libata: fix bug with non-ncq devices
authorJens Axboe <jens.axboe@oracle.com>
Fri, 24 Oct 2008 07:22:42 +0000 (09:22 +0200)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 24 Oct 2008 15:22:38 +0000 (08:22 -0700)
commite013e13bf605b9e6b702adffbe2853cfc60e7806
treef69ce0b35fa8df2447d06eee64f4f579b883e701
parent57f8f7b60db6f1ed2c6918ab9230c4623a9dbe37
libata: fix bug with non-ncq devices

The recent commit 2fca5ccf97d2c28bcfce44f5b07d85e74e3cd18e ("libata:
switch to using block layer tagging support") to enable support for
block layer tagging in libata was broken for non-NCQ devices

The block layer initializes the tag field to -1 to detect invalid uses
of a tag, and if the libata devices does NOT support NCQ, we just used
that field to index the internal command list.  So we need to check for
-1 first and only use the tag field if it's valid.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Reported-by: Alexander Beregalov <a.beregalov@gmail.com>
Tested-by: Paul Mundt <lethal@linux-sh.org>
Tested-by: Dave Young <hidave.darkstar@gmail.com>
Tested-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
drivers/ata/libata-scsi.c