Re: [PATCHv3 2/4] block/sed: Add helper to qualify response tokens

[Scott Bauer]

On Wed, Feb 15, 2017 at 12:42:07PM -0700, Jon Derrick wrote:
> Add helper which verifies the response token is valid and matches the
> expected value. Merges token_type and response_get_token.
> 
> Signed-off-by: Jon Derrick 
> ---
>  block/sed-opal.c | 61 
> +++-
>  1 file changed, 25 insertions(+), 36 deletions(-)
> 
> diff --git a/block/sed-opal.c b/block/sed-opal.c
> index 77623ad..d6dd604 100644
> --- a/block/sed-opal.c
> +++ b/block/sed-opal.c
> @@ -591,48 +591,25 @@ static int cmd_finalize(struct opal_dev *cmd, u32 hsn, 
> u32 tsn)
>   return 0;
>  }
>  
> -static enum opal_response_token token_type(const struct parsed_resp *resp,
> -int n)
> +static const struct opal_resp_tok *response_get_token(
> + const struct parsed_resp *resp,
> + int n)
>  {
>   const struct opal_resp_tok *tok;
>  
>   if (n >= resp->num) {
>   pr_err("Token number doesn't exist: %d, resp: %d\n",
>  n, resp->num);
> - return OPAL_DTA_TOKENID_INVALID;
> + return ERR_PTR(-EINVAL);
>   }
>  
>   tok = &resp->toks[n];
>   if (tok->len == 0) {
>   pr_err("Token length must be non-zero\n");
> - return OPAL_DTA_TOKENID_INVALID;
> + return ERR_PTR(-EINVAL);
>   }
>  
> - return tok->type;
> -}
> -
> -/*
> - * This function returns 0 in case of invalid token. One should call
> - * token_type() first to find out if the token is valid or not.
> - */
> -static enum opal_token response_get_token(const struct parsed_resp *resp,
> -   int n)
> -{
> - const struct opal_resp_tok *tok;
> -
> - if (n >= resp->num) {
> - pr_err("Token number doesn't exist: %d, resp: %d\n",
> -n, resp->num);
> - return 0;
> - }
> -
> - tok = &resp->toks[n];
> - if (tok->len == 0) {
> - pr_err("Token length must be non-zero\n");
> - return 0;
> - }
> -
> - return tok->pos[0];
> + return tok;
>  }
>  
>  static ssize_t response_parse_tiny(struct opal_resp_tok *tok,
> @@ -851,20 +828,32 @@ static u64 response_get_u64(const struct parsed_resp 
> *resp, int n)
>   return resp->toks[n].stored.u;
>  }
>  
> +static bool response_token_matches(const struct opal_resp_tok *token, u8 
> match)
> +{
> + if (IS_ERR_OR_NULL(token) ||
> + token->type != OPAL_DTA_TOKENID_TOKEN ||
> + token->pos[0] != match)
> + return false;
> + return true;
> +}
> +

This is sorta pedantic but from my reading of the code token can never be null. 
It will
either be a valid pointer or ERR_PTR(-EINVAL), but never null.
So maybe change this to IS_ERR(token) etc. Other than that little nit:

Reviewed-by: Scott Bauer 

[PATCHv3 2/4] block/sed: Add helper to qualify response tokens

[Jon Derrick]

Add helper which verifies the response token is valid and matches the
expected value. Merges token_type and response_get_token.

Signed-off-by: Jon Derrick 
---
 block/sed-opal.c | 61 +++-
 1 file changed, 25 insertions(+), 36 deletions(-)

diff --git a/block/sed-opal.c b/block/sed-opal.c
index 77623ad..d6dd604 100644
--- a/block/sed-opal.c
+++ b/block/sed-opal.c
@@ -591,48 +591,25 @@ static int cmd_finalize(struct opal_dev *cmd, u32 hsn, 
u32 tsn)
return 0;
 }
 
-static enum opal_response_token token_type(const struct parsed_resp *resp,
-  int n)
+static const struct opal_resp_tok *response_get_token(
+   const struct parsed_resp *resp,
+   int n)
 {
const struct opal_resp_tok *tok;
 
if (n >= resp->num) {
pr_err("Token number doesn't exist: %d, resp: %d\n",
   n, resp->num);
-   return OPAL_DTA_TOKENID_INVALID;
+   return ERR_PTR(-EINVAL);
}
 
tok = &resp->toks[n];
if (tok->len == 0) {
pr_err("Token length must be non-zero\n");
-   return OPAL_DTA_TOKENID_INVALID;
+   return ERR_PTR(-EINVAL);
}
 
-   return tok->type;
-}
-
-/*
- * This function returns 0 in case of invalid token. One should call
- * token_type() first to find out if the token is valid or not.
- */
-static enum opal_token response_get_token(const struct parsed_resp *resp,
- int n)
-{
-   const struct opal_resp_tok *tok;
-
-   if (n >= resp->num) {
-   pr_err("Token number doesn't exist: %d, resp: %d\n",
-  n, resp->num);
-   return 0;
-   }
-
-   tok = &resp->toks[n];
-   if (tok->len == 0) {
-   pr_err("Token length must be non-zero\n");
-   return 0;
-   }
-
-   return tok->pos[0];
+   return tok;
 }
 
 static ssize_t response_parse_tiny(struct opal_resp_tok *tok,
@@ -851,20 +828,32 @@ static u64 response_get_u64(const struct parsed_resp 
*resp, int n)
return resp->toks[n].stored.u;
 }
 
+static bool response_token_matches(const struct opal_resp_tok *token, u8 match)
+{
+   if (IS_ERR_OR_NULL(token) ||
+   token->type != OPAL_DTA_TOKENID_TOKEN ||
+   token->pos[0] != match)
+   return false;
+   return true;
+}
+
 static u8 response_status(const struct parsed_resp *resp)
 {
-   if (token_type(resp, 0) == OPAL_DTA_TOKENID_TOKEN &&
-   response_get_token(resp, 0) == OPAL_ENDOFSESSION) {
+   const struct opal_resp_tok *tok;
+
+   tok = response_get_token(resp, 0);
+   if (response_token_matches(tok, OPAL_ENDOFSESSION))
return 0;
-   }
 
if (resp->num < 5)
return DTAERROR_NO_METHOD_STATUS;
 
-   if (token_type(resp, resp->num - 1) != OPAL_DTA_TOKENID_TOKEN ||
-   token_type(resp, resp->num - 5) != OPAL_DTA_TOKENID_TOKEN ||
-   response_get_token(resp, resp->num - 1) != OPAL_ENDLIST ||
-   response_get_token(resp, resp->num - 5) != OPAL_STARTLIST)
+   tok = response_get_token(resp, resp->num - 5);
+   if (!response_token_matches(tok, OPAL_STARTLIST))
+   return DTAERROR_NO_METHOD_STATUS;
+
+   tok = response_get_token(resp, resp->num - 1);
+   if (!response_token_matches(tok, OPAL_ENDLIST))
return DTAERROR_NO_METHOD_STATUS;
 
return response_get_u64(resp, resp->num - 4);
-- 
1.8.3.1