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Commit 6ae4cfb5 authored by Albert Lee's avatar Albert Lee Committed by Jeff Garzik
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[PATCH] libata ata_data_xfer() fix 



PATCH 1/2: ata_data_xfer() fix

Changes:
   - Modify ata_mmio_data_xfer() and ata_pio_data_xfer() to handle odd-lengthed buffer.
   - Add some function comments

This patch does not reuse ap->pad as alignment buffer since
using local variable seems good enough.

Signed-off-by: default avatarAlbert Lee <albertcc@tw.ibm.com>
Signed-off-by: default avatarJeff Garzik <jgarzik@pobox.com>
parent bc68552f

drivers/scsi/libata-core.c

+108 −3
Original line number Diff line number Diff line
@@ -2519,6 +2519,20 @@ void swap_buf_le16(u16 *buf, unsigned int buf_words) 
#endif /* __BIG_ENDIAN */

}



/**

 *	ata_mmio_data_xfer - Transfer data by MMIO

 *	@ap: port to read/write

 *	@buf: data buffer

 *	@buflen: buffer length

 *	@do_write: read/write

 *

 *	Transfer data from/to the device data register by MMIO.

 *

 *	LOCKING:

 *	Inherited from caller.

 *

 */



static void ata_mmio_data_xfer(struct ata_port *ap, unsigned char *buf,

			       unsigned int buflen, int write_data)

{
@@ -2527,6 +2541,7 @@ static void ata_mmio_data_xfer(struct ata_port *ap, unsigned char *buf, 
	u16 *buf16 = (u16 *) buf;

	void __iomem *mmio = (void __iomem *)ap->ioaddr.data_addr;



	/* Transfer multiple of 2 bytes */

	if (write_data) {

		for (i = 0; i < words; i++)

			writew(le16_to_cpu(buf16[i]), mmio);
@@ -2534,18 +2549,75 @@ static void ata_mmio_data_xfer(struct ata_port *ap, unsigned char *buf, 
		for (i = 0; i < words; i++)

			buf16[i] = cpu_to_le16(readw(mmio));

	}



	/* Transfer trailing 1 byte, if any. */

	if (unlikely(buflen & 0x01)) {

		u16 align_buf[1] = { 0 };

		unsigned char *trailing_buf = buf + buflen - 1;



		if (write_data) {

			memcpy(align_buf, trailing_buf, 1);

			writew(le16_to_cpu(align_buf[0]), mmio);

		} else {

			align_buf[0] = cpu_to_le16(readw(mmio));

			memcpy(trailing_buf, align_buf, 1);

		}

	}

}



/**

 *	ata_pio_data_xfer - Transfer data by PIO

 *	@ap: port to read/write

 *	@buf: data buffer

 *	@buflen: buffer length

 *	@do_write: read/write

 *

 *	Transfer data from/to the device data register by PIO.

 *

 *	LOCKING:

 *	Inherited from caller.

 *

 */



static void ata_pio_data_xfer(struct ata_port *ap, unsigned char *buf,

			      unsigned int buflen, int write_data)

{

	unsigned int dwords = buflen >> 1;

	unsigned int words = buflen >> 1;



	/* Transfer multiple of 2 bytes */

	if (write_data)

		outsw(ap->ioaddr.data_addr, buf, dwords);

		outsw(ap->ioaddr.data_addr, buf, words);

	else

		insw(ap->ioaddr.data_addr, buf, dwords);

		insw(ap->ioaddr.data_addr, buf, words);



	/* Transfer trailing 1 byte, if any. */

	if (unlikely(buflen & 0x01)) {

		u16 align_buf[1] = { 0 };

		unsigned char *trailing_buf = buf + buflen - 1;



		if (write_data) {

			memcpy(align_buf, trailing_buf, 1);

			outw(le16_to_cpu(align_buf[0]), ap->ioaddr.data_addr);

		} else {

			align_buf[0] = cpu_to_le16(inw(ap->ioaddr.data_addr));

			memcpy(trailing_buf, align_buf, 1);

		}

	}

}



/**

 *	ata_data_xfer - Transfer data from/to the data register.

 *	@ap: port to read/write

 *	@buf: data buffer

 *	@buflen: buffer length

 *	@do_write: read/write

 *

 *	Transfer data from/to the device data register.

 *

 *	LOCKING:

 *	Inherited from caller.

 *

 */



static void ata_data_xfer(struct ata_port *ap, unsigned char *buf,

			  unsigned int buflen, int do_write)
@@ -2556,6 +2628,16 @@ static void ata_data_xfer(struct ata_port *ap, unsigned char *buf, 
		ata_pio_data_xfer(ap, buf, buflen, do_write);

}



/**

 *	ata_pio_sector - Transfer ATA_SECT_SIZE (512 bytes) of data.

 *	@qc: Command on going

 *

 *	Transfer ATA_SECT_SIZE of data from/to the ATA device.

 *

 *	LOCKING:

 *	Inherited from caller.

 */



static void ata_pio_sector(struct ata_queued_cmd *qc)

{

	int do_write = (qc->tf.flags & ATA_TFLAG_WRITE);
@@ -2594,6 +2676,18 @@ static void ata_pio_sector(struct ata_queued_cmd *qc) 
	kunmap(page);

}



/**

 *	__atapi_pio_bytes - Transfer data from/to the ATAPI device.

 *	@qc: Command on going

 *	@bytes: number of bytes

 *

 *	Transfer Transfer data from/to the ATAPI device.

 *

 *	LOCKING:

 *	Inherited from caller.

 *

 */



static void __atapi_pio_bytes(struct ata_queued_cmd *qc, unsigned int bytes)

{

	int do_write = (qc->tf.flags & ATA_TFLAG_WRITE);
@@ -2645,6 +2739,17 @@ static void __atapi_pio_bytes(struct ata_queued_cmd *qc, unsigned int bytes) 
	}

}



/**

 *	atapi_pio_bytes - Transfer data from/to the ATAPI device.

 *	@qc: Command on going

 *

 *	Transfer Transfer data from/to the ATAPI device.

 *

 *	LOCKING:

 *	Inherited from caller.

 *

 */



static void atapi_pio_bytes(struct ata_queued_cmd *qc)

{

	struct ata_port *ap = qc->ap;