aboutsummaryrefslogtreecommitdiff
path: root/block/ioctl.c
diff options
context:
space:
mode:
authorDavid Woodhouse <David.Woodhouse@intel.com>2008-08-11 15:58:42 +0100
committerJens Axboe <jens.axboe@oracle.com>2008-10-09 08:56:02 +0200
commitd30a2605be9d5132d95944916e8f578fcfe4f976 (patch)
tree91a8161cb09536ab838ef47fceabb0da0bea9256 /block/ioctl.c
parent2ebca85abcfcbaaf1c0b242e39fc88ad3da90090 (diff)
downloadlinaro-lsk-d30a2605be9d5132d95944916e8f578fcfe4f976.tar.gz
Add BLKDISCARD ioctl to allow userspace to discard sectors
We may well want mkfs tools to use this to mark the whole device as unwanted before they format it, for example. The ioctl takes a pair of uint64_ts, which are start offset and length in _bytes_. Although at the moment it might make sense for them both to be in 512-byte sectors, I don't want to limit the ABI to that. Signed-off-by: David Woodhouse <David.Woodhouse@intel.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block/ioctl.c')
-rw-r--r--block/ioctl.c76
1 files changed, 76 insertions, 0 deletions
diff --git a/block/ioctl.c b/block/ioctl.c
index 77185e5c026..342298bb608 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -111,6 +111,69 @@ static int blkdev_reread_part(struct block_device *bdev)
return res;
}
+static void blk_ioc_discard_endio(struct bio *bio, int err)
+{
+ if (err) {
+ if (err == -EOPNOTSUPP)
+ set_bit(BIO_EOPNOTSUPP, &bio->bi_flags);
+ clear_bit(BIO_UPTODATE, &bio->bi_flags);
+ }
+ complete(bio->bi_private);
+}
+
+static int blk_ioctl_discard(struct block_device *bdev, uint64_t start,
+ uint64_t len)
+{
+ struct request_queue *q = bdev_get_queue(bdev);
+ int ret = 0;
+
+ if (start & 511)
+ return -EINVAL;
+ if (len & 511)
+ return -EINVAL;
+ start >>= 9;
+ len >>= 9;
+
+ if (start + len > (bdev->bd_inode->i_size >> 9))
+ return -EINVAL;
+
+ if (!q->prepare_discard_fn)
+ return -EOPNOTSUPP;
+
+ while (len && !ret) {
+ DECLARE_COMPLETION_ONSTACK(wait);
+ struct bio *bio;
+
+ bio = bio_alloc(GFP_KERNEL, 0);
+ if (!bio)
+ return -ENOMEM;
+
+ bio->bi_end_io = blk_ioc_discard_endio;
+ bio->bi_bdev = bdev;
+ bio->bi_private = &wait;
+ bio->bi_sector = start;
+
+ if (len > q->max_hw_sectors) {
+ bio->bi_size = q->max_hw_sectors << 9;
+ len -= q->max_hw_sectors;
+ start += q->max_hw_sectors;
+ } else {
+ bio->bi_size = len << 9;
+ len = 0;
+ }
+ submit_bio(WRITE_DISCARD, bio);
+
+ wait_for_completion(&wait);
+
+ if (bio_flagged(bio, BIO_EOPNOTSUPP))
+ ret = -EOPNOTSUPP;
+ else if (!bio_flagged(bio, BIO_UPTODATE))
+ ret = -EIO;
+ bio_put(bio);
+ }
+ return ret;
+}
+
static int put_ushort(unsigned long arg, unsigned short val)
{
return put_user(val, (unsigned short __user *)arg);
@@ -258,6 +321,19 @@ int blkdev_ioctl(struct inode *inode, struct file *file, unsigned cmd,
set_device_ro(bdev, n);
unlock_kernel();
return 0;
+
+ case BLKDISCARD: {
+ uint64_t range[2];
+
+ if (!(file->f_mode & FMODE_WRITE))
+ return -EBADF;
+
+ if (copy_from_user(range, (void __user *)arg, sizeof(range)))
+ return -EFAULT;
+
+ return blk_ioctl_discard(bdev, range[0], range[1]);
+ }
+
case HDIO_GETGEO: {
struct hd_geometry geo;