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| author | Tejun Heo <tj@kernel.org> | 2009-04-15 22:10:24 +0900 |
|---|---|---|
| committer | Jens Axboe <jens.axboe@oracle.com> | 2009-04-22 08:35:09 +0200 |
| commit | 25636e282fe95508cae96bb27f86407aef935817 (patch) | |
| tree | 3ab5b1ab589c02756211c8faa098f756488ff0de /block | |
| parent | 23c560a99d78bddf5c251bfa97bce19e4da4b3f3 (diff) | |
| download | lwn-25636e282fe95508cae96bb27f86407aef935817.tar.gz lwn-25636e282fe95508cae96bb27f86407aef935817.zip | |
block: fix SG_IO vector request data length handling
Impact: fix SG_IO behavior such that it matches the documentation
SG_IO howto says that if ->dxfer_len and sum of iovec disagress, the
shorter one wins. However, the current implementation returns -EINVAL
for such cases. Trim iovc if it's longer than ->dxfer_len.
This patch uses iov_*() helpers which take struct iovec * by casting
struct sg_iovec * to it. sg_iovec is always identical to iovec and
this will be further cleaned up with later patches.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block')
| -rw-r--r-- | block/scsi_ioctl.c | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c index 84b7f8709f41..82a0ca2f6729 100644 --- a/block/scsi_ioctl.c +++ b/block/scsi_ioctl.c @@ -290,6 +290,7 @@ static int sg_io(struct request_queue *q, struct gendisk *bd_disk, if (hdr->iovec_count) { const int size = sizeof(struct sg_iovec) * hdr->iovec_count; + size_t iov_data_len; struct sg_iovec *iov; iov = kmalloc(size, GFP_KERNEL); @@ -304,8 +305,18 @@ static int sg_io(struct request_queue *q, struct gendisk *bd_disk, goto out; } + /* SG_IO howto says that the shorter of the two wins */ + iov_data_len = iov_length((struct iovec *)iov, + hdr->iovec_count); + if (hdr->dxfer_len < iov_data_len) { + hdr->iovec_count = iov_shorten((struct iovec *)iov, + hdr->iovec_count, + hdr->dxfer_len); + iov_data_len = hdr->dxfer_len; + } + ret = blk_rq_map_user_iov(q, rq, NULL, iov, hdr->iovec_count, - hdr->dxfer_len, GFP_KERNEL); + iov_data_len, GFP_KERNEL); kfree(iov); } else if (hdr->dxfer_len) ret = blk_rq_map_user(q, rq, NULL, hdr->dxferp, hdr->dxfer_len, |