ide-cd: document capacity hack
Just copy the comment from drivers/scsi/sr.c::sr_done()
(from which the capacity hack has been originated).
Cc: Borislav Petkov <petkovbb@gmail.com>
Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/drivers/ide/ide-cd.c b/drivers/ide/ide-cd.c
index 0bfeb0c..690475b 100644
--- a/drivers/ide/ide-cd.c
+++ b/drivers/ide/ide-cd.c
@@ -194,6 +194,14 @@
bio_sectors = max(bio_sectors(failed_command->bio), 4U);
sector &= ~(bio_sectors - 1);
+ /*
+ * The SCSI specification allows for the value
+ * returned by READ CAPACITY to be up to 75 2K
+ * sectors past the last readable block.
+ * Therefore, if we hit a medium error within the
+ * last 75 2K sectors, we decrease the saved size
+ * value.
+ */
if (sector < get_capacity(info->disk) &&
drive->probed_capacity - sector < 4 * 75)
set_capacity(info->disk, sector);
