diff mbox series

[1/4] iov: add import_ubuf()

Message ID 20221107175610.349807-2-kbusch@meta.com (mailing list archive)
State New
Headers show
Series io_uring: use ITER_UBUF | expand

Commit Message

Keith Busch Nov. 7, 2022, 5:56 p.m. UTC 
From: Jens Axboe <axboe@kernel.dk>

Like import_single_range(), but for ITER_UBUF.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 include/linux/uio.h |  1 +
 lib/iov_iter.c      | 11 +++++++++++
 2 files changed, 12 insertions(+)

Comments

Christoph Hellwig Nov. 8, 2022, 6:55 a.m. UTC | #1 
On Mon, Nov 07, 2022 at 09:56:07AM -0800, Keith Busch wrote:
> From: Jens Axboe <axboe@kernel.dk>
> 
> Like import_single_range(), but for ITER_UBUF.

So what is the argument for not simplify switching
import_single_range to always do a ITER_UBUF?  Maybe there is a reason
against that, but it should be clearly stated here.

> 
> Signed-off-by: Jens Axboe <axboe@kernel.dk>

Now that this went through your hands it also needs your signoff.
Keith Busch Nov. 8, 2022, 4:05 p.m. UTC | #2 
On Mon, Nov 07, 2022 at 10:55:49PM -0800, Christoph Hellwig wrote:
> On Mon, Nov 07, 2022 at 09:56:07AM -0800, Keith Busch wrote:
> > From: Jens Axboe <axboe@kernel.dk>
> > 
> > Like import_single_range(), but for ITER_UBUF.
> 
> So what is the argument for not simplify switching
> import_single_range to always do a ITER_UBUF?  Maybe there is a reason
> against that, but it should be clearly stated here.

That may be a good idea if everyone uses the more efficient iter, but I
thought it'd be safer to keep them separate. There are just a few
import_single_range() users that expect the result be ITER_IOVEC. It
will take some extra time on my side to make sure that kind of change
won't break anything.
diff mbox series

Patch

diff --git a/include/linux/uio.h b/include/linux/uio.h
index 2e3134b14ffd..27575495c006 100644
--- a/include/linux/uio.h
+++ b/include/linux/uio.h
@@ -337,6 +337,7 @@  ssize_t __import_iovec(int type, const struct iovec __user *uvec,
 		 struct iov_iter *i, bool compat);
 int import_single_range(int type, void __user *buf, size_t len,
 		 struct iovec *iov, struct iov_iter *i);
+int import_ubuf(int type, void __user *buf, size_t len, struct iov_iter *i);
 
 static inline void iov_iter_ubuf(struct iov_iter *i, unsigned int direction,
 			void __user *buf, size_t count)
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index c3ca28ca68a6..07adf18e5e40 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -1855,6 +1855,17 @@  int import_single_range(int rw, void __user *buf, size_t len,
 }
 EXPORT_SYMBOL(import_single_range);
 
+int import_ubuf(int rw, void __user *buf, size_t len, struct iov_iter *i)
+{
+	if (len > MAX_RW_COUNT)
+		len = MAX_RW_COUNT;
+	if (unlikely(!access_ok(buf, len)))
+		return -EFAULT;
+
+	iov_iter_ubuf(i, rw, buf, len);
+	return 0;
+}
+
 /**
  * iov_iter_restore() - Restore a &struct iov_iter to the same state as when
  *     iov_iter_save_state() was called.