Quoting Jani Nikula (2024-11-27 10:18:38-03:00)
>Hand rolling the buffer overflow handling with snprintf() is a bit
>tedious. The seq_buf interface is made for this. Switch to it.
Cool! Today I learned a new kernel interface. :-)
>
>Use struct intel_display while at it.
>
>Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
>---
> drivers/gpu/drm/i915/display/intel_dp.c | 36 ++++++++++---------------
> 1 file changed, 14 insertions(+), 22 deletions(-)
>
>diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
>index 053a9a4182e7..4471c8fcd478 100644
>--- a/drivers/gpu/drm/i915/display/intel_dp.c
>+++ b/drivers/gpu/drm/i915/display/intel_dp.c
>@@ -28,6 +28,7 @@
> #include <linux/export.h>
> #include <linux/i2c.h>
> #include <linux/notifier.h>
>+#include <linux/seq_buf.h>
> #include <linux/slab.h>
> #include <linux/sort.h>
> #include <linux/string_helpers.h>
>@@ -1506,41 +1507,32 @@ bool intel_dp_source_supports_tps4(struct drm_i915_private *i915)
> return DISPLAY_VER(i915) >= 10;
> }
>
>-static void snprintf_int_array(char *str, size_t len,
>- const int *array, int nelem)
>+static void seq_buf_print_array(struct seq_buf *s, const int *array, int nelem)
> {
> int i;
>
>- str[0] = '\0';
>-
>- for (i = 0; i < nelem; i++) {
>- int r = snprintf(str, len, "%s%d", i ? ", " : "", array[i]);
>- if (r >= len)
>- return;
>- str += r;
>- len -= r;
>- }
>+ for (i = 0; i < nelem; i++)
>+ seq_buf_printf(s, "%s%d", i ? ", " : "", array[i]);
> }
>
> static void intel_dp_print_rates(struct intel_dp *intel_dp)
> {
>- struct drm_i915_private *i915 = dp_to_i915(intel_dp);
>- char str[128]; /* FIXME: too big for stack? */
>+ struct intel_display *display = to_intel_display(intel_dp);
>+ DECLARE_SEQ_BUF(s, 128); /* FIXME: too big for stack? */
I wonder if just using drm_dbg_printer() would make things simpler,
without requiring a buffer.
Anyway, the patch looks good to me, so:
Reviewed-by: Gustavo Sousa <gustavo.sousa@xxxxxxxxx>
>
> if (!drm_debug_enabled(DRM_UT_KMS))
> return;
>
>- snprintf_int_array(str, sizeof(str),
>- intel_dp->source_rates, intel_dp->num_source_rates);
>- drm_dbg_kms(&i915->drm, "source rates: %s\n", str);
>+ seq_buf_print_array(&s, intel_dp->source_rates, intel_dp->num_source_rates);
>+ drm_dbg_kms(display->drm, "source rates: %s\n", seq_buf_str(&s));
>
>- snprintf_int_array(str, sizeof(str),
>- intel_dp->sink_rates, intel_dp->num_sink_rates);
>- drm_dbg_kms(&i915->drm, "sink rates: %s\n", str);
>+ seq_buf_clear(&s);
>+ seq_buf_print_array(&s, intel_dp->sink_rates, intel_dp->num_sink_rates);
>+ drm_dbg_kms(display->drm, "sink rates: %s\n", seq_buf_str(&s));
>
>- snprintf_int_array(str, sizeof(str),
>- intel_dp->common_rates, intel_dp->num_common_rates);
>- drm_dbg_kms(&i915->drm, "common rates: %s\n", str);
>+ seq_buf_clear(&s);
>+ seq_buf_print_array(&s, intel_dp->common_rates, intel_dp->num_common_rates);
>+ drm_dbg_kms(display->drm, "common rates: %s\n", seq_buf_str(&s));
> }
>
> static int forced_link_rate(struct intel_dp *intel_dp)
>--
>2.39.5
>
