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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>
This commit is contained in:
Jens Axboe 2020-02-27 07:31:19 -07:00
parent bcda7baaa3
commit 4d954c258a
1 changed files with 97 additions and 14 deletions
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111
fs/io_uring.c
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@ -682,6 +682,7 @@ static const struct io_op_def io_op_defs[] = {
.needs_file = 1,
.unbound_nonreg_file = 1,
.pollin = 1,
.buffer_select = 1,
},
[IORING_OP_WRITEV] = {
.async_ctx = 1,
@ -1686,9 +1687,10 @@ static inline bool io_req_multi_free(struct req_batch *rb, struct io_kiocb *req)
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 @@ static struct io_buffer *io_buffer_select(struct io_kiocb *req, size_t *len,
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 @@ static ssize_t io_import_iovec(int rw, struct io_kiocb *req,
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 @@ static ssize_t io_import_iovec(int rw, struct io_kiocb *req,
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,