Re: [PATCH for-next v7 3/5] nvme: refactor nvme_alloc_user_request
From: Christoph Hellwig <hch@lst.de>
Date: 2022-09-20 12:02:36
Also in:
io-uring, linux-nvme
On Fri, Sep 09, 2022 at 03:51:34PM +0530, Kanchan Joshi wrote:
quoted hunk ↗ jump to hunk
Separate this out to two functions with reduced number of arguments. _ Signed-off-by: Kanchan Joshi <redacted> --- drivers/nvme/host/ioctl.c | 116 ++++++++++++++++++++++---------------- 1 file changed, 66 insertions(+), 50 deletions(-)diff --git a/drivers/nvme/host/ioctl.c b/drivers/nvme/host/ioctl.c index 548aca8b5b9f..cb2fa4db50dd 100644 --- a/drivers/nvme/host/ioctl.c +++ b/drivers/nvme/host/ioctl.c@@ -65,18 +65,10 @@ static int nvme_finish_user_metadata(struct request *req, void __user *ubuf, } static struct request *nvme_alloc_user_request(struct request_queue *q, + struct nvme_command *cmd, unsigned timeout, blk_opf_t rq_flags, blk_mq_req_flags_t blk_flags)
I think we can also drop the timeout flag here, which seems like it can be handled cleaner in the callers. to set it can just do that.
+static int nvme_map_user_request(struct request *req, void __user *ubuffer,
+ unsigned bufflen, void __user *meta_buffer, unsigned meta_len,
+ u32 meta_seed, void **metap, bool vec)
+{
+ struct request_queue *q = req->q;
+ struct nvme_ns *ns = q->queuedata;
+ struct block_device *bdev = ns ? ns->disk->part0 : NULL;
+ struct bio *bio = NULL;
+ void *meta = NULL;
+ int ret;
+
+ if (!ubuffer || !bufflen)
+ return 0;I'd leave these in the callers and not call the helper if there is no data to transfer.
+
+ if (!vec)
+ ret = blk_rq_map_user(q, req, NULL, ubuffer, bufflen,
+ GFP_KERNEL);
+ else {
+ struct iovec fast_iov[UIO_FASTIOV];
+ struct iovec *iov = fast_iov;
+ struct iov_iter iter;
+
+ ret = import_iovec(rq_data_dir(req), ubuffer, bufflen,
+ UIO_FASTIOV, &iov, &iter);
+ if (ret < 0)
goto out;
+ ret = blk_rq_map_user_iov(q, req, NULL, &iter, GFP_KERNEL);
+ kfree(iov);To me some of this almost screams like lifting the vectored vs not to the block layer into a separate helper.
+ } + bio = req->bio; + if (ret) + goto out_unmap;
This seems incorrect, we don't need to unmap if blk_rq_map_user* failed.
+ if (bdev) + bio_set_dev(bio, bdev);
I think we can actually drop this now - bi_bdev should only be used by the non-passthrough path these days.
+ if (bdev && meta_buffer && meta_len) {
+ meta = nvme_add_user_metadata(bio, meta_buffer, meta_len,
+ meta_seed, req_op(req) == REQ_OP_DRV_OUT);
+ if (IS_ERR(meta)) {
+ ret = PTR_ERR(meta);
+ goto out_unmap;
}
+ req->cmd_flags |= REQ_INTEGRITY;
+ *metap = meta;And if we pass the request to nvme_add_user_metadata, that can set REQ_INTEGRITY. And we don't need this second helper at all.