create a crypto tfm.  Carrying around a raw
> key is just wrong.

So, IMHO, it can consume memory too much, since tfm should be allocated for
every inodes and be alive until inode eviction.
Apart from giving GFP_NOFS, do you mean that it is a wrong approach?

Thanks,

> 
> Cheers,
> -- 
> Email: Herbert Xu <herbert at gondor.apana.org.au>
> Home Page: http://gondor.apana.org.au/~herbert/
> PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt