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[83.36.179.126]) by smtp.gmail.com with ESMTPSA id f15sm2454435wmj.44.2020.07.23.01.46.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 23 Jul 2020 01:46:28 -0700 (PDT) From: Jorge Ramirez-Ortiz To: jorge@foundries.io, sumit.garg@linaro.org, mpm@selenic.com, herbert@gondor.apana.org.au Cc: jens.wiklander@linaro.org, arnd@arndb.de, ricardo@foundries.io, mike@foundries.io, gregkh@linuxfoundation.org, op-tee@lists.trustedfirmware.org, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCHv2 2/2] hwrng: optee: fix wait use case Date: Thu, 23 Jul 2020 10:46:22 +0200 Message-Id: <20200723084622.31134-2-jorge@foundries.io> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200723084622.31134-1-jorge@foundries.io> References: <20200723084622.31134-1-jorge@foundries.io> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The current code waits for data to be available before attempting a second read. However the second read would not be executed as the while loop exits. This fix does not wait if all data has been read and reads a second time if only partial data was retrieved on the first read. This fix also does not attempt to read if not data is requested. Signed-off-by: Jorge Ramirez-Ortiz --- v2: tidy up the while loop to avoid reading when no data is requested drivers/char/hw_random/optee-rng.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/char/hw_random/optee-rng.c b/drivers/char/hw_random/optee-rng.c index 5bc4700c4dae..a99d82949981 100644 --- a/drivers/char/hw_random/optee-rng.c +++ b/drivers/char/hw_random/optee-rng.c @@ -122,14 +122,14 @@ static int optee_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait) if (max > MAX_ENTROPY_REQ_SZ) max = MAX_ENTROPY_REQ_SZ; - while (read == 0) { + while (read < max) { rng_size = get_optee_rng_data(pvt_data, data, (max - read)); data += rng_size; read += rng_size; if (wait && pvt_data->data_rate) { - if (timeout-- == 0) + if ((timeout-- == 0) || (read == max)) return read; msleep((1000 * (max - read)) / pvt_data->data_rate); } else { -- 2.17.1