kernel26-35-lts-arch/libata-alignment.patch

   1 --- drivers/ata/libata-scsi.c   2011-02-07 06:04:07.000000000 +1100
   2 +++ drivers/ata/libata-scsi.c   2011-02-26 19:13:01.147238442 +1100
   3 @@ -1129,13 +1129,13 @@
   4         /* configure max sectors */
   5         blk_queue_max_hw_sectors(sdev->request_queue, dev->max_sectors);
   6
   7 +       sdev->sector_size = ATA_SECT_SIZE;
   8 +
   9         if (dev->class == ATA_DEV_ATAPI) {
  10                 struct request_queue *q = sdev->request_queue;
  11                 void *buf;
  12
  13 -               /* set the min alignment and padding */
  14 -               blk_queue_update_dma_alignment(sdev->request_queue,
  15 -                                              ATA_DMA_PAD_SZ - 1);
  16 +               /* set DMA padding */
  17                 blk_queue_update_dma_pad(sdev->request_queue,
  18                                          ATA_DMA_PAD_SZ - 1);
  19
  20 @@ -1149,12 +1149,24 @@
  21
  22                 blk_queue_dma_drain(q, atapi_drain_needed, buf, ATAPI_MAX_DRAIN);
  23         } else {
  24 -               /* ATA devices must be sector aligned */
  25 -               blk_queue_update_dma_alignment(sdev->request_queue,
  26 -                                              ATA_SECT_SIZE - 1);
  27                 sdev->manage_start_stop = 1;
  28         }
  29
  30 +       /*
  31 +        * ata_pio_sectors() expects buffer for each sector to not cross
  32 +        * page boundary.  Enforce it by requiring buffers to be sector
  33 +        * aligned, which works iff sector_size is not larger than
  34 +        * PAGE_SIZE.  ATAPI devices also need the alignment as
  35 +        * IDENTIFY_PACKET is executed as ATA_PROT_PIO.
  36 +        */
  37 +       if (sdev->sector_size > PAGE_SIZE)
  38 +               ata_dev_printk(dev, KERN_WARNING,
  39 +                       "sector_size=%u > PAGE_SIZE, PIO may malfunction\n",
  40 +                       sdev->sector_size);
  41 +
  42 +       blk_queue_update_dma_alignment(sdev->request_queue,
  43 +                                      sdev->sector_size - 1);
  44 +
  45         if (dev->flags & ATA_DFLAG_AN)
  46                 set_bit(SDEV_EVT_MEDIA_CHANGE, sdev->supported_events);
  47