io_uring: add IOSQE_BUFFER_SELECT support for IORING_OP_READV
This adds support for the vectored read. This is limited to supporting
just 1 segment in the iov, and is provided just for convenience for
applications that use IORING_OP_READV already.
The iov helpers will be used for IORING_OP_RECVMSG as well.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/fs/io_uring.c b/fs/io_uring.c
index a80b5c1..7c855a0 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -682,6 +682,7 @@
.needs_file = 1,
.unbound_nonreg_file = 1,
.pollin = 1,
+ .buffer_select = 1,
},
[IORING_OP_WRITEV] = {
.async_ctx = 1,
@@ -1686,9 +1687,10 @@
static int io_put_kbuf(struct io_kiocb *req)
{
- struct io_buffer *kbuf = (struct io_buffer *) req->rw.addr;
+ struct io_buffer *kbuf;
int cflags;
+ kbuf = (struct io_buffer *) (unsigned long) req->rw.addr;
cflags = kbuf->bid << IORING_CQE_BUFFER_SHIFT;
cflags |= IORING_CQE_F_BUFFER;
req->rw.addr = 0;
@@ -2242,12 +2244,95 @@
return kbuf;
}
+static void __user *io_rw_buffer_select(struct io_kiocb *req, size_t *len,
+ bool needs_lock)
+{
+ struct io_buffer *kbuf;
+ int bgid;
+
+ kbuf = (struct io_buffer *) (unsigned long) req->rw.addr;
+ bgid = (int) (unsigned long) req->rw.kiocb.private;
+ kbuf = io_buffer_select(req, len, bgid, kbuf, needs_lock);
+ if (IS_ERR(kbuf))
+ return kbuf;
+ req->rw.addr = (u64) (unsigned long) kbuf;
+ req->flags |= REQ_F_BUFFER_SELECTED;
+ return u64_to_user_ptr(kbuf->addr);
+}
+
+#ifdef CONFIG_COMPAT
+static ssize_t io_compat_import(struct io_kiocb *req, struct iovec *iov,
+ bool needs_lock)
+{
+ struct compat_iovec __user *uiov;
+ compat_ssize_t clen;
+ void __user *buf;
+ ssize_t len;
+
+ uiov = u64_to_user_ptr(req->rw.addr);
+ if (!access_ok(uiov, sizeof(*uiov)))
+ return -EFAULT;
+ if (__get_user(clen, &uiov->iov_len))
+ return -EFAULT;
+ if (clen < 0)
+ return -EINVAL;
+
+ len = clen;
+ buf = io_rw_buffer_select(req, &len, needs_lock);
+ if (IS_ERR(buf))
+ return PTR_ERR(buf);
+ iov[0].iov_base = buf;
+ iov[0].iov_len = (compat_size_t) len;
+ return 0;
+}
+#endif
+
+static ssize_t __io_iov_buffer_select(struct io_kiocb *req, struct iovec *iov,
+ bool needs_lock)
+{
+ struct iovec __user *uiov = u64_to_user_ptr(req->rw.addr);
+ void __user *buf;
+ ssize_t len;
+
+ if (copy_from_user(iov, uiov, sizeof(*uiov)))
+ return -EFAULT;
+
+ len = iov[0].iov_len;
+ if (len < 0)
+ return -EINVAL;
+ buf = io_rw_buffer_select(req, &len, needs_lock);
+ if (IS_ERR(buf))
+ return PTR_ERR(buf);
+ iov[0].iov_base = buf;
+ iov[0].iov_len = len;
+ return 0;
+}
+
+static ssize_t io_iov_buffer_select(struct io_kiocb *req, struct iovec *iov,
+ bool needs_lock)
+{
+ if (req->flags & REQ_F_BUFFER_SELECTED)
+ return 0;
+ if (!req->rw.len)
+ return 0;
+ else if (req->rw.len > 1)
+ return -EINVAL;
+
+#ifdef CONFIG_COMPAT
+ if (req->ctx->compat)
+ return io_compat_import(req, iov, needs_lock);
+#endif
+
+ return __io_iov_buffer_select(req, iov, needs_lock);
+}
+
static ssize_t io_import_iovec(int rw, struct io_kiocb *req,
struct iovec **iovec, struct iov_iter *iter,
bool needs_lock)
{
void __user *buf = u64_to_user_ptr(req->rw.addr);
size_t sqe_len = req->rw.len;
+ ssize_t ret;
u8 opcode;
opcode = req->opcode;
@@ -2261,22 +2346,12 @@
return -EINVAL;
if (opcode == IORING_OP_READ || opcode == IORING_OP_WRITE) {
- ssize_t ret;
-
if (req->flags & REQ_F_BUFFER_SELECT) {
- struct io_buffer *kbuf = (struct io_buffer *) req->rw.addr;
- int bgid;
-
- bgid = (int) (unsigned long) req->rw.kiocb.private;
- kbuf = io_buffer_select(req, &sqe_len, bgid, kbuf,
- needs_lock);
- if (IS_ERR(kbuf)) {
+ buf = io_rw_buffer_select(req, &sqe_len, needs_lock);
+ if (IS_ERR(buf)) {
*iovec = NULL;
- return PTR_ERR(kbuf);
+ return PTR_ERR(buf);
}
- req->rw.addr = (u64) kbuf;
- req->flags |= REQ_F_BUFFER_SELECTED;
- buf = u64_to_user_ptr(kbuf->addr);
}
ret = import_single_range(rw, buf, sqe_len, *iovec, iter);
@@ -2294,6 +2369,14 @@
return iorw->size;
}
+ if (req->flags & REQ_F_BUFFER_SELECT) {
+ ret = io_iov_buffer_select(req, *iovec, needs_lock);
+ if (!ret)
+ iov_iter_init(iter, rw, *iovec, 1, (*iovec)->iov_len);
+ *iovec = NULL;
+ return ret;
+ }
+
#ifdef CONFIG_COMPAT
if (req->ctx->compat)
return compat_import_iovec(rw, buf, sqe_len, UIO_FASTIOV,
