linux-kernel - [PATCH v2] isdn: hfc_{pci,sx}: Avoid empty body if statements

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Message-Id: <20181018034935.16819-1-natechancellor@gmail.com>
Date:   Wed, 17 Oct 2018 20:49:36 -0700
From:   Nathan Chancellor <natechancellor@...il.com>
To:     Karsten Keil <isdn@...ux-pingi.de>,
        "David S. Miller" <davem@...emloft.net>
Cc:     netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        Masahiro Yamada <yamada.masahiro@...ionext.com>,
        Nathan Chancellor <natechancellor@...il.com>
Subject: [PATCH v2] isdn: hfc_{pci,sx}: Avoid empty body if statements

Clang warns:

drivers/isdn/hisax/hfc_pci.c:131:34: error: if statement has empty body
[-Werror,-Wempty-body]
        if (Read_hfc(cs, HFCPCI_INT_S1));
                                        ^
drivers/isdn/hisax/hfc_pci.c:131:34: note: put the semicolon on a
separate line to silence this warning

In my attempt to hide the warnings because I thought they didn't serve
any purpose[1], Masahiro Yamada pointed out that {Read,Write}_hfc in
hci_pci.c should be using a standard register access method; otherwise,
the compiler will just remove the if statements.

For hfc_pci, use the versions of {Read,Write}_hfc found in
drivers/isdn/hardware/mISDN/hfc_pCI.h then remove the empty if statements.

For hfc_sx, {Read,Write}_hfc are already use a proper register accessor
(inb, outb) so just remove the unnecessary if statements.

[1]: https://lore.kernel.org/lkml/20181016021454.11953-1-natechancellor@gmail.com/

Link: https://github.com/ClangBuiltLinux/linux/issues/66
Suggested-by: Masahiro Yamada <yamada.masahiro@...ionext.com>
Signed-off-by: Nathan Chancellor <natechancellor@...il.com>
---

v1 -> v2:

* Remove unnecessary cast to void, just remove if statements (thanks to
  review from Masahiro).

* Clean up commit message.

 drivers/isdn/hisax/hfc_pci.c | 6 +++---
 drivers/isdn/hisax/hfc_pci.h | 4 ++--
 drivers/isdn/hisax/hfc_sx.c  | 6 +++---
 3 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/isdn/hisax/hfc_pci.c b/drivers/isdn/hisax/hfc_pci.c
index 8e5b03161b2f..7bcd104e9dfe 100644
--- a/drivers/isdn/hisax/hfc_pci.c
+++ b/drivers/isdn/hisax/hfc_pci.c
@@ -128,7 +128,7 @@ reset_hfcpci(struct IsdnCardState *cs)
 	Write_hfc(cs, HFCPCI_INT_M1, cs->hw.hfcpci.int_m1);
 
 	/* Clear already pending ints */
-	if (Read_hfc(cs, HFCPCI_INT_S1));
+	Read_hfc(cs, HFCPCI_INT_S1);
 
 	Write_hfc(cs, HFCPCI_STATES, HFCPCI_LOAD_STATE | 2);	/* HFC ST 2 */
 	udelay(10);
@@ -158,7 +158,7 @@ reset_hfcpci(struct IsdnCardState *cs)
 	/* Finally enable IRQ output */
 	cs->hw.hfcpci.int_m2 = HFCPCI_IRQ_ENABLE;
 	Write_hfc(cs, HFCPCI_INT_M2, cs->hw.hfcpci.int_m2);
-	if (Read_hfc(cs, HFCPCI_INT_S1));
+	Read_hfc(cs, HFCPCI_INT_S1);
 }
 
 /***************************************************/
@@ -1537,7 +1537,7 @@ hfcpci_bh(struct work_struct *work)
 					cs->hw.hfcpci.int_m1 &= ~HFCPCI_INTS_TIMER;
 					Write_hfc(cs, HFCPCI_INT_M1, cs->hw.hfcpci.int_m1);
 					/* Clear already pending ints */
-					if (Read_hfc(cs, HFCPCI_INT_S1));
+					Read_hfc(cs, HFCPCI_INT_S1);
 					Write_hfc(cs, HFCPCI_STATES, 4 | HFCPCI_LOAD_STATE);
 					udelay(10);
 					Write_hfc(cs, HFCPCI_STATES, 4);
diff --git a/drivers/isdn/hisax/hfc_pci.h b/drivers/isdn/hisax/hfc_pci.h
index 4e58700a3e61..4c3b3ba35726 100644
--- a/drivers/isdn/hisax/hfc_pci.h
+++ b/drivers/isdn/hisax/hfc_pci.h
@@ -228,8 +228,8 @@ typedef union {
 } fifo_area;
 
 
-#define Write_hfc(a, b, c) (*(((u_char *)a->hw.hfcpci.pci_io) + b) = c)
-#define Read_hfc(a, b) (*(((u_char *)a->hw.hfcpci.pci_io) + b))
+#define Write_hfc(a, b, c) (writeb(c, (a->hw.hfcpci.pci_io) + b))
+#define Read_hfc(a, b) (readb((a->hw.hfcpci.pci_io) + b))
 
 extern void main_irq_hcpci(struct BCState *bcs);
 extern void releasehfcpci(struct IsdnCardState *cs);
diff --git a/drivers/isdn/hisax/hfc_sx.c b/drivers/isdn/hisax/hfc_sx.c
index 4d3b4b2f2612..12af628d9b2c 100644
--- a/drivers/isdn/hisax/hfc_sx.c
+++ b/drivers/isdn/hisax/hfc_sx.c
@@ -381,7 +381,7 @@ reset_hfcsx(struct IsdnCardState *cs)
 	Write_hfc(cs, HFCSX_INT_M1, cs->hw.hfcsx.int_m1);
 
 	/* Clear already pending ints */
-	if (Read_hfc(cs, HFCSX_INT_S1));
+	Read_hfc(cs, HFCSX_INT_S1);
 
 	Write_hfc(cs, HFCSX_STATES, HFCSX_LOAD_STATE | 2);	/* HFC ST 2 */
 	udelay(10);
@@ -411,7 +411,7 @@ reset_hfcsx(struct IsdnCardState *cs)
 	/* Finally enable IRQ output */
 	cs->hw.hfcsx.int_m2 = HFCSX_IRQ_ENABLE;
 	Write_hfc(cs, HFCSX_INT_M2, cs->hw.hfcsx.int_m2);
-	if (Read_hfc(cs, HFCSX_INT_S2));
+	Read_hfc(cs, HFCSX_INT_S2);
 }
 
 /***************************************************/
@@ -1288,7 +1288,7 @@ hfcsx_bh(struct work_struct *work)
 					cs->hw.hfcsx.int_m1 &= ~HFCSX_INTS_TIMER;
 					Write_hfc(cs, HFCSX_INT_M1, cs->hw.hfcsx.int_m1);
 					/* Clear already pending ints */
-					if (Read_hfc(cs, HFCSX_INT_S1));
+					Read_hfc(cs, HFCSX_INT_S1);
 
 					Write_hfc(cs, HFCSX_STATES, 4 | HFCSX_LOAD_STATE);
 					udelay(10);
-- 
2.19.1