block: ensure bio_alloc_map_data() deals with ITER_UBUF correctly

This helper blindly copies the iovec, even if we don't have one.
Make this case a bit smarter by only doing so if we have an iovec
array to copy.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jens Axboe 2023-03-28 15:10:31 -06:00
parent 3a93e40326
commit 0a2481cde2

View File

@ -29,10 +29,11 @@ static struct bio_map_data *bio_alloc_map_data(struct iov_iter *data,
bmd = kmalloc(struct_size(bmd, iov, data->nr_segs), gfp_mask);
if (!bmd)
return NULL;
memcpy(bmd->iov, data->iov, sizeof(struct iovec) * data->nr_segs);
bmd->iter = *data;
if (iter_is_iovec(data))
if (iter_is_iovec(data)) {
memcpy(bmd->iov, data->iov, sizeof(struct iovec) * data->nr_segs);
bmd->iter.iov = bmd->iov;
}
return bmd;
}