[PATCH v4 0/2] dc395x: fix compiler warnings and improve formatting of the macros

[PATCH v4 0/2] dc395x: fix compiler warnings and improve formatting of the macros

[Xinhui Yang]

This series of patches clears the compiler warnings for the dc395x
driver.

The first patch introduces a new macro that casts the value returned by
a read operation to void, since some values returned by some specific
read operations (which just simply clears the FIFO buffer or resets the
interrupt status) can be ignored. Creating a new macro that casts the
return value to void to fix the warning.

During the fix, checkpatch.pl complained about missing white space
between macro arguments and missing parentheses around complex
expressions. To align with the changes in the first patch, the
formatting of macros above and below the introduced macro are also
fixed.

Since in Patch v2 [2] Bart pointed out that such change can't be made
to the stable tree, the patch is split to two parts.

---
Changes since v3 [1]:
- Undo some mistakes in the patch 2 of the patch v2 where extra
  parentheses are added around function calls.
- Remove the unnecessary casts from the inb(), inw() and inl() calls,
  so that extra parentheses are no longer required. They are now returns
  the type it was being casted to, as James pointed out.

Changes since v2 [2]:
- Split the patch into two parts, the first one fixes the warning, and
  the second one improves the formatting of the surrounding macros.
- Make the description of the formatting changes more clear.

Changes since v1 [3]:
- Add Cc: tag to include this patch to the stable tree.
- Add additional description about the formatting changes.

[1]: https://lore.kernel.org/linux-scsi/20250923125226.1883391-1-cyan@cyano.uk/
[2]: https://lore.kernel.org/linux-scsi/20250922152609.827311-1-cyan@cyano.uk/
[3]: https://lore.kernel.org/linux-scsi/20250922143619.824129-1-cyan@cyano.uk/

---
Xinhui Yang (2):
  scsi: dc395x: correctly discard the return value in certain reads
  scsi: dc395x: improve code formatting for the macros

 drivers/scsi/dc395x.c | 34 ++++++++++++++++++++--------------
 1 file changed, 20 insertions(+), 14 deletions(-)

---
Xinhui Yang (2):
  scsi: dc395x: correctly discard the return value in certain reads
  scsi: dc395x: improve code formatting for the macros

 drivers/scsi/dc395x.c | 34 ++++++++++++++++++++--------------
 1 file changed, 20 insertions(+), 14 deletions(-)

-- 
2.51.0

[PATCH v4 1/2] scsi: dc395x: correctly discard the return value in certain reads

[Xinhui Yang]

There are certain read operations performed in this code which doesn't
really need its return value. Those read operations either clears the
FIFO buffer, or clears the interruption status. However, unused read
triggers compiler warnings. With CONFIG_WERROR on, these warnings get
converted into errors:

drivers/scsi/dc395x.c: In function ‘__dc395x_eh_bus_reset’:
drivers/scsi/dc395x.c:97:49: error: value computed is not used [-Werror=unused-value]
   97 | #define DC395x_read8(acb,address)               (u8)(inb(acb->io_port_base + (address)))
      |                                                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/scsi/dc395x.c:1003:9: note: in expansion of macro ‘DC395x_read8’
 1003 |         DC395x_read8(acb, TRM_S1040_SCSI_INTSTATUS);
      |         ^~~~~~~~~~~~
drivers/scsi/dc395x.c: In function ‘data_io_transfer’:
drivers/scsi/dc395x.c:97:49: error: value computed is not used [-Werror=unused-value]
   97 | #define DC395x_read8(acb,address)               (u8)(inb(acb->io_port_base + (address)))
      |                                                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/scsi/dc395x.c:2032:33: note: in expansion of macro ‘DC395x_read8’
 2032 |                                 DC395x_read8(acb, TRM_S1040_SCSI_FIFO);

Create a new macro DC395x_peek8() to deliberately cast the return value
to void, which tells the compiler we really don't need the return value
of such read operations.

Cc: stable@vger.kernel.org
Signed-off-by: Xinhui Yang <cyan@cyano.uk>
---
 drivers/scsi/dc395x.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/drivers/scsi/dc395x.c b/drivers/scsi/dc395x.c
index 386c8359e1cc..aed4f21e8143 100644
--- a/drivers/scsi/dc395x.c
+++ b/drivers/scsi/dc395x.c
@@ -94,6 +94,12 @@
 #define DC395x_LOCK_IO(dev,flags)		spin_lock_irqsave(((struct Scsi_Host *)dev)->host_lock, flags)
 #define DC395x_UNLOCK_IO(dev,flags)		spin_unlock_irqrestore(((struct Scsi_Host *)dev)->host_lock, flags)
 
+/*
+ * read operations that may trigger side effects in the hardware,
+ * but the value can or should be discarded.
+ */
+#define DC395x_peek8(acb, address)		((void)(inb(acb->io_port_base + (address))))
+/* normal read write operations goes here. */
 #define DC395x_read8(acb,address)		(u8)(inb(acb->io_port_base + (address)))
 #define DC395x_read16(acb,address)		(u16)(inw(acb->io_port_base + (address)))
 #define DC395x_read32(acb,address)		(u32)(inl(acb->io_port_base + (address)))
@@ -1000,7 +1006,7 @@ static int __dc395x_eh_bus_reset(struct scsi_cmnd *cmd)
 	DC395x_write8(acb, TRM_S1040_DMA_CONTROL, CLRXFIFO);
 	clear_fifo(acb, "eh_bus_reset");
 	/* Delete pending IRQ */
-	DC395x_read8(acb, TRM_S1040_SCSI_INTSTATUS);
+	DC395x_peek8(acb, TRM_S1040_SCSI_INTSTATUS);
 	set_basic_config(acb);
 
 	reset_dev_param(acb);
@@ -2029,8 +2035,8 @@ static void data_io_transfer(struct AdapterCtlBlk *acb,
 			DC395x_write8(acb, TRM_S1040_SCSI_CONFIG2,
 				      CFG2_WIDEFIFO);
 			if (io_dir & DMACMD_DIR) {
-				DC395x_read8(acb, TRM_S1040_SCSI_FIFO);
-				DC395x_read8(acb, TRM_S1040_SCSI_FIFO);
+				DC395x_peek8(acb, TRM_S1040_SCSI_FIFO);
+				DC395x_peek8(acb, TRM_S1040_SCSI_FIFO);
 			} else {
 				/* Danger, Robinson: If you find KGs
 				 * scattered over the wide disk, the driver
@@ -2044,7 +2050,7 @@ static void data_io_transfer(struct AdapterCtlBlk *acb,
 			/* Danger, Robinson: If you find a collection of Ks on your disk
 			 * something broke :-( */
 			if (io_dir & DMACMD_DIR)
-				DC395x_read8(acb, TRM_S1040_SCSI_FIFO);
+				DC395x_peek8(acb, TRM_S1040_SCSI_FIFO);
 			else
 				DC395x_write8(acb, TRM_S1040_SCSI_FIFO, 'K');
 		}
@@ -2892,7 +2898,7 @@ static void set_basic_config(struct AdapterCtlBlk *acb)
 	    DMA_FIFO_HALF_HALF | DMA_ENHANCE /*| DMA_MEM_MULTI_READ */ ;
 	DC395x_write16(acb, TRM_S1040_DMA_CONFIG, wval);
 	/* Clear pending interrupt status */
-	DC395x_read8(acb, TRM_S1040_SCSI_INTSTATUS);
+	DC395x_peek8(acb, TRM_S1040_SCSI_INTSTATUS);
 	/* Enable SCSI interrupt    */
 	DC395x_write8(acb, TRM_S1040_SCSI_INTEN, 0x7F);
 	DC395x_write8(acb, TRM_S1040_DMA_INTEN, EN_SCSIINTR | EN_DMAXFERERROR
@@ -3799,7 +3805,7 @@ static void adapter_uninit_chip(struct AdapterCtlBlk *acb)
 		reset_scsi_bus(acb);
 
 	/* clear any pending interrupt state */
-	DC395x_read8(acb, TRM_S1040_SCSI_INTSTATUS);
+	DC395x_peek8(acb, TRM_S1040_SCSI_INTSTATUS);
 }
 
 
-- 
2.51.0

[PATCH v4 2/2] scsi: dc395x: improve code formatting for the macros

[Xinhui Yang]

The DC395x_* macros does not have white spaces between their arguments,
and checkpatch.pl throws an error for each change in the macros. Adding
white spaces between the arguments to fix the formatting.

Also, there are no surrounding parentheses in the expressions for the
read macros, since these casts makes the expression a compound, which
checkpatch.pl also complained about.
Removing the type casts of the inb(), inw() and inl() calls. They now
returns the expected type without explicit casting.

This patch does only formatting improvements to make the macro
definitions align with the previous patch.

[1]: https://lore.kernel.org/linux-scsi/1ae97d061da14b0d85c0938c3000ed57ccd39382.camel@HansenPartnership.com/

Signed-off-by: Xinhui Yang <cyan@cyano.uk>
---
 drivers/scsi/dc395x.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/scsi/dc395x.c b/drivers/scsi/dc395x.c
index aed4f21e8143..1fb954180269 100644
--- a/drivers/scsi/dc395x.c
+++ b/drivers/scsi/dc395x.c
@@ -91,8 +91,8 @@
 #endif
 
 
-#define DC395x_LOCK_IO(dev,flags)		spin_lock_irqsave(((struct Scsi_Host *)dev)->host_lock, flags)
-#define DC395x_UNLOCK_IO(dev,flags)		spin_unlock_irqrestore(((struct Scsi_Host *)dev)->host_lock, flags)
+#define DC395x_LOCK_IO(dev, flags)		spin_lock_irqsave(((struct Scsi_Host *)dev)->host_lock, flags)
+#define DC395x_UNLOCK_IO(dev, flags)		spin_unlock_irqrestore(((struct Scsi_Host *)dev)->host_lock, flags)
 
 /*
  * read operations that may trigger side effects in the hardware,
@@ -100,12 +100,12 @@
  */
 #define DC395x_peek8(acb, address)		((void)(inb(acb->io_port_base + (address))))
 /* normal read write operations goes here. */
-#define DC395x_read8(acb,address)		(u8)(inb(acb->io_port_base + (address)))
-#define DC395x_read16(acb,address)		(u16)(inw(acb->io_port_base + (address)))
-#define DC395x_read32(acb,address)		(u32)(inl(acb->io_port_base + (address)))
-#define DC395x_write8(acb,address,value)	outb((value), acb->io_port_base + (address))
-#define DC395x_write16(acb,address,value)	outw((value), acb->io_port_base + (address))
-#define DC395x_write32(acb,address,value)	outl((value), acb->io_port_base + (address))
+#define DC395x_read8(acb, address)		inb(acb->io_port_base + (address))
+#define DC395x_read16(acb, address)		inw(acb->io_port_base + (address))
+#define DC395x_read32(acb, address)		inl(acb->io_port_base + (address))
+#define DC395x_write8(acb, address, value)	outb((value), acb->io_port_base + (address))
+#define DC395x_write16(acb, address, value)	outw((value), acb->io_port_base + (address))
+#define DC395x_write32(acb, address, value)	outl((value), acb->io_port_base + (address))
 
 #define TAG_NONE 255
 
-- 
2.51.0

Re: [PATCH v4 2/2] scsi: dc395x: improve code formatting for the macros

[kernel test robot]

Hi,

Thanks for your patch.

FYI: kernel test robot notices the stable kernel rule is not satisfied.

The check is based on https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html#option-1

Rule: add the tag "Cc: stable@vger.kernel.org" in the sign-off area to have the patch automatically included in the stable tree.
Subject: [PATCH v4 2/2] scsi: dc395x: improve code formatting for the macros
Link: https://lore.kernel.org/stable/20250924055628.1929177-3-cyan%40cyano.uk

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https://github.com/intel/lkp-tests/wiki