dynamic_debug: add pr_errs before -EINVALs

Ma noted that dynamic-debug is silent about many query errors, so add
pr_err()s to explain those errors, and tweak a few others.  Also parse
flags 1st, so that match-spec errs are slightly clearer.

CC: Jianpeng Ma <majianpeng@gmail.com>
CC: Joe Perches <joe@perches.com>
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Jason Baron <jbaron@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 35 insertions, 12 deletions

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index ac7d27737e42..5276b99ca650 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -223,8 +223,10 @@ static int ddebug_tokenize(char *buf, char *words[], int maxwords)
                         int quote = *buf++;
                         for (end = buf; *end && *end != quote; end++)
                                 ;
-                        if (!*end)
+                        if (!*end) {
+                                pr_err("unclosed quote: %s\n", buf);
                                 return -EINVAL; /* unclosed quote */
+                        }
                 } else {
                         for (end = buf; *end && !isspace(*end); end++)
                                 ;
@@ -232,8 +234,10 @@ static int ddebug_tokenize(char *buf, char *words[], int maxwords)
                 }
 
                 /* `buf' is start of word, `end' is one past its end */
-                if (nwords == maxwords)
+                if (nwords == maxwords) {
+                        pr_err("too many words, legal max <=%d\n", maxwords);
                         return -EINVAL; /* ran out of words[] before bytes */
+                }
                 if (*end)
                         *end++ = '\0';  /* terminate the word */
                 words[nwords++] = buf;
@@ -265,7 +269,11 @@ static inline int parse_lineno(const char *str, unsigned int *val)
                 return 0;
         }
         *val = simple_strtoul(str, &end, 10);
-        return end == NULL || end == str || *end != '\0' ? -EINVAL : 0;
+        if (end == NULL || end == str || *end != '\0') {
+                pr_err("bad line-number: %s\n", str);
+                return -EINVAL;
+        }
+        return 0;
 }
 
 /*
@@ -345,8 +353,10 @@ static int ddebug_parse_query(char *words[], int nwords,
         int rc;
 
         /* check we have an even number of words */
-        if (nwords % 2 != 0)
+        if (nwords % 2 != 0) {
+                pr_err("expecting pairs of match-spec <value>\n");
                 return -EINVAL;
+        }
         memset(query, 0, sizeof(*query));
 
         if (modname)
@@ -367,18 +377,22 @@ static int ddebug_parse_query(char *words[], int nwords,
                         char *first = words[i+1];
                         char *last = strchr(first, '-');
                         if (query->first_lineno || query->last_lineno) {
-                                pr_err("match-spec:line given 2 times\n");
+                                pr_err("match-spec: line used 2x\n");
                                 return -EINVAL;
                         }
                         if (last)
                                 *last++ = '\0';
-                        if (parse_lineno(first, &query->first_lineno) < 0)
+                        if (parse_lineno(first, &query->first_lineno) < 0) {
+                                pr_err("line-number is <0\n");
                                 return -EINVAL;
+                        }
                         if (last) {
                                 /* range <first>-<last> */
                                 if (parse_lineno(last, &query->last_lineno)
                                     < query->first_lineno) {
-                                        pr_err("last-line < 1st-line\n");
+                                        pr_err("last-line:%d < 1st-line:%d\n",
+                                                query->last_lineno,
+                                                query->first_lineno);
                                         return -EINVAL;
                                 }
                         } else {
@@ -414,6 +428,7 @@ static int ddebug_parse_flags(const char *str, unsigned int *flagsp,
                 op = *str++;
                 break;
         default:
+                pr_err("bad flag-op %c, at start of %s\n", *str, str);
                 return -EINVAL;
         }
         vpr_info("op='%c'\n", op);
@@ -425,8 +440,10 @@ static int ddebug_parse_flags(const char *str, unsigned int *flagsp,
                                 break;
                         }
                 }
-                if (i < 0)
+                if (i < 0) {
+                        pr_err("unknown flag '%c' in \"%s\"\n", *str, str);
                         return -EINVAL;
+                }
         }
         vpr_info("flags=0x%x\n", flags);
 
@@ -458,13 +475,19 @@ static int ddebug_exec_query(char *query_string, const char *modname)
         char *words[MAXWORDS];
 
         nwords = ddebug_tokenize(query_string, words, MAXWORDS);
-        if (nwords <= 0)
+        if (nwords <= 0) {
+                pr_err("tokenize failed\n");
                 return -EINVAL;
-        if (ddebug_parse_query(words, nwords-1, &query, modname))
+        }
+        /* check flags 1st (last arg) so query is pairs of spec,val */
+        if (ddebug_parse_flags(words[nwords-1], &flags, &mask)) {
+                pr_err("flags parse failed\n");
                 return -EINVAL;
-        if (ddebug_parse_flags(words[nwords-1], &flags, &mask))
+        }
+        if (ddebug_parse_query(words, nwords-1, &query, modname)) {
+                pr_err("query parse failed\n");
                 return -EINVAL;
-
+        }
         /* actually go and implement the change */
         nfound = ddebug_change(&query, flags, mask);
         vpr_info_dq(&query, nfound ? "applied" : "no-match");