ide-gd: implement block device ->set_capacity method (v2)

* Use ->probed_capacity to store native device capacity for ATA disks.

* Add ->set_capacity method to struct ide_disk_ops.

* Implement disk device ->set_capacity method for ATA disks.

* Implement block device ->set_capacity method.

v2:
* Check if LBA and HPA are supported in ide_disk_set_capacity().

* According to the spec the SET MAX ADDRESS command shall be
  immediately preceded by a READ NATIVE MAX ADDRESS command.

* Add ide_disk_hpa_{get_native,set}_capacity() helpers.

Together with the previous patch adding ->set_capacity block device
method this allows automatic disabling of Host Protected Area (HPA)
if any partitions overlapping HPA are detected.

Cc: Robert Hancock <hancockrwd@gmail.com>
Cc: Frans Pop <elendil@planet.nl>
Cc: "Andries E. Brouwer" <Andries.Brouwer@cwi.nl>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Emphatically-Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

3 files changed, 72 insertions, 13 deletions

diff --git a/drivers/ide/ide-disk.c b/drivers/ide/ide-disk.c
index a9fbe2c31210..61a6d3546221 100644
--- a/drivers/ide/ide-disk.c
+++ b/drivers/ide/ide-disk.c
@@ -302,14 +302,12 @@ static const struct drive_list_entry hpa_list[] = {
         { NULL,         NULL }
 };
 
-static void idedisk_check_hpa(ide_drive_t *drive)
+static u64 ide_disk_hpa_get_native_capacity(ide_drive_t *drive, int lba48)
 {
-        unsigned long long capacity, set_max;
-        int lba48 = ata_id_lba48_enabled(drive->id);
+        u64 capacity, set_max;
 
         capacity = drive->capacity64;
-
-        set_max = idedisk_read_native_max_address(drive, lba48);
+        set_max  = idedisk_read_native_max_address(drive, lba48);
 
         if (ide_in_drive_list(drive->id, hpa_list)) {
                 /*
@@ -320,9 +318,31 @@ static void idedisk_check_hpa(ide_drive_t *drive)
                         set_max--;
         }
 
+        return set_max;
+}
+
+static u64 ide_disk_hpa_set_capacity(ide_drive_t *drive, u64 set_max, int lba48)
+{
+        set_max = idedisk_set_max_address(drive, set_max, lba48);
+        if (set_max)
+                drive->capacity64 = set_max;
+
+        return set_max;
+}
+
+static void idedisk_check_hpa(ide_drive_t *drive)
+{
+        u64 capacity, set_max;
+        int lba48 = ata_id_lba48_enabled(drive->id);
+
+        capacity = drive->capacity64;
+        set_max  = ide_disk_hpa_get_native_capacity(drive, lba48);
+
         if (set_max <= capacity)
                 return;
 
+        drive->probed_capacity = set_max;
+
         printk(KERN_INFO "%s: Host Protected Area detected.\n"
                          "\tcurrent capacity is %llu sectors (%llu MB)\n"
                          "\tnative  capacity is %llu sectors (%llu MB)\n",
@@ -330,13 +350,10 @@ static void idedisk_check_hpa(ide_drive_t *drive)
                          capacity, sectors_to_MB(capacity),
                          set_max, sectors_to_MB(set_max));
 
-        set_max = idedisk_set_max_address(drive, set_max, lba48);
-
-        if (set_max) {
-                drive->capacity64 = set_max;
+        set_max = ide_disk_hpa_set_capacity(drive, set_max, lba48);
+        if (set_max)
                 printk(KERN_INFO "%s: Host Protected Area disabled.\n",
                                  drive->name);
-        }
 }
 
 static int ide_disk_get_capacity(ide_drive_t *drive)
@@ -358,6 +375,8 @@ static int ide_disk_get_capacity(ide_drive_t *drive)
                 drive->capacity64 = drive->cyl * drive->head * drive->sect;
         }
 
+        drive->probed_capacity = drive->capacity64;
+
         if (lba) {
                 drive->dev_flags |= IDE_DFLAG_LBA;
 
@@ -376,7 +395,7 @@ static int ide_disk_get_capacity(ide_drive_t *drive)
                        "%llu sectors (%llu MB)\n",
                        drive->name, (unsigned long long)drive->capacity64,
                        sectors_to_MB(drive->capacity64));
-                drive->capacity64 = 1ULL << 28;
+                drive->probed_capacity = drive->capacity64 = 1ULL << 28;
         }
 
         if ((drive->hwif->host_flags & IDE_HFLAG_NO_LBA48_DMA) &&
@@ -392,6 +411,31 @@ static int ide_disk_get_capacity(ide_drive_t *drive)
         return 0;
 }
 
+static u64 ide_disk_set_capacity(ide_drive_t *drive, u64 capacity)
+{
+        u64 set = min(capacity, drive->probed_capacity);
+        u16 *id = drive->id;
+        int lba48 = ata_id_lba48_enabled(id);
+
+        if ((drive->dev_flags & IDE_DFLAG_LBA) == 0 ||
+            ata_id_hpa_enabled(id) == 0)
+                goto out;
+
+        /*
+         * according to the spec the SET MAX ADDRESS command shall be
+         * immediately preceded by a READ NATIVE MAX ADDRESS command
+         */
+        capacity = ide_disk_hpa_get_native_capacity(drive, lba48);
+        if (capacity == 0)
+                goto out;
+
+        set = ide_disk_hpa_set_capacity(drive, set, lba48);
+        if (set)
+                return set;
+out:
+        return drive->capacity64;
+}
+
 static void idedisk_prepare_flush(struct request_queue *q, struct request *rq)
 {
         ide_drive_t *drive = q->queuedata;
@@ -741,6 +785,7 @@ static int ide_disk_set_doorlock(ide_drive_t *drive, struct gendisk *disk,
 
 const struct ide_disk_ops ide_ata_disk_ops = {
         .check          = ide_disk_check,
+        .set_capacity   = ide_disk_set_capacity,
         .get_capacity   = ide_disk_get_capacity,
         .setup          = ide_disk_setup,
         .flush          = ide_disk_flush,
diff --git a/drivers/ide/ide-gd.c b/drivers/ide/ide-gd.c
index 4b6b71e2cdf5..214119026b3f 100644
--- a/drivers/ide/ide-gd.c
+++ b/drivers/ide/ide-gd.c
@@ -287,6 +287,19 @@ static int ide_gd_media_changed(struct gendisk *disk)
         return ret;
 }
 
+static unsigned long long ide_gd_set_capacity(struct gendisk *disk,
+                                              unsigned long long capacity)
+{
+        struct ide_disk_obj *idkp = ide_drv_g(disk, ide_disk_obj);
+        ide_drive_t *drive = idkp->drive;
+        const struct ide_disk_ops *disk_ops = drive->disk_ops;
+
+        if (disk_ops->set_capacity)
+                return disk_ops->set_capacity(drive, capacity);
+
+        return drive->capacity64;
+}
+
 static int ide_gd_revalidate_disk(struct gendisk *disk)
 {
         struct ide_disk_obj *idkp = ide_drv_g(disk, ide_disk_obj);
@@ -315,6 +328,7 @@ static struct block_device_operations ide_gd_ops = {
         .locked_ioctl           = ide_gd_ioctl,
         .getgeo                 = ide_gd_getgeo,
         .media_changed          = ide_gd_media_changed,
+        .set_capacity           = ide_gd_set_capacity,
         .revalidate_disk        = ide_gd_revalidate_disk
 };
 
diff --git a/include/linux/ide.h b/include/linux/ide.h
index 9fed365a598b..e96ace12872a 100644
--- a/include/linux/ide.h
+++ b/include/linux/ide.h
@@ -397,6 +397,7 @@ struct ide_drive_s;
 struct ide_disk_ops {
         int             (*check)(struct ide_drive_s *, const char *);
         int             (*get_capacity)(struct ide_drive_s *);
+        u64             (*set_capacity)(struct ide_drive_s *, u64);
         void            (*setup)(struct ide_drive_s *);
         void            (*flush)(struct ide_drive_s *);
         int             (*init_media)(struct ide_drive_s *, struct gendisk *);
@@ -568,8 +569,7 @@ struct ide_drive_s {
         unsigned int    drive_data;     /* used by set_pio_mode/dev_select() */
         unsigned int    failures;       /* current failure count */
         unsigned int    max_failures;   /* maximum allowed failure count */
-        u64             probed_capacity;/* initial reported media capacity (ide-cd only currently) */
-
+        u64             probed_capacity;/* initial/native media capacity */
         u64             capacity64;     /* total number of sectors */
 
         int             lun;            /* logical unit */