From ac8672ea922bde59acf50eaa1eaa1640a6395fd2 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Sun, 16 Aug 2009 21:21:21 +0900 Subject: [PATCH] libata: fix off-by-one error in ata_tf_read_block() ata_tf_read_block() has off-by-one error when converting CHS address to LBA. The bug isn't very visible because ata_tf_read_block() is used only when generating sense data for a failed RW command and CHS addressing isn't used too often these days. This problem was spotted by Atsushi Nemoto. Signed-off-by: Tejun Heo Reported-by: Atsushi Nemoto Signed-off-by: Jeff Garzik --- drivers/ata/libata-core.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c index 98af50f16e0..df31deac5c8 100644 --- a/drivers/ata/libata-core.c +++ b/drivers/ata/libata-core.c @@ -709,7 +709,13 @@ u64 ata_tf_read_block(struct ata_taskfile *tf, struct ata_device *dev) head = tf->device & 0xf; sect = tf->lbal; - block = (cyl * dev->heads + head) * dev->sectors + sect; + if (!sect) { + ata_dev_printk(dev, KERN_WARNING, "device reported " + "invalid CHS sector 0\n"); + sect = 1; /* oh well */ + } + + block = (cyl * dev->heads + head) * dev->sectors + sect - 1; } return block; -- 2.20.1