libata: Implement disk shock protection support

On user request (through sysfs), the IDLE IMMEDIATE command with UNLOAD
FEATURE as specified in ATA-7 is issued to the device and processing of
the request queue is stopped thereafter until the specified timeout
expires or user space asks to resume normal operation. This is supposed
to prevent the heads of a hard drive from accidentally crashing onto the
platter when a heavy shock is anticipated (like a falling laptop
expected to hit the floor). In fact, the whole port stops processing
commands until the timeout has expired in order to avoid any resets due
to failed commands on another device.

Signed-off-by: Elias Oltmanns <eo@nebensachen.de>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 11 insertions, 2 deletions

diff --git a/include/linux/libata.h b/include/linux/libata.h
index 244ff601559a..1f44cfb847e1 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -146,6 +146,7 @@ enum {
         ATA_DFLAG_SPUNDOWN      = (1 << 14), /* XXX: for spindown_compat */
         ATA_DFLAG_SLEEPING      = (1 << 15), /* device is sleeping */
         ATA_DFLAG_DUBIOUS_XFER  = (1 << 16), /* data transfer not verified */
+        ATA_DFLAG_NO_UNLOAD     = (1 << 17), /* device doesn't support unload */
         ATA_DFLAG_INIT_MASK     = (1 << 24) - 1,
 
         ATA_DFLAG_DETACH        = (1 << 24),
@@ -244,6 +245,7 @@ enum {
         ATA_TMOUT_BOOT          = 30000,        /* heuristic */
         ATA_TMOUT_BOOT_QUICK    =  7000,        /* heuristic */
         ATA_TMOUT_INTERNAL_QUICK = 5000,
+        ATA_TMOUT_MAX_PARK      = 30000,
 
         /* FIXME: GoVault needs 2s but we can't afford that without
          * parallel probing.  800ms is enough for iVDR disk
@@ -319,8 +321,9 @@ enum {
         ATA_EH_RESET            = ATA_EH_SOFTRESET | ATA_EH_HARDRESET,
         ATA_EH_ENABLE_LINK      = (1 << 3),
         ATA_EH_LPM              = (1 << 4),  /* link power management action */
+        ATA_EH_PARK             = (1 << 5), /* unload heads and stop I/O */
 
-        ATA_EH_PERDEV_MASK      = ATA_EH_REVALIDATE,
+        ATA_EH_PERDEV_MASK      = ATA_EH_REVALIDATE | ATA_EH_PARK,
         ATA_EH_ALL_ACTIONS      = ATA_EH_REVALIDATE | ATA_EH_RESET |
                                   ATA_EH_ENABLE_LINK | ATA_EH_LPM,
 
@@ -454,6 +457,7 @@ enum link_pm {
         MEDIUM_POWER,
 };
 extern struct device_attribute dev_attr_link_power_management_policy;
+extern struct device_attribute dev_attr_unload_heads;
 extern struct device_attribute dev_attr_em_message_type;
 extern struct device_attribute dev_attr_em_message;
 extern struct device_attribute dev_attr_sw_activity;
@@ -566,6 +570,7 @@ struct ata_device {
         /* n_sector is used as CLEAR_OFFSET, read comment above CLEAR_OFFSET */
         u64                     n_sectors;      /* size of device, if ATA */
         unsigned int            class;          /* ATA_DEV_xxx */
+        unsigned long           unpark_deadline;
 
         u8                      pio_mode;
         u8                      dma_mode;
@@ -623,6 +628,7 @@ struct ata_eh_context {
                                                [ATA_EH_CMD_TIMEOUT_TABLE_SIZE];
         unsigned int            classes[ATA_MAX_DEVICES];
         unsigned int            did_probe_mask;
+        unsigned int            unloaded_mask;
         unsigned int            saved_ncq_enabled;
         u8                      saved_xfer_mode[ATA_MAX_DEVICES];
         /* timestamp for the last reset attempt or success */
@@ -712,6 +718,7 @@ struct ata_port {
         struct list_head        eh_done_q;
         wait_queue_head_t       eh_wait_q;
         int                     eh_tries;
+        struct completion       park_req_pending;
 
         pm_message_t            pm_mesg;
         int                     *pm_result;
@@ -1102,6 +1109,7 @@ extern void ata_std_error_handler(struct ata_port *ap);
  */
 extern const struct ata_port_operations ata_base_port_ops;
 extern const struct ata_port_operations sata_port_ops;
+extern struct device_attribute *ata_common_sdev_attrs[];
 
 #define ATA_BASE_SHT(drv_name)                                  \
         .module                 = THIS_MODULE,                  \
@@ -1116,7 +1124,8 @@ extern const struct ata_port_operations sata_port_ops;
         .proc_name              = drv_name,                     \
         .slave_configure        = ata_scsi_slave_config,        \
         .slave_destroy          = ata_scsi_slave_destroy,       \
-        .bios_param             = ata_std_bios_param
+        .bios_param             = ata_std_bios_param,           \
+        .sdev_attrs             = ata_common_sdev_attrs
 
 #define ATA_NCQ_SHT(drv_name)                                   \
         ATA_BASE_SHT(drv_name),                                 \