Re: [PATCHv4 2/4] block/sed: Add helper to qualify response tokens

[Christoph Hellwig]

On Wed, Feb 15, 2017 at 02:45:55PM -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 
> Reviewed-by: Scott Bauer 

Looks fine,

Reviewed-by: Christoph Hellwig 

[PATCHv4 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 
Reviewed-by: Scott Bauer 
---
 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..00673cf 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(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