1 files changed, 18 insertions, 6 deletions

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 5defc74973d7..600f6353ecf8 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -1099,9 +1099,9 @@ 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);
 
@@ -1115,13 +1115,25 @@ 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 */
                 sdev->sector_size = ata_id_logical_sector_size(dev->id);
-                blk_queue_update_dma_alignment(sdev->request_queue,
-                                               sdev->sector_size - 1);
                 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);