nss-packages-LiBwrt/qca-nss-drv/patches-11.4/0028-backport-12.5-fix-greredir-stats-partial-copy.patch

From 472f636bb62f53312d170d28df8961cbfb7479d4 Mon Sep 17 00:00:00 2001
From: Nitin Shetty <quic_nitinsj@quicinc.com>
Date: Wed, 22 Nov 2023 19:24:58 +0530
Subject: [PATCH 07/31] [qca-nss-drv] fix greredir stats partial copy issue.

If the kernel passes smaller user buffer to copy stats
than required, copy the partial content from local  buffer
and in next call copy the remaining content.

Change-Id: Ice199d193ddb098407de5876a63fff8380894408
Signed-off-by: Nitin Shetty <quic_nitinsj@quicinc.com>
---
 nss_core.h            | 10 +++++
 nss_gre_redir_stats.c | 90 ++++++++++++++++++++++++++++++++++++-------
 2 files changed, 86 insertions(+), 14 deletions(-)

--- a/nss_core.h
+++ b/nss_core.h
@@ -504,6 +504,15 @@ struct nss_ctx_instance {
 };
 
 /*
+ * NSS stats read context
+ */
+struct nss_stats_buff {
+	uint16_t msg_len;		/* Length of message copied */
+	char *msg_base_ptr;		/* base buffer pointer */
+	char *msg_cur_ptr;		/* current buffer pointer */
+};
+
+/*
  * Main NSS context structure (singleton)
  */
 struct nss_top_instance {
@@ -679,6 +688,7 @@ struct nss_top_instance {
 	struct nss_hal_ops *hal_ops;	/* nss_hal ops for this target platform */
 	struct nss_data_plane_ops *data_plane_ops;
 					/* nss_data_plane ops for this target platform */
+	struct nss_stats_buff stats_buff;
 };
 
 #if (NSS_PKT_STATS_ENABLED == 1)
--- a/nss_gre_redir_stats.c
+++ b/nss_gre_redir_stats.c
@@ -53,6 +53,38 @@ bool nss_gre_redir_stats_get(int index,
 EXPORT_SYMBOL(nss_gre_redir_stats_get);
 
 /*
+ * nss_gre_redir_stats_copy_rem_buf()
+ *	Copy the local buffer to kernel user buffer
+ */
+static int nss_gre_redir_stats_copy_rem_buf(struct nss_stats_buff *ws, char *buffer,
+					    size_t length, int *total_read)
+{
+	int bytes_read;
+	int return_value = 0;
+
+	bytes_read = ws->msg_len;
+
+	/*
+	 * Calculate total bytes read to the current buffer
+	 */
+	if ((bytes_read + *total_read) >= length) {
+		bytes_read = length - *total_read;
+		return_value = -ENOMEM;
+	}
+
+	if (copy_to_user(buffer + *total_read, ws->msg_cur_ptr, bytes_read)) {
+		return -EFAULT;
+	}
+
+	ws->msg_len -= bytes_read;
+	ws->msg_cur_ptr += bytes_read;
+
+	*total_read += bytes_read;
+
+	return return_value;
+}
+
+/*
  * nss_gre_redir_stats_read()
  *	READ gre_redir tunnel stats.
  */
@@ -67,14 +99,27 @@ static ssize_t nss_gre_redir_stats_read(
 	size_t size_al = NSS_STATS_MAX_STR_LENGTH * max_output_lines * NSS_GRE_REDIR_MAX_INTERFACES;
 	struct nss_stats_data *data = fp->private_data;
 	struct nss_gre_redir_tunnel_stats stats;
-	ssize_t bytes_read = 0;
-	size_t size_wr = 0;
+	struct nss_stats_buff *ws;
+	int bytes_read = 0;
 	int index = 0;
+	int status = 0;
+
+	size_al = PAGE_SIZE;
+
+	ws = (struct nss_stats_buff *)&nss_top_main.stats_buff;
 
-	char *lbuf = kzalloc(size_al, GFP_KERNEL);
-	if (unlikely(!lbuf)) {
-		nss_warning("Could not allocate memory for local statistics buffer");
-		return 0;
+	if (ws->msg_len) {
+		status = nss_gre_redir_stats_copy_rem_buf(ws, ubuf, sz, &bytes_read);
+		if (status < 0) {
+			goto done;
+		}
+	} else {
+		ws->msg_base_ptr = kmalloc(size_al, GFP_KERNEL);
+		if (!ws->msg_base_ptr) {
+			nss_warning("Could not allocate memory for local statistics buffer");
+			return -ENOMEM;
+		}
+		ws->msg_cur_ptr = ws->msg_base_ptr;
 	}
 
 	if (data) {
@@ -85,8 +130,7 @@ static ssize_t nss_gre_redir_stats_read(
 	 * If we are done accomodating all the GRE_REDIR tunnels.
 	 */
 	if (index >= NSS_GRE_REDIR_MAX_INTERFACES) {
-		kfree(lbuf);
-		return 0;
+		goto done;
 	}
 
 	for (; index < NSS_GRE_REDIR_MAX_INTERFACES; index++) {
@@ -100,18 +144,36 @@ static ssize_t nss_gre_redir_stats_read(
 			continue;
 		}
 
-		size_wr += nss_stats_banner(lbuf, size_wr, size_al, "gre_redir stats", NSS_STATS_SINGLE_CORE);
-		size_wr += scnprintf(lbuf + size_wr, size_al - size_wr, "\nTunnel stats for %s\n", stats.dev->name);
-		size_wr += nss_stats_print("gre_redir", NULL, NSS_STATS_SINGLE_INSTANCE, nss_gre_redir_strings_stats,
-					&stats.tstats.rx_packets, NSS_GRE_REDIR_STATS_MAX, lbuf, size_wr, size_al);
+		ws->msg_cur_ptr = ws->msg_base_ptr;
+
+		ws->msg_len = nss_stats_banner(ws->msg_base_ptr, ws->msg_len, size_al, "gre_redir stats", NSS_STATS_SINGLE_CORE);
+		ws->msg_len += scnprintf(ws->msg_base_ptr + ws->msg_len, size_al - ws->msg_len, "\nTunnel stats for %s\n", stats.dev->name);
+		ws->msg_len += nss_stats_print("gre_redir", NULL, NSS_STATS_SINGLE_INSTANCE, nss_gre_redir_strings_stats,
+					&stats.tstats.rx_packets, NSS_GRE_REDIR_STATS_MAX, ws->msg_base_ptr, ws->msg_len, size_al);
+
+		status = nss_gre_redir_stats_copy_rem_buf(ws, ubuf, sz, &bytes_read);
+
+		if (status < 0) {
+			index++;
+			break;
+		}
+
 	}
 
-	bytes_read = simple_read_from_buffer(ubuf, sz, ppos, lbuf, strlen(lbuf));
 	if (data) {
 		data->index = index;
 	}
 
-	kfree(lbuf);
+done:
+	if (status == -EFAULT) {
+		bytes_read = -EFAULT;
+	}
+
+	if (!ws->msg_len && ws->msg_base_ptr) {
+		kfree(ws->msg_base_ptr);
+		ws->msg_base_ptr = NULL;
+	}
+
 	return bytes_read;
 }