Re: [PATCH] staging/hv/osd: don't reimplement ALIGN macro

["Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>]

On Tue, Jan 18, 2011 at 09:37:15PM -0800, Greg KH wrote:
> On Tue, Jan 18, 2011 at 04:39:11PM +0100, Uwe Kleine-König wrote:
> > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
> > ---
> >  drivers/staging/hv/osd.h |    5 ++---
> >  1 files changed, 2 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/staging/hv/osd.h b/drivers/staging/hv/osd.h
> > index ce064e8..61ae54c 100644
> > --- a/drivers/staging/hv/osd.h
> > +++ b/drivers/staging/hv/osd.h
> > @@ -28,10 +28,9 @@
> >  #include <linux/workqueue.h>
> >  
> >  /* Defines */
> > -#define ALIGN_UP(value, align)	(((value) & (align-1)) ?		\
> > -				 (((value) + (align-1)) & ~(align-1)) :	\
> > -				 (value))
> > +#define ALIGN_UP(value, align)		ALIGN((value), (align))
> 
> How about dropping ALIGN_UP entirely and just using the built-in ALIGN()
> macro instead?
Can do.

> >  #define ALIGN_DOWN(value, align)	((value) & ~(align-1))
> 
> Any chance to get rid of this as well with the ALIGN() macro, or is that
> really not possible?
it would be

	#define ALIGN_DOWN(value, align) ALIGN((value) - (align) + 1, (align))

I think, but as it's only used once it might be easier to just use ALIGN
there, too.

BTW, it's used as follows:

	#define NUM_PAGES_SPANNED(addr, len)    ((ALIGN(addr+len, PAGE_SIZE) - \
						 ALIGN_DOWN(addr, PAGE_SIZE)) >>  \
						 PAGE_SHIFT)

I wonder if there is already a function yielding this value?
Wouldn't

	((addr + len) >> PAGE_SHIFT) - (addr >> PAGE_SHIFT) + 1

just work?  (At least if len > 0, but for other values the original
macro was wrong, too.  The maybe more correct

	abs(((addr + len) >> PAGE_SHIFT) - (addr >> PAGE_SHIFT)) + (len > 0)

is probably just overkill.)

Patch below.

Best regards
Uwe

-------------->8------------------
staging/hv/osd: don't reimplement ALIGN macro

From: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

The ALIGN_DOWN macro was only used in NUM_PAGES_SPANNED.  So make the
latter easier and get rid of the former.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
---
 drivers/staging/hv/blkvsc.c      |    2 +-
 drivers/staging/hv/channel.c     |    6 +++---
 drivers/staging/hv/hv.c          |    4 ++--
 drivers/staging/hv/osd.h         |   10 +++-------
 drivers/staging/hv/storvsc.c     |    6 +++---
 drivers/staging/hv/storvsc_drv.c |    4 ++--
 6 files changed, 14 insertions(+), 18 deletions(-)

diff --git a/drivers/staging/hv/blkvsc.c b/drivers/staging/hv/blkvsc.c
index bc16d91..11a2523 100644
--- a/drivers/staging/hv/blkvsc.c
+++ b/drivers/staging/hv/blkvsc.c
@@ -85,7 +85,7 @@ int blk_vsc_initialize(struct hv_driver *driver)
 	 */
 	stor_driver->max_outstanding_req_per_channel =
 		((stor_driver->ring_buffer_size - PAGE_SIZE) /
-		  ALIGN_UP(MAX_MULTIPAGE_BUFFER_PACKET +
+		  ALIGN(MAX_MULTIPAGE_BUFFER_PACKET +
 			   sizeof(struct vstor_packet) + sizeof(u64),
 			   sizeof(u64)));
 
diff --git a/drivers/staging/hv/channel.c b/drivers/staging/hv/channel.c
index 45a627d..69e7856 100644
--- a/drivers/staging/hv/channel.c
+++ b/drivers/staging/hv/channel.c
@@ -726,7 +726,7 @@ int vmbus_sendpacket(struct vmbus_channel *channel, const void *buffer,
 {
 	struct vmpacket_descriptor desc;
 	u32 packetlen = sizeof(struct vmpacket_descriptor) + bufferlen;
-	u32 packetlen_aligned = ALIGN_UP(packetlen, sizeof(u64));
+	u32 packetlen_aligned = ALIGN(packetlen, sizeof(u64));
 	struct scatterlist bufferlist[3];
 	u64 aligned_data = 0;
 	int ret;
@@ -793,7 +793,7 @@ int vmbus_sendpacket_pagebuffer(struct vmbus_channel *channel,
 			  ((MAX_PAGE_BUFFER_COUNT - pagecount) *
 			  sizeof(struct hv_page_buffer));
 	packetlen = descsize + bufferlen;
-	packetlen_aligned = ALIGN_UP(packetlen, sizeof(u64));
+	packetlen_aligned = ALIGN(packetlen, sizeof(u64));
 
 	/* ASSERT((packetLenAligned - packetLen) < sizeof(u64)); */
 
@@ -862,7 +862,7 @@ int vmbus_sendpacket_multipagebuffer(struct vmbus_channel *channel,
 			  ((MAX_MULTIPAGE_BUFFER_COUNT - pfncount) *
 			  sizeof(u64));
 	packetlen = descsize + bufferlen;
-	packetlen_aligned = ALIGN_UP(packetlen, sizeof(u64));
+	packetlen_aligned = ALIGN(packetlen, sizeof(u64));
 
 	/* ASSERT((packetLenAligned - packetLen) < sizeof(u64)); */
 
diff --git a/drivers/staging/hv/hv.c b/drivers/staging/hv/hv.c
index a34d713..021acba 100644
--- a/drivers/staging/hv/hv.c
+++ b/drivers/staging/hv/hv.c
@@ -267,7 +267,7 @@ int hv_init(void)
 
 	hv_context.signal_event_param =
 		(struct hv_input_signal_event *)
-			(ALIGN_UP((unsigned long)
+			(ALIGN((unsigned long)
 				  hv_context.signal_event_buffer,
 				  HV_HYPERCALL_PARAM_ALIGN));
 	hv_context.signal_event_param->connectionid.asu32 = 0;
@@ -338,7 +338,7 @@ u16 hv_post_message(union hv_connection_id connection_id,
 		return -1;
 
 	aligned_msg = (struct hv_input_post_message *)
-			(ALIGN_UP(addr, HV_HYPERCALL_PARAM_ALIGN));
+			(ALIGN(addr, HV_HYPERCALL_PARAM_ALIGN));
 
 	aligned_msg->connectionid = connection_id;
 	aligned_msg->message_type = message_type;
diff --git a/drivers/staging/hv/osd.h b/drivers/staging/hv/osd.h
index 870ef07..85ccb29 100644
--- a/drivers/staging/hv/osd.h
+++ b/drivers/staging/hv/osd.h
@@ -25,16 +25,12 @@
 #ifndef _OSD_H_
 #define _OSD_H_
 
+#include <linux/kernel.h>
 #include <linux/workqueue.h>
 
 /* Defines */
-#define ALIGN_UP(value, align)	(((value) & (align-1)) ?		\
-				 (((value) + (align-1)) & ~(align-1)) :	\
-				 (value))
-#define ALIGN_DOWN(value, align)	((value) & ~(align-1))
-#define NUM_PAGES_SPANNED(addr, len)	((ALIGN_UP(addr+len, PAGE_SIZE) - \
-					 ALIGN_DOWN(addr, PAGE_SIZE)) >>  \
-					 PAGE_SHIFT)
+#define NUM_PAGES_SPANNED(addr, len)	(((addr + len) >> PAGE_SHIFT) -	\
+					(addr >> PAGE_SHIFT) + 1)
 
 #define LOWORD(dw)	((unsigned short)(dw))
 #define HIWORD(dw)	((unsigned short)(((unsigned int) (dw) >> 16) & 0xFFFF))
diff --git a/drivers/staging/hv/storvsc.c b/drivers/staging/hv/storvsc.c
index 9295113..5680fb0 100644
--- a/drivers/staging/hv/storvsc.c
+++ b/drivers/staging/hv/storvsc.c
@@ -437,7 +437,7 @@ static void stor_vsc_on_channel_callback(void *context)
 	struct storvsc_device *stor_device;
 	u32 bytes_recvd;
 	u64 request_id;
-	unsigned char packet[ALIGN_UP(sizeof(struct vstor_packet), 8)];
+	unsigned char packet[ALIGN(sizeof(struct vstor_packet), 8)];
 	struct storvsc_request_extension *request;
 	int ret;
 
@@ -452,7 +452,7 @@ static void stor_vsc_on_channel_callback(void *context)
 
 	do {
 		ret = vmbus_recvpacket(device->channel, packet,
-				       ALIGN_UP(sizeof(struct vstor_packet), 8),
+				       ALIGN(sizeof(struct vstor_packet), 8),
 				       &bytes_recvd, &request_id);
 		if (ret == 0 && bytes_recvd > 0) {
 			DPRINT_DBG(STORVSC, "receive %d bytes - tid %llx",
@@ -802,7 +802,7 @@ int stor_vsc_initialize(struct hv_driver *driver)
 	 */
 	stor_driver->max_outstanding_req_per_channel =
 		((stor_driver->ring_buffer_size - PAGE_SIZE) /
-		  ALIGN_UP(MAX_MULTIPAGE_BUFFER_PACKET +
+		  ALIGN(MAX_MULTIPAGE_BUFFER_PACKET +
 			   sizeof(struct vstor_packet) + sizeof(u64),
 			   sizeof(u64)));
 
diff --git a/drivers/staging/hv/storvsc_drv.c b/drivers/staging/hv/storvsc_drv.c
index 17f1b34..7651ca2 100644
--- a/drivers/staging/hv/storvsc_drv.c
+++ b/drivers/staging/hv/storvsc_drv.c
@@ -434,7 +434,7 @@ static struct scatterlist *create_bounce_buffer(struct scatterlist *sgl,
 	struct scatterlist *bounce_sgl;
 	struct page *page_buf;
 
-	num_pages = ALIGN_UP(len, PAGE_SIZE) >> PAGE_SHIFT;
+	num_pages = ALIGN(len, PAGE_SIZE) >> PAGE_SHIFT;
 
 	bounce_sgl = kcalloc(num_pages, sizeof(struct scatterlist), GFP_ATOMIC);
 	if (!bounce_sgl)
@@ -720,7 +720,7 @@ static int storvsc_queuecommand_lck(struct scsi_cmnd *scmnd,
 			}
 
 			cmd_request->bounce_sgl_count =
-				ALIGN_UP(scsi_bufflen(scmnd), PAGE_SIZE) >>
+				ALIGN(scsi_bufflen(scmnd), PAGE_SIZE) >>
 					PAGE_SHIFT;
 
 			/*
-- 
1.7.2.3

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |