Re: [PATCH v3] octeontx2-af: use seq_file for rsrc_alloc debugfs

The rsrc_alloc debugfs reader writes rows directly to userspace without
respecting the caller's read count. It also uses the current row length as
the userspace stride, which can corrupt output when rows have different
widths.

Use seq_file to handle userspace buffer sizes, offsets, and partial reads.

The LF list formatter is used both to determine the widest column and skip
PF/VF rows with no resources, and to emit the final table. Let it measure
the formatted length when no seq_file is supplied, and write directly to
the seq_file during rendering. This preserves the pre-scan behavior while
removing the temporary string buffers.

Fixes: 23205e6d06d4 ("octeontx2-af: Dump current resource provisioning status")
Assisted-by: LLM Codex
Signed-off-by: Heyang Tan <redacted>

Changes in v3:
- Format LF lists directly in the seq_file buffer and remove temporary buffers.
- Measure, rather than emit, LF lists during width calculation and row scans.
- Explain the two formatter modes in a code comment.
- Preserve column alignment with seq_setwidth() and seq_pad().
- Reorder local declarations in reverse Christmas tree order.

Link: https://lore.kernel.org/netdev/20260906141129.1730-1-thy15333007817@163.com/ (local)
---
 .../marvell/octeontx2/af/rvu_debugfs.c        | 114 +++++++++++-------
 1 file changed, 69 insertions(+), 45 deletions(-)

diff --git a/drivers/net/ethernet/marvell/octeontx2/af/rvu_debugfs.c b/drivers/net/ethernet/marvell/octeontx2/af/rvu_debugfs.c
index fcbf4ba0e10a..1f177851e76d 100644
--- a/drivers/net/ethernet/marvell/octeontx2/af/rvu_debugfs.c
+++ b/drivers/net/ethernet/marvell/octeontx2/af/rvu_debugfs.c

@@ -646,10 +646,29 @@ static ssize_t rvu_dbg_lmtst_map_table_display(struct file *filp,

 RVU_DEBUG_FOPS(lmtst_map_table, lmtst_map_table_display, NULL);

-static void get_lf_str_list(const struct rvu_block *block, int pcifunc,
-			    char *lfs)
+static int get_num_digits(int number)
 {
-	int lf = 0, seq = 0, len = 0, prev_lf = block->lf.max;
+	int width = 1;
+
+	while (number >= 10) {
+		number /= 10;
+		width++;
+	}
+
+	return width;
+}