diff options
| author | Mark Lord <liml@rtr.ca> | 2009-03-19 13:32:21 -0400 |
|---|---|---|
| committer | Jeff Garzik <jgarzik@redhat.com> | 2009-03-24 22:40:05 -0400 |
| commit | e18086d69cb5bb864749a0637f6ac573aa89d5ea (patch) | |
| tree | 2d3e541787eb30743693dd45c96ebabb9be0f0a6 /drivers/ata/libata-core.c | |
| parent | 000b344f4ca7828ee43940255c8bbb32e2c7dbec (diff) | |
[libata] More robust parsing for IDENTIFY DEVICE multi_count field
Make libata more robust when parsing the multi_count
field from a drive's identify data. This prevents us from
attempting to use dubious multi_count values ad infinitum.
Reset dev->multi_count to zero and reprobe it each time
through this routine, as it can change on device reset.
Also ensure that the reported "maximum" value is valid
and is a power of two, and that the reported "count" value
is valid and also a power of two. And that the "count"
value is not greater than the "maximum" value.
Signed-off-by: Mark Lord <mlord@pobox.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Diffstat (limited to 'drivers/ata/libata-core.c')
| -rw-r--r-- | drivers/ata/libata-core.c | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c index d4a7b8a96ec..e7ea77cf606 100644 --- a/drivers/ata/libata-core.c +++ b/drivers/ata/libata-core.c @@ -57,6 +57,7 @@ #include <linux/scatterlist.h> #include <linux/io.h> #include <linux/async.h> +#include <linux/log2.h> #include <scsi/scsi.h> #include <scsi/scsi_cmnd.h> #include <scsi/scsi_host.h> @@ -2389,6 +2390,7 @@ int ata_dev_configure(struct ata_device *dev) dev->cylinders = 0; dev->heads = 0; dev->sectors = 0; + dev->multi_count = 0; /* * common ATA, ATAPI feature tests @@ -2426,8 +2428,15 @@ int ata_dev_configure(struct ata_device *dev) dev->n_sectors = ata_id_n_sectors(id); - if (dev->id[59] & 0x100) - dev->multi_count = dev->id[59] & 0xff; + /* get current R/W Multiple count setting */ + if ((dev->id[47] >> 8) == 0x80 && (dev->id[59] & 0x100)) { + unsigned int max = dev->id[47] & 0xff; + unsigned int cnt = dev->id[59] & 0xff; + /* only recognize/allow powers of two here */ + if (is_power_of_2(max) && is_power_of_2(cnt)) + if (cnt <= max) + dev->multi_count = cnt; + } if (ata_id_has_lba(id)) { const char *lba_desc; |