libata: disable a disk via libata.force params

A user on StackExchange had a failing SSD that's soldered directly
onto the motherboard of his system. The BIOS does not give any option
to disable it at all, so he can't just hide it from the OS via the
BIOS.

The old IDE layer had hdX=noprobe override for situations like this,
but that was never ported to the libata layer.

This patch implements a disable flag for libata.force.

Example use:

 libata.force=2.0:disable

[v2 of the patch, removed the nodisable flag per Tejun Heo]

Signed-off-by: Robin H. Johnson <robbat2@gentoo.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org
Link: http://unix.stackexchange.com/questions/102648/how-to-tell-linux-kernel-3-0-to-completely-ignore-a-failing-disk
Link: http://askubuntu.com/questions/352836/how-can-i-tell-linux-kernel-to-completely-ignore-a-disk-as-if-it-was-not-even-co
Link: http://superuser.com/questions/599333/how-to-disable-kernel-probing-for-drive

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 50680a5..b9e9bd8 100644 (file)
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1529,6 +1529,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 
                        * atapi_dmadir: Enable ATAPI DMADIR bridge support
 
+                       * disable: Disable this device.
+
                        If there are multiple matching configurations changing
                        the same attribute, the last one is used.
 

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index dae73ef..ff01584 100644 (file)
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -6522,6 +6522,7 @@ static int __init ata_parse_force_one(char **cur,
                { "norst",      .lflags         = ATA_LFLAG_NO_HRST | ATA_LFLAG_NO_SRST },
                { "rstonce",    .lflags         = ATA_LFLAG_RST_ONCE },
                { "atapi_dmadir", .horkage_on   = ATA_HORKAGE_ATAPI_DMADIR },
+               { "disable",    .horkage_on     = ATA_HORKAGE_DISABLE },
        };
        char *start = *cur, *p = *cur;
        char *id, *val, *endp;