Use the sgl_alloc() and sgl_free() functions instead of open coding
these functions.
Signed-off-by: NBart Van Assche <bart.vanassche@wdc.com>
Acked-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NJens Axboe <axboe@kernel.dk>