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From: Jason Wang <jasowang@redhat.com>
To: qemu-devel@nongnu.org
Cc: Peter Maydell <peter.maydell@linaro.org>,
	Jason Wang <jasowang@redhat.com>
Subject: [PULL 06/12] hw/net/npcm_gmac.c: Drop 'buf' local variable
Date: Mon, 21 Jul 2025 13:59:21 +0800	[thread overview]
Message-ID: <20250721055927.75951-7-jasowang@redhat.com> (raw)
In-Reply-To: <20250721055927.75951-1-jasowang@redhat.com>

From: Peter Maydell <peter.maydell@linaro.org>

We use the local variable 'buf' only when we call dma_memory_read(),
and it is always set to &tx_send_buffer[prev_buf_size] immediately
before both of those calls.  So remove the variable and pass
tx_send_buffer + prev_buf_size to dma_memory_read().

This fixes in passing a place where we set buf = tx_send_buffer
but never used that value because we always updated buf to
something else later before using it.

Coverity: CID 1534027
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 hw/net/npcm_gmac.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/hw/net/npcm_gmac.c b/hw/net/npcm_gmac.c
index 0c17ae9b2a..5e32cd3edf 100644
--- a/hw/net/npcm_gmac.c
+++ b/hw/net/npcm_gmac.c
@@ -516,7 +516,6 @@ static void gmac_try_send_next_packet(NPCMGMACState *gmac)
     uint32_t desc_addr;
     struct NPCMGMACTxDesc tx_desc;
     uint32_t tx_buf_addr, tx_buf_len;
-    uint8_t *buf = tx_send_buffer;
     uint32_t prev_buf_size = 0;
     int csum = 0;
 
@@ -567,16 +566,15 @@ static void gmac_try_send_next_packet(NPCMGMACState *gmac)
         tx_buf_addr = tx_desc.tdes2;
         gmac->regs[R_NPCM_DMA_CUR_TX_BUF_ADDR] = tx_buf_addr;
         tx_buf_len = TX_DESC_TDES1_BFFR1_SZ_MASK(tx_desc.tdes1);
-        buf = &tx_send_buffer[prev_buf_size];
 
         if ((prev_buf_size + tx_buf_len) > tx_buffer_size) {
             tx_buffer_size = prev_buf_size + tx_buf_len;
             tx_send_buffer = g_realloc(tx_send_buffer, tx_buffer_size);
-            buf = &tx_send_buffer[prev_buf_size];
         }
 
         /* step 5 */
-        if (dma_memory_read(&address_space_memory, tx_buf_addr, buf,
+        if (dma_memory_read(&address_space_memory, tx_buf_addr,
+                            tx_send_buffer + prev_buf_size,
                             tx_buf_len, MEMTXATTRS_UNSPECIFIED)) {
             qemu_log_mask(LOG_GUEST_ERROR, "%s: Failed to read packet @ 0x%x\n",
                         __func__, tx_buf_addr);
@@ -589,15 +587,14 @@ static void gmac_try_send_next_packet(NPCMGMACState *gmac)
             tx_buf_addr = tx_desc.tdes3;
             gmac->regs[R_NPCM_DMA_CUR_TX_BUF_ADDR] = tx_buf_addr;
             tx_buf_len = TX_DESC_TDES1_BFFR2_SZ_MASK(tx_desc.tdes1);
-            buf = &tx_send_buffer[prev_buf_size];
 
             if ((prev_buf_size + tx_buf_len) > tx_buffer_size) {
                 tx_buffer_size = prev_buf_size + tx_buf_len;
                 tx_send_buffer = g_realloc(tx_send_buffer, tx_buffer_size);
-                buf = &tx_send_buffer[prev_buf_size];
             }
 
-            if (dma_memory_read(&address_space_memory, tx_buf_addr, buf,
+            if (dma_memory_read(&address_space_memory, tx_buf_addr,
+                                tx_send_buffer + prev_buf_size,
                                 tx_buf_len, MEMTXATTRS_UNSPECIFIED)) {
                 qemu_log_mask(LOG_GUEST_ERROR,
                               "%s: Failed to read packet @ 0x%x\n",
@@ -615,7 +612,6 @@ static void gmac_try_send_next_packet(NPCMGMACState *gmac)
             net_checksum_calculate(tx_send_buffer, length, csum);
             qemu_send_packet(qemu_get_queue(gmac->nic), tx_send_buffer, length);
             trace_npcm_gmac_packet_sent(DEVICE(gmac)->canonical_path, length);
-            buf = tx_send_buffer;
             prev_buf_size = 0;
         }
 
-- 
2.42.0



  parent reply	other threads:[~2025-07-21  6:06 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-07-21  5:59 [PULL 00/12] Net patches Jason Wang
2025-07-21  5:59 ` [PULL 01/12] net/tap: drop too small packets Jason Wang
2025-07-21  5:59 ` [PULL 02/12] tap: fix net_init_tap() return code Jason Wang
2025-07-21  5:59 ` [PULL 03/12] hw/net/npcm_gmac.c: Send the right data for second packet in a row Jason Wang
2025-07-21  5:59 ` [PULL 04/12] hw/net/npcm_gmac.c: Unify length and prev_buf_size variables Jason Wang
2025-07-21  5:59 ` [PULL 05/12] hw/net/npcm_gmac.c: Correct test for when to reallocate packet buffer Jason Wang
2025-07-21  5:59 ` Jason Wang [this message]
2025-07-21  5:59 ` [PULL 07/12] net/passt: Remove unused "err" from passt_vhost_user_event() (CID 1612375) Jason Wang
2025-07-21  5:59 ` [PULL 08/12] net/vhost-user: Remove unused "err" from net_vhost_user_event() (CID 1612372) Jason Wang
2025-07-21  5:59 ` [PULL 09/12] net/passt: Remove dead code in passt_vhost_user_start error path (CID 1612371) Jason Wang
2025-07-21  5:59 ` [PULL 10/12] net/passt: Check return value of g_remove() in net_passt_cleanup() (CID 1612369) Jason Wang
2025-07-21  5:59 ` [PULL 11/12] net/passt: Initialize "error" variable in net_passt_send() (CID 1612368) Jason Wang
2025-07-21  5:59 ` [PULL 12/12] net/vhost-user: Remove unused "err" from chr_closed_bh() (CID 1612365) Jason Wang
2025-07-21 13:59 ` [PULL 00/12] Net patches Stefan Hajnoczi

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