libata: Fix accesses at LBA28 boundary (old bug, but nasty) (v2)

commit 45c4d015a92f72ec47acd0c7557abdc0c8a6499d upstream.

Most drives from Seagate, Hitachi, and possibly other brands,
do not allow LBA28 access to sector number 0x0fffffff (2^28 - 1).
So instead use LBA48 for such accesses.

This bug could bite a lot of systems, especially when the user has
taken care to align partitions to 4KB boundaries. On misaligned systems,
it is less likely to be encountered, since a 4KB read would end at
0x10000000 rather than at 0x0fffffff.

Signed-off-by: Mark Lord <mlord@pobox.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/include/linux/ata.h b/include/linux/ata.h
index 4fb357312b3bf4b4484879fa5ede0942e39fb15f..89387962f5f57291b289846f92d55e8203ccaf11 100644 (file)
--- a/include/linux/ata.h
+++ b/include/linux/ata.h
@@ -1000,8 +1000,8 @@ static inline int ata_ok(u8 status)
 
 static inline int lba_28_ok(u64 block, u32 n_block)
 {
-       /* check the ending block number */
-       return ((block + n_block) < ((u64)1 << 28)) && (n_block <= 256);
+       /* check the ending block number: must be LESS THAN 0x0fffffff */
+       return ((block + n_block) < ((1 << 28) - 1)) && (n_block <= 256);
 }
 
 static inline int lba_48_ok(u64 block, u32 n_block)