[U-Boot] [PATCH] ahci: Fix a wrong parameter pass

[U-Boot] [PATCH] ahci: Fix a wrong parameter pass

[Yuantian.Tang at freescale.com]

From: Tang Yuantian <Yuantian.Tang@freescale.com>

In stead of user_buffer_size, transfer_size should be used to pass to
ahci_device_data_io(). transfer_size is the length that we want the
low level function to transfer each time.
If we use user_buffer_size which is the totally data length as parameter,
low level function will actually create many SGs to transfer as many data
as possible each time. That will produce many redundant data transfer.

Signed-off-by: Tang Yuantian <Yuantian.Tang@freescale.com>
---
 drivers/block/ahci.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/block/ahci.c b/drivers/block/ahci.c
index c908fab..88b90e0 100644
--- a/drivers/block/ahci.c
+++ b/drivers/block/ahci.c
@@ -785,7 +785,7 @@ static int ata_scsiop_read_write(ccb *pccb, u8 is_write)
 
 		/* Read/Write from ahci */
 		if (ahci_device_data_io(pccb->target, (u8 *) &fis, sizeof(fis),
-					user_buffer, user_buffer_size,
+					user_buffer, transfer_size,
 					is_write)) {
 			debug("scsi_ahci: SCSI %s10 command failure.\n",
 			      is_write ? "WRITE" : "READ");
-- 
2.1.0.27.g96db324

[U-Boot] [PATCH] ahci: Fix a wrong parameter pass

[Simon Glass]

On 31 March 2015 at 01:02,  <Yuantian.Tang@freescale.com> wrote:
> From: Tang Yuantian <Yuantian.Tang@freescale.com>
>
> In stead of user_buffer_size, transfer_size should be used to pass to
> ahci_device_data_io(). transfer_size is the length that we want the
> low level function to transfer each time.
> If we use user_buffer_size which is the totally data length as parameter,
> low level function will actually create many SGs to transfer as many data
> as possible each time. That will produce many redundant data transfer.
>
> Signed-off-by: Tang Yuantian <Yuantian.Tang@freescale.com>
> ---
>  drivers/block/ahci.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

I'm not an expert here but this looks right.

Reviewed-by: Simon Glass <sjg@chromium.org>

[U-Boot] ahci: Fix a wrong parameter pass

[Tom Rini]

On Tue, Mar 31, 2015 at 03:02:43PM +0800, tang yuantian wrote:

> From: Tang Yuantian <Yuantian.Tang@freescale.com>
> 
> In stead of user_buffer_size, transfer_size should be used to pass to
> ahci_device_data_io(). transfer_size is the length that we want the
> low level function to transfer each time.
> If we use user_buffer_size which is the totally data length as parameter,
> low level function will actually create many SGs to transfer as many data
> as possible each time. That will produce many redundant data transfer.
> 
> Signed-off-by: Tang Yuantian <Yuantian.Tang@freescale.com>
> Reviewed-by: Simon Glass <sjg@chromium.org>

Applied to u-boot/master, thanks!

-- 
Tom
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