[PATCH v3 13/18] tftp: detect out-of-memory situations

[Enrico Scholz <enrico.scholz@sigma-chemnitz.de>]

it should never happen due to the program logic; but detect a failed
kfifo_put() just in case...

Signed-off-by: Enrico Scholz <enrico.scholz@sigma-chemnitz.de>
---
 fs/tftp.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/fs/tftp.c b/fs/tftp.c
index 2bb9361d8929..5c3e56a6cb22 100644
--- a/fs/tftp.c
+++ b/fs/tftp.c
@@ -263,6 +263,8 @@ static void tftp_timer_reset(struct file_priv *priv)
 static void tftp_put_data(struct file_priv *priv, uint16_t block,
 			  void const *pkt, size_t len)
 {
+	unsigned int sz;
+
 	if (len > priv->blocksize) {
 		pr_warn("tftp: oversized packet (%zu > %d) received\n",
 			len, priv->blocksize);
@@ -271,9 +273,14 @@ static void tftp_put_data(struct file_priv *priv, uint16_t block,
 
 	priv->last_block = block;
 
-	kfifo_put(priv->fifo, pkt, len);
+	sz = kfifo_put(priv->fifo, pkt, len);
 
-	if (len < priv->blocksize) {
+	if (sz != len) {
+		pr_err("tftp: not enough room in kfifo (only %u out of %zu written\n",
+		       sz, len);
+		priv->err = -ENOMEM;
+		priv->state = STATE_DONE;
+	} else if (len < priv->blocksize) {
 		tftp_send(priv);
 		priv->err = 0;
 		priv->state = STATE_DONE;
-- 
2.37.1