[PATCH 02/11] libata: during revalidation, check n_sectors after device is configured

Tejun Heo
2007-05-05T16:28:11Z

Device might be resized during ata_dev_configure() due to HPA or
(later) ACPI _GTF. Currently it's worked around by caching n_sectors
before turning off HPA. The cached original size is overwritten if
the device is reconfigured without being hardreset - which always
happens after configuring trasnfer mode. If the device gets hardreset
for some reason after that, revalidation fails with -ENODEV.

This patch makes size checking more robust by moving n_sectors check
from ata_dev_reread_id() to ata_dev_revalidate() after the device is
fully configured. No matter what happens during configuration, a
device must have the same n_sectors after fully configured to be
treated as the same device.

Signed-off-by: Tejun Heo <htejun@gmail.com>
---
drivers/ata/libata-core.c | 33 +++++++++++++++------------------
include/linux/libata.h | 1 -
2 files changed, 15 insertions(+), 19 deletions(-)

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 9d0d753..f53aa87 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -1891,7 +1891,6 @@ int ata_dev_configure(struct ata_device *dev)
snprintf(revbuf, 7, "ATA-%d", ata_id_major_version(id));

dev->n_sectors = ata_id_n_sectors(id);
- dev->n_sectors_boot = dev->n_sectors;

/* SCSI only uses 4-char revisions, dump full 8 chars from ATA */
ata_id_c_string(dev->id, fwrevbuf, ATA_ID_FW_REV,
@@ -3554,7 +3553,6 @@ static int ata_dev_same_device(struct ata_device *dev, unsigned int new_class,
const u16 *old_id = dev->id;
unsigned char model[2][ATA_ID_PROD_LEN + 1];
unsigned char serial[2][ATA_ID_SERNO_LEN + 1];
- u64 new_n_sectors;

if (dev->class != new_class) {
ata_dev_printk(dev, KERN_INFO, "class mismatch %d != %d\n",
@@ -3566,7 +3564,6 @@ static int ata_dev_same_device(struct ata_device *dev, unsigned int new_class,
ata_id_c_string(new_id, model[1], ATA_ID_PROD, sizeof(model[1]));
ata_id_c_string(old_id, serial[0], ATA_ID_SERNO, sizeof(serial[0]));
ata_id_c_string(new_id, serial[1], ATA_ID_SERNO, sizeof(serial[1]));
- new_n_sectors = ata_id_n_sectors(new_id);

if (strcmp(model[0], model[1])) {
ata_dev_printk(dev, KERN_INFO, "model number mismatch "
@@ -3580,19 +3577,6 @@ static int ata_dev_same_device(struct ata_device *dev, unsigned int new_class,
return 0;
}

- if (dev->class == ATA_DEV_ATA && dev->n_sectors != new_n_sectors) {
- ata_dev_printk(dev, KERN_INFO, "n_sectors mismatch "
- "%llu != %llu\n",
- (unsigned long long)dev->n_sectors,
- (unsigned long long)new_n_sectors);
- /* Are we the boot time size - if so we appear to be the
- same disk at this point and our HPA got reapplied */
- if (ata_ignore_hpa && dev->n_sectors_boot == new_n_sectors
- && ata_id_hpa_enabled(new_id))
- return 1;
- return 0;
- }
-
return 1;
}

@@ -3645,6 +3629,7 @@ int ata_dev_reread_id(struct ata_device *dev, unsigned int readid_flags)
*/
int ata_dev_revalidate(struct ata_device *dev, unsigned int readid_flags)
{
+ u64 n_sectors = dev->n_sectors;
int rc;

if (!ata_dev_enabled(dev))
@@ -3657,8 +3642,20 @@ int ata_dev_revalidate(struct ata_device *dev, unsigned int readid_flags)

/* configure device according to the new ID */
rc = ata_dev_configure(dev);
- if (rc == 0)
- return 0;
+ if (rc)
+ goto fail;
+
+ /* verify n_sectors hasn't changed */
+ if (dev->class == ATA_DEV_ATA && dev->n_sectors != n_sectors) {
+ ata_dev_printk(dev, KERN_INFO, "n_sectors mismatch "
+ "%llu != %llu\n",
+ (unsigned long long)n_sectors,
+ (unsigned long long)dev->n_sectors);
+ rc = -ENODEV;
+ goto fail;
+ }
+
+ return 0;

fail:
ata_dev_printk(dev, KERN_ERR, "revalidation failed (errno=%d)\n", rc);
diff --git a/include/linux/libata.h b/include/linux/libata.h
index d8cfc72..3cffbf6 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -448,7 +448,6 @@ struct ata_device {
struct scsi_device *sdev; /* attached SCSI device */
/* n_sector is used as CLEAR_OFFSET, read comment above CLEAR_OFFSET */
u64 n_sectors; /* size of device, if ATA */
- u64 n_sectors_boot; /* size of ATA device at startup */
unsigned int class; /* ATA_DEV_xxx */
u16 id[ATA_ID_WORDS]; /* IDENTIFY xxx DEVICE data */
u8 pio_mode;
--
1.5.0.3