bus/dpaa: optimize device name parsing

Device name parsing is done on all buses during device iterations at
either EAL or ethdev levels.

When a bus implements device name parsing slowly, all iterations are
impacted. Efficient implementation is important.

The DPAA bus device name parsing has two issues: it allocates dynamic
memory and uses snprintf without a real need for it. Both can be
avoided, which improves the parsing performance.

The function is also simpler and shorter.

Signed-off-by: Gaetan Rivet <grive@u256.net>

diff --git a/drivers/bus/dpaa/dpaa_bus.c b/drivers/bus/dpaa/dpaa_bus.c
index 3098e23..f39d6e2 100644 (file)
--- a/drivers/bus/dpaa/dpaa_bus.c
+++ b/drivers/bus/dpaa/dpaa_bus.c
@@ -385,12 +385,10 @@ dpaa_portal_finish(void *arg)
 }
 
 static int
-rte_dpaa_bus_parse(const char *name, void *out_name)
+rte_dpaa_bus_parse(const char *name, void *out)
 {
-       int i, j;
-       int max_fman = 2, max_macs = 16;
-       char *dup_name;
-       char *sep = NULL;
+       unsigned int i, j;
+       size_t delta;
 
        /* There are two ways of passing device name, with and without
         * separator. "dpaa_bus:fm1-mac3" with separator, and "fm1-mac3"
@@ -399,46 +397,36 @@ rte_dpaa_bus_parse(const char *name, void *out_name)
         */
        DPAA_BUS_DEBUG("Parse device name (%s)", name);
 
-       /* Check for dpaa_bus:fm1-mac3 style */
-       dup_name = strdup(name);
-       sep = strchr(dup_name, ':');
-       if (!sep)
-               /* If not, check for name=fm1-mac3 style */
-               sep = strchr(dup_name, '=');
+       delta = 0;
+       if (strncmp(name, "dpaa_bus:", 9) == 0) {
+               delta = 9;
+       } else if (strncmp(name, "name=", 5) == 0) {
+               delta = 5;
+       }
 
-       if (sep)
-               /* jump over the seprator */
-               sep = (char *) (sep + 1);
-       else
-               sep = dup_name;
-
-       for (i = 0; i < max_fman; i++) {
-               for (j = 0; j < max_macs; j++) {
-                       char fm_name[16];
-                       snprintf(fm_name, 16, "fm%d-mac%d", i, j);
-                       if (strcmp(fm_name, sep) == 0) {
-                               if (out_name)
-                                       strcpy(out_name, sep);
-                               free(dup_name);
-                               return 0;
-                       }
-               }
+       if (sscanf(&name[delta], "fm%u-mac%u", &i, &j) != 2 ||
+           i >= 2 || j >= 16) {
+               return -EINVAL;
        }
 
-       for (i = 0; i < RTE_LIBRTE_DPAA_MAX_CRYPTODEV; i++) {
-               char sec_name[16];
-
-               snprintf(sec_name, 16, "dpaa_sec-%d", i+1);
-               if (strcmp(sec_name, sep) == 0) {
-                       if (out_name)
-                               strcpy(out_name, sep);
-                       free(dup_name);
-                       return 0;
-               }
+       if (out != NULL) {
+               char *out_name = out;
+               const size_t max_name_len = sizeof("fm.-mac..") - 1;
+
+               /* Do not check for truncation, either name ends with
+                * '\0' or the device name is followed by parameters and there
+                * will be a ',' instead. Not copying past this comma is not an
+                * error.
+                */
+               strlcpy(out_name, &name[delta], max_name_len + 1);
+
+               /* Second digit of mac%u could instead be ','. */
+               if ((strlen(out_name) == max_name_len) &&
+                   out_name[max_name_len] == ',')
+                       out_name[max_name_len] = '\0';
        }
 
-       free(dup_name);
-       return -EINVAL;
+       return 0;
 }
 
 #define DPAA_DEV_PATH1 "/sys/devices/platform/soc/soc:fsl,dpaa"