[v2] bus/dpaa: optimize device name parsing
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Commit Message
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>
---
drivers/bus/dpaa/dpaa_bus.c | 68 +++++++++++++++----------------------
1 file changed, 28 insertions(+), 40 deletions(-)
Comments
09/11/2020 14:37, Gaetan Rivet:
> 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>
Applied, thanks
@@ -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"