gcc: fix -Warray-compare

[PATCH] gcc: fix -Warray-compare

Posted by Martin Liška 3 years, 11 months ago

Fixes the following GCC warning:

drivers/net/ethernet/sun/cassini.c:1316:29: error: comparison between two arrays [-Werror=array-compare]
drivers/net/ethernet/sun/cassini.c:3783:34: error: comparison between two arrays [-Werror=array-compare]

Signed-off-by: Martin Liska <mliska@suse.cz>
---
 drivers/net/ethernet/sun/cassini.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/sun/cassini.c b/drivers/net/ethernet/sun/cassini.c
index b04a6a7bf566..435dc00d04e5 100644
--- a/drivers/net/ethernet/sun/cassini.c
+++ b/drivers/net/ethernet/sun/cassini.c
@@ -1313,7 +1313,7 @@ static void cas_init_rx_dma(struct cas *cp)
 	writel(val, cp->regs + REG_RX_PAGE_SIZE);
 
 	/* enable the header parser if desired */
-	if (CAS_HP_FIRMWARE == cas_prog_null)
+	if (&CAS_HP_FIRMWARE[0] == &cas_prog_null[0])
 		return;
 
 	val = CAS_BASE(HP_CFG_NUM_CPU, CAS_NCPUS > 63 ? 0 : CAS_NCPUS);
@@ -3780,7 +3780,7 @@ static void cas_reset(struct cas *cp, int blkflag)
 
 	/* program header parser */
 	if ((cp->cas_flags & CAS_FLAG_TARGET_ABORT) ||
-	    (CAS_HP_ALT_FIRMWARE == cas_prog_null)) {
+	    (&CAS_HP_ALT_FIRMWARE[0] == &cas_prog_null[0])) {
 		cas_load_firmware(cp, CAS_HP_FIRMWARE);
 	} else {
 		cas_load_firmware(cp, CAS_HP_ALT_FIRMWARE);
-- 
2.36.1

Re: [PATCH] gcc: fix -Warray-compare

Posted by Jakub Kicinski 3 years, 11 months ago

On Tue, 17 May 2022 16:19:16 +0200 Martin Liška wrote:
> Subject: [PATCH] gcc: fix -Warray-compare

The subject should be more like

eth: sun: cassini: remove dead code

> 
> Fixes the following GCC warning:
> 
> drivers/net/ethernet/sun/cassini.c:1316:29: error: comparison between two arrays [-Werror=array-compare]
> drivers/net/ethernet/sun/cassini.c:3783:34: error: comparison between two arrays [-Werror=array-compare]

Because AFAICT this comparison will always be true:

#define CAS_HP_ALT_FIRMWARE   cas_prog_null

Hopefully DaveM will correct if I'm getting this wrong :)

[PATCH v2] eth: sun: cassini: remove dead code

Posted by Martin Liška 3 years, 11 months ago

Fixes the following GCC warning:

drivers/net/ethernet/sun/cassini.c:1316:29: error: comparison between two arrays [-Werror=array-compare]
drivers/net/ethernet/sun/cassini.c:3783:34: error: comparison between two arrays [-Werror=array-compare]

Note that 2 arrays should be compared by comparing of their addresses:
note: use ‘&cas_prog_workaroundtab[0] == &cas_prog_null[0]’ to compare the addresses

Signed-off-by: Martin Liska <mliska@suse.cz>
---
 drivers/net/ethernet/sun/cassini.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/sun/cassini.c b/drivers/net/ethernet/sun/cassini.c
index b04a6a7bf566..435dc00d04e5 100644
--- a/drivers/net/ethernet/sun/cassini.c
+++ b/drivers/net/ethernet/sun/cassini.c
@@ -1313,7 +1313,7 @@ static void cas_init_rx_dma(struct cas *cp)
 	writel(val, cp->regs + REG_RX_PAGE_SIZE);
 
 	/* enable the header parser if desired */
-	if (CAS_HP_FIRMWARE == cas_prog_null)
+	if (&CAS_HP_FIRMWARE[0] == &cas_prog_null[0])
 		return;
 
 	val = CAS_BASE(HP_CFG_NUM_CPU, CAS_NCPUS > 63 ? 0 : CAS_NCPUS);
@@ -3780,7 +3780,7 @@ static void cas_reset(struct cas *cp, int blkflag)
 
 	/* program header parser */
 	if ((cp->cas_flags & CAS_FLAG_TARGET_ABORT) ||
-	    (CAS_HP_ALT_FIRMWARE == cas_prog_null)) {
+	    (&CAS_HP_ALT_FIRMWARE[0] == &cas_prog_null[0])) {
 		cas_load_firmware(cp, CAS_HP_FIRMWARE);
 	} else {
 		cas_load_firmware(cp, CAS_HP_ALT_FIRMWARE);
-- 
2.36.1