2020-04-30 10:40:54

by Arnd Bergmann

[permalink] [raw]
Subject: [PATCH] cxgb4/chcr: avoid -Wreturn-local-addr warning

gcc-10 warns about functions that return a pointer to a stack
variable. In chcr_write_cpl_set_tcb_ulp(), this does not actually
happen, but it's too hard to see for the compiler:

drivers/crypto/chelsio/chcr_ktls.c: In function 'chcr_write_cpl_set_tcb_ulp.constprop':
drivers/crypto/chelsio/chcr_ktls.c:760:9: error: function may return address of local variable [-Werror=return-local-addr]
760 | return pos;
| ^~~
drivers/crypto/chelsio/chcr_ktls.c:712:5: note: declared here
712 | u8 buf[48] = {0};
| ^~~

Split the middle part of the function out into a helper to make
it easier to understand by both humans and compilers, which avoids
the warning.

Fixes: 5a4b9fe7fece ("cxgb4/chcr: complete record tx handling")
Signed-off-by: Arnd Bergmann <[email protected]>
---
drivers/crypto/chelsio/chcr_ktls.c | 83 +++++++++++++++++-------------
1 file changed, 46 insertions(+), 37 deletions(-)

diff --git a/drivers/crypto/chelsio/chcr_ktls.c b/drivers/crypto/chelsio/chcr_ktls.c
index a4f2d8dae8b9..c286c60dadfd 100644
--- a/drivers/crypto/chelsio/chcr_ktls.c
+++ b/drivers/crypto/chelsio/chcr_ktls.c
@@ -686,41 +686,14 @@ int chcr_ktls_cpl_set_tcb_rpl(struct adapter *adap, unsigned char *input)
return 0;
}

-/*
- * chcr_write_cpl_set_tcb_ulp: update tcb values.
- * TCB is responsible to create tcp headers, so all the related values
- * should be correctly updated.
- * @tx_info - driver specific tls info.
- * @q - tx queue on which packet is going out.
- * @tid - TCB identifier.
- * @pos - current index where should we start writing.
- * @word - TCB word.
- * @mask - TCB word related mask.
- * @val - TCB word related value.
- * @reply - set 1 if looking for TP response.
- * return - next position to write.
- */
-static void *chcr_write_cpl_set_tcb_ulp(struct chcr_ktls_info *tx_info,
- struct sge_eth_txq *q, u32 tid,
- void *pos, u16 word, u64 mask,
+static void *__chcr_write_cpl_set_tcb_ulp(struct chcr_ktls_info *tx_info,
+ u32 tid, void *pos, u16 word, u64 mask,
u64 val, u32 reply)
{
struct cpl_set_tcb_field_core *cpl;
struct ulptx_idata *idata;
struct ulp_txpkt *txpkt;
- void *save_pos = NULL;
- u8 buf[48] = {0};
- int left;

- left = (void *)q->q.stat - pos;
- if (unlikely(left < CHCR_SET_TCB_FIELD_LEN)) {
- if (!left) {
- pos = q->q.desc;
- } else {
- save_pos = pos;
- pos = buf;
- }
- }
/* ULP_TXPKT */
txpkt = pos;
txpkt->cmd_dest = htonl(ULPTX_CMD_V(ULP_TX_PKT) | ULP_TXPKT_DEST_V(0));
@@ -745,18 +718,54 @@ static void *chcr_write_cpl_set_tcb_ulp(struct chcr_ktls_info *tx_info,
idata = (struct ulptx_idata *)(cpl + 1);
idata->cmd_more = htonl(ULPTX_CMD_V(ULP_TX_SC_NOOP));
idata->len = htonl(0);
+ pos = idata + 1;

- if (save_pos) {
- pos = chcr_copy_to_txd(buf, &q->q, save_pos,
- CHCR_SET_TCB_FIELD_LEN);
- } else {
- /* check again if we are at the end of the queue */
- if (left == CHCR_SET_TCB_FIELD_LEN)
+ return pos;
+}
+
+
+/*
+ * chcr_write_cpl_set_tcb_ulp: update tcb values.
+ * TCB is responsible to create tcp headers, so all the related values
+ * should be correctly updated.
+ * @tx_info - driver specific tls info.
+ * @q - tx queue on which packet is going out.
+ * @tid - TCB identifier.
+ * @pos - current index where should we start writing.
+ * @word - TCB word.
+ * @mask - TCB word related mask.
+ * @val - TCB word related value.
+ * @reply - set 1 if looking for TP response.
+ * return - next position to write.
+ */
+static void *chcr_write_cpl_set_tcb_ulp(struct chcr_ktls_info *tx_info,
+ struct sge_eth_txq *q, u32 tid,
+ void *pos, u16 word, u64 mask,
+ u64 val, u32 reply)
+{
+ int left = (void *)q->q.stat - pos;
+
+ if (unlikely(left < CHCR_SET_TCB_FIELD_LEN)) {
+ if (!left) {
pos = q->q.desc;
- else
- pos = idata + 1;
+ } else {
+ u8 buf[48] = {0};
+
+ __chcr_write_cpl_set_tcb_ulp(tx_info, tid, buf, word,
+ mask, val, reply);
+
+ return chcr_copy_to_txd(buf, &q->q, pos,
+ CHCR_SET_TCB_FIELD_LEN);
+ }
}

+ pos = __chcr_write_cpl_set_tcb_ulp(tx_info, tid, pos, word,
+ mask, val, reply);
+
+ /* check again if we are at the end of the queue */
+ if (left == CHCR_SET_TCB_FIELD_LEN)
+ pos = q->q.desc;
+
return pos;
}

--
2.26.0