Re: [PATCH] crypto: fix comparison of unsigned expression warnings
flat view
From: Jonathan Cameron <hidden>
Date: 2019-09-30 14:17:24
On Mon, 30 Sep 2019 16:49:21 +0800 Tian Tao [off-list ref] wrote:
This patch fixes the following warnings: drivers/crypto/ccree/cc_aead.c:630:5-12: WARNING: Unsigned expression compared with zero: seq_len > 0 Signed-off-by: Tian Tao <redacted>
Apologies, I should have looked into this in more depth when you asked me about it earlier rather than assuming it was 'obviously' the right fix. It's more complex than I expected given the warning, which I note is > 0 so it's not always true. I'm curious, which compiler generates that warning? So there are two ways seq_len can be set to non 0, hmac_setkey which returns a signed int, but one that is reality is >= 0. The other is xcbc_setkey which returns an unsigned int. So I would suggest that in addition to what you have here, a change to the return type of hmac_setkey in order to make it clear that never returns a negative anyway. Can also use if (seq_len) rather than if (seq_len > 0) Thanks, Jonathan
quoted hunk ↗ jump to hunk
--- drivers/crypto/ccree/cc_aead.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)diff --git a/drivers/crypto/ccree/cc_aead.c b/drivers/crypto/ccree/cc_aead.c index d3e8faa..b19291d 100644 --- a/drivers/crypto/ccree/cc_aead.c +++ b/drivers/crypto/ccree/cc_aead.c@@ -546,7 +546,7 @@ static int cc_aead_setkey(struct crypto_aead *tfm, const u8 *key, struct cc_aead_ctx *ctx = crypto_aead_ctx(tfm); struct cc_crypto_req cc_req = {}; struct cc_hw_desc desc[MAX_AEAD_SETKEY_SEQ]; - unsigned int seq_len = 0; + int seq_len = 0; struct device *dev = drvdata_to_dev(ctx->drvdata); const u8 *enckey, *authkey; int rc;