commit 77285121573198280db62ac2bfa79bed7ce09eca
Author: Anton Protopopov <aspsk@altlinux.org>
Date:   Wed Feb 9 15:55:08 2011 +0300

    Backport 729a6a300e628a48cf12bac93a964a535e83cd1d

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 6f6621a..377fdf5 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -1104,9 +1104,9 @@ static int ata_scsi_dev_config(struct scsi_device *sdev,
 		struct request_queue *q = sdev->request_queue;
 		void *buf;
 
-		/* set the min alignment and padding */
-		blk_queue_update_dma_alignment(sdev->request_queue,
-					       ATA_DMA_PAD_SZ - 1);
+		sdev->sector_size = ATA_SECT_SIZE;
+
+		/* set DMA padding */
 		blk_queue_update_dma_pad(sdev->request_queue,
 					 ATA_DMA_PAD_SZ - 1);
 
@@ -1120,12 +1120,25 @@ static int ata_scsi_dev_config(struct scsi_device *sdev,
 
 		blk_queue_dma_drain(q, atapi_drain_needed, buf, ATAPI_MAX_DRAIN);
 	} else {
-		/* ATA devices must be sector aligned */
-		blk_queue_update_dma_alignment(sdev->request_queue,
-					       ATA_SECT_SIZE - 1);
+		sdev->sector_size = ata_id_logical_sector_size(dev->id);
 		sdev->manage_start_stop = 1;
 	}
 
+	/*
+	 * ata_pio_sectors() expects buffer for each sector to not cross
+	 * page boundary.  Enforce it by requiring buffers to be sector
+	 * aligned, which works iff sector_size is not larger than
+	 * PAGE_SIZE.  ATAPI devices also need the alignment as
+	 * IDENTIFY_PACKET is executed as ATA_PROT_PIO.
+	 */
+	if (sdev->sector_size > PAGE_SIZE)
+		ata_dev_printk(dev, KERN_WARNING,
+			"sector_size=%u > PAGE_SIZE, PIO may malfunction\n",
+			sdev->sector_size);
+
+	blk_queue_update_dma_alignment(sdev->request_queue,
+				       sdev->sector_size - 1);
+
 	if (dev->flags & ATA_DFLAG_AN)
 		set_bit(SDEV_EVT_MEDIA_CHANGE, sdev->supported_events);
 
diff --git a/include/linux/ata.h b/include/linux/ata.h
index f8bd0f9..6e150c2 100644
--- a/include/linux/ata.h
+++ b/include/linux/ata.h
@@ -89,6 +89,7 @@ enum {
 	ATA_ID_SPG		= 98,
 	ATA_ID_LBA_CAPACITY_2	= 100,
 	ATA_ID_SECTOR_SIZE	= 106,
+	ATA_ID_LOGICAL_SECTOR_SIZE = 117, /* and 118 */
 	ATA_ID_LAST_LUN		= 126,
 	ATA_ID_DLF		= 128,
 	ATA_ID_CSFO		= 129,
@@ -640,6 +641,18 @@ static inline int ata_id_flush_ext_enabled(const u16 *id)
 	return (id[ATA_ID_CFS_ENABLE_2] & 0x2400) == 0x2400;
 }
 
+static inline u32 ata_id_logical_sector_size(const u16 *id)
+{
+	/* T13/1699-D Revision 6a, Sep 6, 2008. Page 128.
+	 * IDENTIFY DEVICE data, word 117-118.
+	 * 0xd000 ignores bit 13 (logical:physical > 1)
+	 */
+	if ((id[ATA_ID_SECTOR_SIZE] & 0xd000) == 0x5000)
+		return (((id[ATA_ID_LOGICAL_SECTOR_SIZE+1] << 16)
+					+ id[ATA_ID_LOGICAL_SECTOR_SIZE]) * sizeof(u16)) ;
+	return ATA_SECT_SIZE;
+}
+
 static inline int ata_id_has_large_logical_sectors(const u16 *id)
 {
 	if ((id[ATA_ID_SECTOR_SIZE] & 0xc000) != 0x4000)