diff mbox series

[PATCHv5,08/11] nvme: map uring_cmd data even if address is 0

Message ID 20250224213116.3509093-9-kbusch@meta.com (mailing list archive)
State New
Headers show
Series ublk zero copy support | expand

Commit Message

Keith Busch Feb. 24, 2025, 9:31 p.m. UTC 
From: Xinyu Zhang <xizhang@purestorage.com>

When using kernel registered bvec fixed buffers, the "address" is
actually the offset into the bvec rather than userspace address.
Therefore it can be 0.
We can skip checking whether the address is NULL before mapping
uring_cmd data. Bad userspace address will be handled properly later when
the user buffer is imported.
With this patch, we will be able to use the kernel registered bvec fixed
buffers in io_uring NVMe passthru with ublk zero-copy support in
https://lore.kernel.org/io-uring/20250218224229.837848-1-kbusch@meta.com/T/#u.

Reviewed-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Xinyu Zhang <xizhang@purestorage.com>
---
 drivers/nvme/host/ioctl.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Ming Lei Feb. 25, 2025, 9:41 a.m. UTC | #1 
On Mon, Feb 24, 2025 at 01:31:13PM -0800, Keith Busch wrote:
> From: Xinyu Zhang <xizhang@purestorage.com>
> 
> When using kernel registered bvec fixed buffers, the "address" is
> actually the offset into the bvec rather than userspace address.
> Therefore it can be 0.
> We can skip checking whether the address is NULL before mapping
> uring_cmd data. Bad userspace address will be handled properly later when
> the user buffer is imported.
> With this patch, we will be able to use the kernel registered bvec fixed
> buffers in io_uring NVMe passthru with ublk zero-copy support in
> https://lore.kernel.org/io-uring/20250218224229.837848-1-kbusch@meta.com/T/#u.
> 
> Reviewed-by: Caleb Sander Mateos <csander@purestorage.com>
> Reviewed-by: Jens Axboe <axboe@kernel.dk>
> Reviewed-by: Keith Busch <kbusch@kernel.org>
> Signed-off-by: Xinyu Zhang <xizhang@purestorage.com>

Reviewed-by: Ming Lei <ming.lei@redhat.com>


Thanks,
Ming
diff mbox series

Patch

diff --git a/drivers/nvme/host/ioctl.c b/drivers/nvme/host/ioctl.c
index e0876bc9aacde..fe9fb80c6a144 100644
--- a/drivers/nvme/host/ioctl.c
+++ b/drivers/nvme/host/ioctl.c
@@ -513,7 +513,7 @@  static int nvme_uring_cmd_io(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
 		return PTR_ERR(req);
 	req->timeout = d.timeout_ms ? msecs_to_jiffies(d.timeout_ms) : 0;
 
-	if (d.addr && d.data_len) {
+	if (d.data_len) {
 		ret = nvme_map_user_request(req, d.addr,
 			d.data_len, nvme_to_user_ptr(d.metadata),
 			d.metadata_len, ioucmd, vec, issue_flags);