[U-Boot] [PATCH v6 0/2] common: usb_storage : Implement logic to calculate optimal

[U-Boot] [PATCH v6 0/2] common: usb_storage : Implement logic to calculate optimal

[Rajesh Bhagat]

Performs code cleanup by making common function for usb_stor_read/write
and implements the logic to calculate the optimal usb maximum trasfer blocks
instead of sending USB_MAX_XFER_BLK blocks which is 65535 and 20 in case
of EHCI and other USB protocols respectively.

Rajesh Bhagat (2):
  common: usb_storage: Make common function for    
    usb_stor_read/usb_stor_write
  common: usb_storage : Implement logic to calculate optimal usb maximum
    trasfer blocks

 common/usb_storage.c | 213 +++++++++++++++++++++++----------------------------
 include/usb.h        |   1 +
 2 files changed, 98 insertions(+), 116 deletions(-)

-- 
2.6.2.198.g614a2ac

[U-Boot] [PATCH v6 1/2] common: usb_storage: Make common function for usb_stor_read/usb_stor_write

[Rajesh Bhagat]

Performs code cleanup by making common function for usb_stor_read/
usb_stor_write. Currently only difference in these fucntions is call
to usb_read_10/usb_write_10 scsi commands.

Signed-off-by: Rajesh Bhagat <rajesh.bhagat@nxp.com>
---
Changes in v6:
 - Removes USB_STOR_OP_TYPE macro and adds __func__ in debug prints
 - Unifies usb_read_10/usb_write_10 functions to usb_read_write_10

Changes in v5:
 - Converts USB_STOR_OPERATION_FUNC macro to a function
 - Corrects the multi line comment accroding to coding style
 - Renames variable to dev to remove code duplication

Changes in v4:
 - Adds code to make common function for read/write

 common/usb_storage.c | 147 +++++++++++++--------------------------------------
 1 file changed, 36 insertions(+), 111 deletions(-)

diff --git a/common/usb_storage.c b/common/usb_storage.c
index 7e6e52d..41e5aa3 100644
--- a/common/usb_storage.c
+++ b/common/usb_storage.c
@@ -1046,11 +1046,11 @@ static int usb_read_capacity(ccb *srb, struct us_data *ss)
 	return -1;
 }
 
-static int usb_read_10(ccb *srb, struct us_data *ss, unsigned long start,
-		       unsigned short blocks)
+static int usb_read_write_10(ccb *srb, struct us_data *ss, unsigned long start,
+		       unsigned short blocks, bool is_write)
 {
 	memset(&srb->cmd[0], 0, 12);
-	srb->cmd[0] = SCSI_READ10;
+	srb->cmd[0] = is_write ? SCSI_WRITE10 : SCSI_READ10;
 	srb->cmd[1] = srb->lun << 5;
 	srb->cmd[2] = ((unsigned char) (start >> 24)) & 0xff;
 	srb->cmd[3] = ((unsigned char) (start >> 16)) & 0xff;
@@ -1059,28 +1059,10 @@ static int usb_read_10(ccb *srb, struct us_data *ss, unsigned long start,
 	srb->cmd[7] = ((unsigned char) (blocks >> 8)) & 0xff;
 	srb->cmd[8] = (unsigned char) blocks & 0xff;
 	srb->cmdlen = 12;
-	debug("read10: start %lx blocks %x\n", start, blocks);
+	debug("%s: start %lx blocks %x\n", __func__, start, blocks);
 	return ss->transport(srb, ss);
 }
 
-static int usb_write_10(ccb *srb, struct us_data *ss, unsigned long start,
-			unsigned short blocks)
-{
-	memset(&srb->cmd[0], 0, 12);
-	srb->cmd[0] = SCSI_WRITE10;
-	srb->cmd[1] = srb->lun << 5;
-	srb->cmd[2] = ((unsigned char) (start >> 24)) & 0xff;
-	srb->cmd[3] = ((unsigned char) (start >> 16)) & 0xff;
-	srb->cmd[4] = ((unsigned char) (start >> 8)) & 0xff;
-	srb->cmd[5] = ((unsigned char) (start)) & 0xff;
-	srb->cmd[7] = ((unsigned char) (blocks >> 8)) & 0xff;
-	srb->cmd[8] = (unsigned char) blocks & 0xff;
-	srb->cmdlen = 12;
-	debug("write10: start %lx blocks %x\n", start, blocks);
-	return ss->transport(srb, ss);
-}
-
-
 #ifdef CONFIG_USB_BIN_FIXUP
 /*
  * Some USB storage devices queried for SCSI identification data respond with
@@ -1105,11 +1087,13 @@ static void usb_bin_fixup(struct usb_device_descriptor descriptor,
 #endif /* CONFIG_USB_BIN_FIXUP */
 
 #ifdef CONFIG_BLK
-static unsigned long usb_stor_read(struct udevice *dev, lbaint_t blknr,
-				   lbaint_t blkcnt, void *buffer)
+static unsigned long usb_stor_read_write(struct udevice *dev, lbaint_t blknr,
+					 lbaint_t blkcnt, const void *buffer,
+					 bool is_write)
 #else
-static unsigned long usb_stor_read(struct blk_desc *block_dev, lbaint_t blknr,
-				   lbaint_t blkcnt, void *buffer)
+static unsigned long usb_stor_read_write(struct blk_desc *block_dev,
+					 lbaint_t blknr, lbaint_t blkcnt,
+					 const void *buffer, bool is_write)
 #endif
 {
 	lbaint_t start, blks;
@@ -1129,9 +1113,9 @@ static unsigned long usb_stor_read(struct blk_desc *block_dev, lbaint_t blknr,
 #ifdef CONFIG_BLK
 	block_dev = dev_get_uclass_platdata(dev);
 	udev = dev_get_parent_priv(dev_get_parent(dev));
-	debug("\nusb_read: udev %d\n", block_dev->devnum);
+	debug("\n%s: udev %d\n", __func__, block_dev->devnum);
 #else
-	debug("\nusb_read: udev %d\n", block_dev->devnum);
+	debug("\n%s: udev %d\n", __func__, block_dev->devnum);
 	udev = usb_dev_desc[block_dev->devnum].priv;
 	if (!udev) {
 		debug("%s: No device\n", __func__);
@@ -1146,11 +1130,15 @@ static unsigned long usb_stor_read(struct blk_desc *block_dev, lbaint_t blknr,
 	start = blknr;
 	blks = blkcnt;
 
-	debug("\nusb_read: dev %d startblk " LBAF ", blccnt " LBAF " buffer %"
-	      PRIxPTR "\n", block_dev->devnum, start, blks, buf_addr);
+	debug("\n%s: dev %d startblk " LBAF ", blccnt " LBAF " buffer %"
+	      PRIxPTR "\n", __func__, block_dev->devnum, start, blks,
+	      buf_addr);
 
 	do {
-		/* XXX need some comment here */
+		/*
+		 * If read/write fails retry for max retry count else
+		 * return with number of blocks written successfully.
+		 */
 		retry = 2;
 		srb->pdata = (unsigned char *)buf_addr;
 		if (blks > USB_MAX_XFER_BLK)
@@ -1162,8 +1150,8 @@ retry_it:
 			usb_show_progress();
 		srb->datalen = block_dev->blksz * smallblks;
 		srb->pdata = (unsigned char *)buf_addr;
-		if (usb_read_10(srb, ss, start, smallblks)) {
-			debug("Read ERROR\n");
+		if (usb_read_write_10(srb, ss, start, smallblks, is_write)) {
+			debug("%s ERROR\n", __func__);
 			usb_request_sense(srb, ss);
 			if (retry--)
 				goto retry_it;
@@ -1176,9 +1164,9 @@ retry_it:
 	} while (blks != 0);
 	ss->flags &= ~USB_READY;
 
-	debug("usb_read: end startblk " LBAF
+	debug("%s: end startblk " LBAF
 	      ", blccnt %x buffer %" PRIxPTR "\n",
-	      start, smallblks, buf_addr);
+	      __func__, start, smallblks, buf_addr);
 
 	usb_disable_asynch(0); /* asynch transfer allowed */
 	if (blkcnt >= USB_MAX_XFER_BLK)
@@ -1186,90 +1174,27 @@ retry_it:
 	return blkcnt;
 }
 
+
 #ifdef CONFIG_BLK
-static unsigned long usb_stor_write(struct udevice *dev, lbaint_t blknr,
-				    lbaint_t blkcnt, const void *buffer)
+static unsigned long usb_stor_read(struct udevice *dev, lbaint_t blknr,
+				   lbaint_t blkcnt, void *buffer)
 #else
-static unsigned long usb_stor_write(struct blk_desc *block_dev, lbaint_t blknr,
-				    lbaint_t blkcnt, const void *buffer)
+static unsigned long usb_stor_read(struct blk_desc *dev, lbaint_t blknr,
+				   lbaint_t blkcnt, void *buffer)
 #endif
 {
-	lbaint_t start, blks;
-	uintptr_t buf_addr;
-	unsigned short smallblks;
-	struct usb_device *udev;
-	struct us_data *ss;
-	int retry;
-	ccb *srb = &usb_ccb;
-#ifdef CONFIG_BLK
-	struct blk_desc *block_dev;
-#endif
-
-	if (blkcnt == 0)
-		return 0;
+	return usb_stor_read_write(dev, blknr, blkcnt, buffer, false);
+}
 
-	/* Setup  device */
 #ifdef CONFIG_BLK
-	block_dev = dev_get_uclass_platdata(dev);
-	udev = dev_get_parent_priv(dev_get_parent(dev));
-	debug("\nusb_read: udev %d\n", block_dev->devnum);
+static unsigned long usb_stor_write(struct udevice *dev, lbaint_t blknr,
+				    lbaint_t blkcnt, const void *buffer)
 #else
-	debug("\nusb_read: udev %d\n", block_dev->devnum);
-	udev = usb_dev_desc[block_dev->devnum].priv;
-	if (!udev) {
-		debug("%s: No device\n", __func__);
-		return 0;
-	}
+static unsigned long usb_stor_write(struct blk_desc *dev, lbaint_t blknr,
+				    lbaint_t blkcnt, const void *buffer)
 #endif
-	ss = (struct us_data *)udev->privptr;
-
-	usb_disable_asynch(1); /* asynch transfer not allowed */
-
-	srb->lun = block_dev->lun;
-	buf_addr = (uintptr_t)buffer;
-	start = blknr;
-	blks = blkcnt;
-
-	debug("\nusb_write: dev %d startblk " LBAF ", blccnt " LBAF " buffer %"
-	      PRIxPTR "\n", block_dev->devnum, start, blks, buf_addr);
-
-	do {
-		/* If write fails retry for max retry count else
-		 * return with number of blocks written successfully.
-		 */
-		retry = 2;
-		srb->pdata = (unsigned char *)buf_addr;
-		if (blks > USB_MAX_XFER_BLK)
-			smallblks = USB_MAX_XFER_BLK;
-		else
-			smallblks = (unsigned short) blks;
-retry_it:
-		if (smallblks == USB_MAX_XFER_BLK)
-			usb_show_progress();
-		srb->datalen = block_dev->blksz * smallblks;
-		srb->pdata = (unsigned char *)buf_addr;
-		if (usb_write_10(srb, ss, start, smallblks)) {
-			debug("Write ERROR\n");
-			usb_request_sense(srb, ss);
-			if (retry--)
-				goto retry_it;
-			blkcnt -= blks;
-			break;
-		}
-		start += smallblks;
-		blks -= smallblks;
-		buf_addr += srb->datalen;
-	} while (blks != 0);
-	ss->flags &= ~USB_READY;
-
-	debug("usb_write: end startblk " LBAF ", blccnt %x buffer %"
-	      PRIxPTR "\n", start, smallblks, buf_addr);
-
-	usb_disable_asynch(0); /* asynch transfer allowed */
-	if (blkcnt >= USB_MAX_XFER_BLK)
-		debug("\n");
-	return blkcnt;
-
+{
+	return usb_stor_read_write(dev, blknr, blkcnt, buffer, true);
 }
 
 /* Probe to see if a new device is actually a Storage device */
-- 
2.6.2.198.g614a2ac

[U-Boot] [PATCH v6 2/2] common: usb_storage : Implement logic to calculate optimal usb maximum trasfer blocks

[Rajesh Bhagat]

Implements the logic to calculate the optimal usb maximum trasfer blocks
instead of sending USB_MAX_XFER_BLK blocks which is 65535 and 20 in case
of EHCI and other USB protocols respectively.

It defines USB_MIN_XFER_BLK/USB_MAX_XFER_BLK trasfer blocks that should
be checked for success starting from minimum to maximum, and rest of the
read/write are performed with that optimal value. It tries to increase/
decrease the blocks in follwing scenarios:

1.decrease blocks: when read/write for a particular number of blocks
fails.
2. increase blocks: when read/write for a particular number of blocks
pass and amount left to trasfer is greater than current number of
blocks.

Currently changes are done for EHCI where min = 4096 and max = 65535
is taken. And for other cases code is left unchanged by keeping min
= max = 20.

Signed-off-by: Sriram Dash <sriram.dash@nxp.com>
Signed-off-by: Rajesh Bhagat <rajesh.bhagat@nxp.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
---
Changes in v6:
 - Adds paranthesis around macro variables
 - Removes extra ternary operator from dec_cur_xfer_blks
 - Clamps the size to min(blks, USB_MAX_XFER_BLK) in inc_cur_xfer_blks

Changes in v5:
 - None

Changes in v4:
 - Adds udev paramater in dec/inc_cur_xfer_blks function and adds
   sanity check on it.
 - Changes type of pos varible to unsigned int in dec/inc_cur_xfer_blks
 - Removes usage of pos varible from usb_stor_read/write

Changes in v3:
 - Adds cur_xfer_blks in struct usb_device to retain values
 - Adds functions dec/inc_cur_xfer_blks to remove code duplication
 - Moves check from macro to calling functions

Changes in v2:
 - Removes table to store blocks and use formula (1 << (12 + n)) - 1
 - Adds logic to start from minimum, go to maximum in each read/write

 common/usb_storage.c | 66 ++++++++++++++++++++++++++++++++++++++++++++++++----
 include/usb.h        |  1 +
 2 files changed, 62 insertions(+), 5 deletions(-)

diff --git a/common/usb_storage.c b/common/usb_storage.c
index 41e5aa3..0856052 100644
--- a/common/usb_storage.c
+++ b/common/usb_storage.c
@@ -106,11 +106,16 @@ struct us_data {
  * enough free heap space left, but the SCSI READ(10) and WRITE(10) commands are
  * limited to 65535 blocks.
  */
+#define USB_MIN_XFER_BLK	4095
 #define USB_MAX_XFER_BLK	65535
 #else
+#define USB_MIN_XFER_BLK	20
 #define USB_MAX_XFER_BLK	20
 #endif
 
+#define GET_CUR_XFER_BLKS(blks)	(LOG2(((blks) + 1) / (USB_MIN_XFER_BLK + 1)))
+#define CALC_CUR_XFER_BLKS(pos)	((1 << (12 + (pos))) - 1)
+
 #ifndef CONFIG_BLK
 static struct us_data usb_stor[USB_MAX_STOR_DEV];
 #endif
@@ -141,6 +146,44 @@ static void usb_show_progress(void)
 	debug(".");
 }
 
+static int dec_cur_xfer_blks(struct usb_device *udev)
+{
+	/* decrease the cur_xfer_blks */
+	unsigned int pos;
+	unsigned short size;
+
+	if (!udev)
+		return -EINVAL;
+
+	pos = GET_CUR_XFER_BLKS(udev->cur_xfer_blks);
+	size  = CALC_CUR_XFER_BLKS(pos - 1);
+
+	if (size < USB_MIN_XFER_BLK)
+		return -EINVAL;
+
+	udev->cur_xfer_blks = size;
+	return 0;
+}
+
+static int inc_cur_xfer_blks(struct usb_device *udev, lbaint_t blks)
+{
+	/* try to increase the cur_xfer_blks */
+	unsigned int pos;
+	unsigned short size;
+
+	if (!udev)
+		return -EINVAL;
+
+	pos = GET_CUR_XFER_BLKS(udev->cur_xfer_blks);
+	size = CALC_CUR_XFER_BLKS(pos + 1);
+
+	if (size > min(blks, (lbaint_t)USB_MAX_XFER_BLK))
+		return -EINVAL;
+
+	udev->cur_xfer_blks = size;
+	return 0;
+}
+
 /*******************************************************************************
  * show info on storage devices; 'usb start/init' must be invoked earlier
  * as we only retrieve structures populated during devices initialization
@@ -1102,6 +1145,7 @@ static unsigned long usb_stor_read_write(struct blk_desc *block_dev,
 	struct usb_device *udev;
 	struct us_data *ss;
 	int retry;
+	bool retry_flag = false;
 	ccb *srb = &usb_ccb;
 #ifdef CONFIG_BLK
 	struct blk_desc *block_dev;
@@ -1141,26 +1185,35 @@ static unsigned long usb_stor_read_write(struct blk_desc *block_dev,
 		 */
 		retry = 2;
 		srb->pdata = (unsigned char *)buf_addr;
-		if (blks > USB_MAX_XFER_BLK)
-			smallblks = USB_MAX_XFER_BLK;
+		if (blks > udev->cur_xfer_blks)
+			smallblks = udev->cur_xfer_blks;
 		else
 			smallblks = (unsigned short) blks;
 retry_it:
-		if (smallblks == USB_MAX_XFER_BLK)
+		debug("%s: retry #%d, cur_xfer_blks %hu, smallblks %hu\n",
+		      __func__, retry, udev->cur_xfer_blks, smallblks);
+		if (smallblks == udev->cur_xfer_blks)
 			usb_show_progress();
 		srb->datalen = block_dev->blksz * smallblks;
 		srb->pdata = (unsigned char *)buf_addr;
 		if (usb_read_write_10(srb, ss, start, smallblks, is_write)) {
 			debug("%s ERROR\n", __func__);
 			usb_request_sense(srb, ss);
-			if (retry--)
+			if (retry--) {
+				if (!dec_cur_xfer_blks(udev))
+					smallblks = udev->cur_xfer_blks;
+				retry_flag = true;
 				goto retry_it;
+			}
 			blkcnt -= blks;
 			break;
 		}
 		start += smallblks;
 		blks -= smallblks;
 		buf_addr += srb->datalen;
+
+		if (!retry_flag && !inc_cur_xfer_blks(udev, blks))
+			smallblks = udev->cur_xfer_blks;
 	} while (blks != 0);
 	ss->flags &= ~USB_READY;
 
@@ -1169,7 +1222,7 @@ retry_it:
 	      __func__, start, smallblks, buf_addr);
 
 	usb_disable_asynch(0); /* asynch transfer allowed */
-	if (blkcnt >= USB_MAX_XFER_BLK)
+	if (blkcnt >= udev->cur_xfer_blks)
 		debug("\n");
 	return blkcnt;
 }
@@ -1256,6 +1309,9 @@ int usb_storage_probe(struct usb_device *dev, unsigned int ifnum,
 		break;
 	}
 
+	/* Initialize the current transfer blocks to minimum value */
+	dev->cur_xfer_blks = USB_MIN_XFER_BLK;
+
 	/*
 	 * We are expecting a minimum of 2 endpoints - in and out (bulk).
 	 * An optional interrupt is OK (necessary for CBI protocol).
diff --git a/include/usb.h b/include/usb.h
index 02a0ccd..b815816 100644
--- a/include/usb.h
+++ b/include/usb.h
@@ -153,6 +153,7 @@ struct usb_device {
 	struct udevice *dev;		/* Pointer to associated device */
 	struct udevice *controller_dev;	/* Pointer to associated controller */
 #endif
+	unsigned short cur_xfer_blks;   /* Current maximum transfer blocks */
 };
 
 struct int_queue;
-- 
2.6.2.198.g614a2ac

[U-Boot] [PATCH v6 1/2] common: usb_storage: Make common function for usb_stor_read/usb_stor_write

[Marek Vasut]

On 06/15/2016 09:00 AM, Rajesh Bhagat wrote:
> Performs code cleanup by making common function for usb_stor_read/
> usb_stor_write. Currently only difference in these fucntions is call
> to usb_read_10/usb_write_10 scsi commands.
> 
> Signed-off-by: Rajesh Bhagat <rajesh.bhagat@nxp.com>
> ---
> Changes in v6:
>  - Removes USB_STOR_OP_TYPE macro and adds __func__ in debug prints
>  - Unifies usb_read_10/usb_write_10 functions to usb_read_write_10
> 
> Changes in v5:
>  - Converts USB_STOR_OPERATION_FUNC macro to a function
>  - Corrects the multi line comment accroding to coding style
>  - Renames variable to dev to remove code duplication
> 
> Changes in v4:
>  - Adds code to make common function for read/write
> 
>  common/usb_storage.c | 147 +++++++++++++--------------------------------------
>  1 file changed, 36 insertions(+), 111 deletions(-)
> 
> diff --git a/common/usb_storage.c b/common/usb_storage.c
> index 7e6e52d..41e5aa3 100644
> --- a/common/usb_storage.c
> +++ b/common/usb_storage.c
> @@ -1046,11 +1046,11 @@ static int usb_read_capacity(ccb *srb, struct us_data *ss)
>  	return -1;
>  }
>  
> -static int usb_read_10(ccb *srb, struct us_data *ss, unsigned long start,
> -		       unsigned short blocks)
> +static int usb_read_write_10(ccb *srb, struct us_data *ss, unsigned long start,
> +		       unsigned short blocks, bool is_write)
>  {
>  	memset(&srb->cmd[0], 0, 12);
> -	srb->cmd[0] = SCSI_READ10;
> +	srb->cmd[0] = is_write ? SCSI_WRITE10 : SCSI_READ10;
>  	srb->cmd[1] = srb->lun << 5;
>  	srb->cmd[2] = ((unsigned char) (start >> 24)) & 0xff;
>  	srb->cmd[3] = ((unsigned char) (start >> 16)) & 0xff;
> @@ -1059,28 +1059,10 @@ static int usb_read_10(ccb *srb, struct us_data *ss, unsigned long start,
>  	srb->cmd[7] = ((unsigned char) (blocks >> 8)) & 0xff;
>  	srb->cmd[8] = (unsigned char) blocks & 0xff;
>  	srb->cmdlen = 12;
> -	debug("read10: start %lx blocks %x\n", start, blocks);
> +	debug("%s: start %lx blocks %x\n", __func__, start, blocks);
>  	return ss->transport(srb, ss);
>  }
>  
> -static int usb_write_10(ccb *srb, struct us_data *ss, unsigned long start,
> -			unsigned short blocks)
> -{
> -	memset(&srb->cmd[0], 0, 12);
> -	srb->cmd[0] = SCSI_WRITE10;
> -	srb->cmd[1] = srb->lun << 5;
> -	srb->cmd[2] = ((unsigned char) (start >> 24)) & 0xff;
> -	srb->cmd[3] = ((unsigned char) (start >> 16)) & 0xff;
> -	srb->cmd[4] = ((unsigned char) (start >> 8)) & 0xff;
> -	srb->cmd[5] = ((unsigned char) (start)) & 0xff;
> -	srb->cmd[7] = ((unsigned char) (blocks >> 8)) & 0xff;
> -	srb->cmd[8] = (unsigned char) blocks & 0xff;
> -	srb->cmdlen = 12;
> -	debug("write10: start %lx blocks %x\n", start, blocks);
> -	return ss->transport(srb, ss);
> -}
> -

This stuff should be in a separate patch, otherwise it's not bisectable.
Looks pretty OK otherwise.

[...]

-- 
Best regards,
Marek Vasut

[U-Boot] [PATCH v6 1/2] common: usb_storage: Make common function for usb_stor_read/usb_stor_write

[Rajesh Bhagat]

> -----Original Message-----
> From: Marek Vasut [mailto:marex at denx.de]
> Sent: Thursday, June 16, 2016 3:33 AM
> To: Rajesh Bhagat <rajesh.bhagat@nxp.com>; u-boot at lists.denx.de
> Cc: sjg at chromium.org; york sun <york.sun@nxp.com>; Sriram Dash
> <sriram.dash@nxp.com>
> Subject: Re: [PATCH v6 1/2] common: usb_storage: Make common function for
> usb_stor_read/usb_stor_write
> 
> On 06/15/2016 09:00 AM, Rajesh Bhagat wrote:
> > Performs code cleanup by making common function for usb_stor_read/
> > usb_stor_write. Currently only difference in these fucntions is call
> > to usb_read_10/usb_write_10 scsi commands.
> >
> > Signed-off-by: Rajesh Bhagat <rajesh.bhagat@nxp.com>
> > ---
> > Changes in v6:
> >  - Removes USB_STOR_OP_TYPE macro and adds __func__ in debug prints
> >  - Unifies usb_read_10/usb_write_10 functions to usb_read_write_10
> >
> > Changes in v5:
> >  - Converts USB_STOR_OPERATION_FUNC macro to a function
> >  - Corrects the multi line comment accroding to coding style
> >  - Renames variable to dev to remove code duplication
> >
> > Changes in v4:
> >  - Adds code to make common function for read/write
> >
> >  common/usb_storage.c | 147
> > +++++++++++++--------------------------------------
> >  1 file changed, 36 insertions(+), 111 deletions(-)
> >
> > diff --git a/common/usb_storage.c b/common/usb_storage.c index
> > 7e6e52d..41e5aa3 100644
> > --- a/common/usb_storage.c
> > +++ b/common/usb_storage.c
> > @@ -1046,11 +1046,11 @@ static int usb_read_capacity(ccb *srb, struct us_data
> *ss)
> >  	return -1;
> >  }
> >
> > -static int usb_read_10(ccb *srb, struct us_data *ss, unsigned long start,
> > -		       unsigned short blocks)
> > +static int usb_read_write_10(ccb *srb, struct us_data *ss, unsigned long start,
> > +		       unsigned short blocks, bool is_write)
> >  {
> >  	memset(&srb->cmd[0], 0, 12);
> > -	srb->cmd[0] = SCSI_READ10;
> > +	srb->cmd[0] = is_write ? SCSI_WRITE10 : SCSI_READ10;
> >  	srb->cmd[1] = srb->lun << 5;
> >  	srb->cmd[2] = ((unsigned char) (start >> 24)) & 0xff;
> >  	srb->cmd[3] = ((unsigned char) (start >> 16)) & 0xff; @@ -1059,28
> > +1059,10 @@ static int usb_read_10(ccb *srb, struct us_data *ss, unsigned long
> start,
> >  	srb->cmd[7] = ((unsigned char) (blocks >> 8)) & 0xff;
> >  	srb->cmd[8] = (unsigned char) blocks & 0xff;
> >  	srb->cmdlen = 12;
> > -	debug("read10: start %lx blocks %x\n", start, blocks);
> > +	debug("%s: start %lx blocks %x\n", __func__, start, blocks);
> >  	return ss->transport(srb, ss);
> >  }
> >
> > -static int usb_write_10(ccb *srb, struct us_data *ss, unsigned long start,
> > -			unsigned short blocks)
> > -{
> > -	memset(&srb->cmd[0], 0, 12);
> > -	srb->cmd[0] = SCSI_WRITE10;
> > -	srb->cmd[1] = srb->lun << 5;
> > -	srb->cmd[2] = ((unsigned char) (start >> 24)) & 0xff;
> > -	srb->cmd[3] = ((unsigned char) (start >> 16)) & 0xff;
> > -	srb->cmd[4] = ((unsigned char) (start >> 8)) & 0xff;
> > -	srb->cmd[5] = ((unsigned char) (start)) & 0xff;
> > -	srb->cmd[7] = ((unsigned char) (blocks >> 8)) & 0xff;
> > -	srb->cmd[8] = (unsigned char) blocks & 0xff;
> > -	srb->cmdlen = 12;
> > -	debug("write10: start %lx blocks %x\n", start, blocks);
> > -	return ss->transport(srb, ss);
> > -}
> > -

Hello Marek, 

> 
> This stuff should be in a separate patch, otherwise it's not bisectable.
> Looks pretty OK otherwise.

Will take care in v7.

Best Regards,
Rajesh Bhagat 

> 
> [...]
> 
> --
> Best regards,
> Marek Vasut