block/sed: Add helper to qualify response tokens

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 <jonathan.derrick@intel.com>
Reviewed-by: Scott Bauer <scott.bauer@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

1 files changed, 25 insertions, 36 deletions

diff --git a/block/sed-opal.c b/block/sed-opal.c
index 4675fd8eed7b..d3d6db2877b9 100644
--- a/block/sed-opal.c
+++ b/block/sed-opal.c
@@ -662,48 +662,25 @@ 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,
@@ -922,20 +899,32 @@ 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);