[PATCH 2/7] io_uring: add and use struct io_rw for read/writes

Jens Axboe
2019-12-20T17:47:48Z

Put the kiocb in struct io_rw, and add the addr/len for the request as
well. Use the kiocb->private field for the buffer index for fixed reads
and writes.

Any use of kiocb->ki_filp is flipped to req->file. It's the same thing,
and less confusing.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
fs/io_uring.c | 96 +++++++++++++++++++++++++++------------------------
1 file changed, 50 insertions(+), 46 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 7a23d2351be2..b5f91d21fd04 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -332,6 +332,13 @@ struct io_timeout {
int flags;
};

+struct io_rw {
+ /* NOTE: kiocb has the file as the first member, so don't do it here */
+ struct kiocb kiocb;
+ u64 addr;
+ u64 len;
+};
+
struct io_async_connect {
struct sockaddr_storage address;
};
@@ -369,7 +376,7 @@ struct io_async_ctx {
struct io_kiocb {
union {
struct file *file;
- struct kiocb rw;
+ struct io_rw rw;
struct io_poll_iocb poll;
struct io_accept accept;
struct io_sync sync;
@@ -1180,7 +1187,7 @@ static int io_do_iopoll(struct io_ring_ctx *ctx, unsigned int *nr_events,

ret = 0;
list_for_each_entry_safe(req, tmp, &ctx->poll_list, list) {
- struct kiocb *kiocb = &req->rw;
+ struct kiocb *kiocb = &req->rw.kiocb;

/*
* Move completed entries to our local list. If we find a
@@ -1335,7 +1342,7 @@ static inline void req_set_fail_links(struct io_kiocb *req)

static void io_complete_rw_common(struct kiocb *kiocb, long res)
{
- struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw);
+ struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb);

if (kiocb->ki_flags & IOCB_WRITE)
kiocb_end_write(req);
@@ -1347,7 +1354,7 @@ static void io_complete_rw_common(struct kiocb *kiocb, long res)

static void io_complete_rw(struct kiocb *kiocb, long res, long res2)
{
- struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw);
+ struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb);

io_complete_rw_common(kiocb, res);
io_put_req(req);
@@ -1355,7 +1362,7 @@ static void io_complete_rw(struct kiocb *kiocb, long res, long res2)

static struct io_kiocb *__io_complete_rw(struct kiocb *kiocb, long res)
{
- struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw);
+ struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb);
struct io_kiocb *nxt = NULL;

io_complete_rw_common(kiocb, res);
@@ -1366,7 +1373,7 @@ static struct io_kiocb *__io_complete_rw(struct kiocb *kiocb, long res)

static void io_complete_rw_iopoll(struct kiocb *kiocb, long res, long res2)
{
- struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw);
+ struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb);

if (kiocb->ki_flags & IOCB_WRITE)
kiocb_end_write(req);
@@ -1400,7 +1407,7 @@ static void io_iopoll_req_issued(struct io_kiocb *req)

list_req = list_first_entry(&ctx->poll_list, struct io_kiocb,
list);
- if (list_req->rw.ki_filp != req->rw.ki_filp)
+ if (list_req->file != req->file)
ctx->poll_multi_file = true;
}

@@ -1475,7 +1482,7 @@ static int io_prep_rw(struct io_kiocb *req, bool force_nonblock)
{
const struct io_uring_sqe *sqe = req->sqe;
struct io_ring_ctx *ctx = req->ctx;
- struct kiocb *kiocb = &req->rw;
+ struct kiocb *kiocb = &req->rw.kiocb;
unsigned ioprio;
int ret;

@@ -1524,6 +1531,12 @@ static int io_prep_rw(struct io_kiocb *req, bool force_nonblock)
return -EINVAL;
kiocb->ki_complete = io_complete_rw;
}
+
+ req->rw.addr = READ_ONCE(req->sqe->addr);
+ req->rw.len = READ_ONCE(req->sqe->len);
+ /* we own ->private, reuse it for the buffer index */
+ req->rw.kiocb.private = (void *) (unsigned long)
+ READ_ONCE(req->sqe->buf_index);
return 0;
}

@@ -1557,11 +1570,11 @@ static void kiocb_done(struct kiocb *kiocb, ssize_t ret, struct io_kiocb **nxt,
io_rw_done(kiocb, ret);
}

-static ssize_t io_import_fixed(struct io_ring_ctx *ctx, int rw,
- const struct io_uring_sqe *sqe,
+static ssize_t io_import_fixed(struct io_kiocb *req, int rw,
struct iov_iter *iter)
{
- size_t len = READ_ONCE(sqe->len);
+ struct io_ring_ctx *ctx = req->ctx;
+ size_t len = req->rw.len;
struct io_mapped_ubuf *imu;
unsigned index, buf_index;
size_t offset;
@@ -1571,13 +1584,13 @@ static ssize_t io_import_fixed(struct io_ring_ctx *ctx, int rw,
if (unlikely(!ctx->user_bufs))
return -EFAULT;

- buf_index = READ_ONCE(sqe->buf_index);
+ buf_index = (unsigned long) req->rw.kiocb.private;
if (unlikely(buf_index >= ctx->nr_user_bufs))
return -EFAULT;

index = array_index_nospec(buf_index, ctx->nr_user_bufs);
imu = &ctx->user_bufs[index];
- buf_addr = READ_ONCE(sqe->addr);
+ buf_addr = req->rw.addr;

/* overflow */
if (buf_addr + len < buf_addr)
@@ -1634,25 +1647,20 @@ static ssize_t io_import_fixed(struct io_ring_ctx *ctx, int rw,
static ssize_t io_import_iovec(int rw, struct io_kiocb *req,
struct iovec **iovec, struct iov_iter *iter)
{
- const struct io_uring_sqe *sqe = req->sqe;
- void __user *buf = u64_to_user_ptr(READ_ONCE(sqe->addr));
- size_t sqe_len = READ_ONCE(sqe->len);
+ void __user *buf = u64_to_user_ptr(req->rw.addr);
+ size_t sqe_len = req->rw.len;
u8 opcode;

- /*
- * We're reading ->opcode for the second time, but the first read
- * doesn't care whether it's _FIXED or not, so it doesn't matter
- * whether ->opcode changes concurrently. The first read does care
- * about whether it is a READ or a WRITE, so we don't trust this read
- * for that purpose and instead let the caller pass in the read/write
- * flag.
- */
opcode = req->opcode;
if (opcode == IORING_OP_READ_FIXED || opcode == IORING_OP_WRITE_FIXED) {
*iovec = NULL;
- return io_import_fixed(req->ctx, rw, sqe, iter);
+ return io_import_fixed(req, rw, iter);
}

+ /* buffer index only valid with fixed read/write */
+ if (req->rw.kiocb.private)
+ return -EINVAL;
+
if (req->io) {
struct io_async_rw *iorw = &req->io->rw;

@@ -1801,9 +1809,8 @@ static int io_read(struct io_kiocb *req, struct io_kiocb **nxt,
bool force_nonblock)
{
struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
- struct kiocb *kiocb = &req->rw;
+ struct kiocb *kiocb = &req->rw.kiocb;
struct iov_iter iter;
- struct file *file;
size_t iov_count;
ssize_t io_size, ret;

@@ -1819,9 +1826,8 @@ static int io_read(struct io_kiocb *req, struct io_kiocb **nxt,

/* Ensure we clear previously set non-block flag */
if (!force_nonblock)
- req->rw.ki_flags &= ~IOCB_NOWAIT;
+ req->rw.kiocb.ki_flags &= ~IOCB_NOWAIT;

- file = req->file;
io_size = ret;
if (req->flags & REQ_F_LINK)
req->result = io_size;
@@ -1830,20 +1836,20 @@ static int io_read(struct io_kiocb *req, struct io_kiocb **nxt,
* If the file doesn't support async, mark it as REQ_F_MUST_PUNT so
* we know to async punt it even if it was opened O_NONBLOCK
*/
- if (force_nonblock && !io_file_supports_async(file)) {
+ if (force_nonblock && !io_file_supports_async(req->file)) {
req->flags |= REQ_F_MUST_PUNT;
goto copy_iov;
}

iov_count = iov_iter_count(&iter);
- ret = rw_verify_area(READ, file, &kiocb->ki_pos, iov_count);
+ ret = rw_verify_area(READ, req->file, &kiocb->ki_pos, iov_count);
if (!ret) {
ssize_t ret2;

- if (file->f_op->read_iter)
- ret2 = call_read_iter(file, kiocb, &iter);
+ if (req->file->f_op->read_iter)
+ ret2 = call_read_iter(req->file, kiocb, &iter);
else
- ret2 = loop_rw_iter(READ, file, kiocb, &iter);
+ ret2 = loop_rw_iter(READ, req->file, kiocb, &iter);

/*
* In case of a short read, punt to async. This can happen
@@ -1894,9 +1900,8 @@ static int io_write(struct io_kiocb *req, struct io_kiocb **nxt,
bool force_nonblock)
{
struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
- struct kiocb *kiocb = &req->rw;
+ struct kiocb *kiocb = &req->rw.kiocb;
struct iov_iter iter;
- struct file *file;
size_t iov_count;
ssize_t ret, io_size;

@@ -1912,9 +1917,8 @@ static int io_write(struct io_kiocb *req, struct io_kiocb **nxt,

/* Ensure we clear previously set non-block flag */
if (!force_nonblock)
- req->rw.ki_flags &= ~IOCB_NOWAIT;
+ req->rw.kiocb.ki_flags &= ~IOCB_NOWAIT;

- file = kiocb->ki_filp;
io_size = ret;
if (req->flags & REQ_F_LINK)
req->result = io_size;
@@ -1934,7 +1938,7 @@ static int io_write(struct io_kiocb *req, struct io_kiocb **nxt,
goto copy_iov;

iov_count = iov_iter_count(&iter);
- ret = rw_verify_area(WRITE, file, &kiocb->ki_pos, iov_count);
+ ret = rw_verify_area(WRITE, req->file, &kiocb->ki_pos, iov_count);
if (!ret) {
ssize_t ret2;

@@ -1946,17 +1950,17 @@ static int io_write(struct io_kiocb *req, struct io_kiocb **nxt,
* we return to userspace.
*/
if (req->flags & REQ_F_ISREG) {
- __sb_start_write(file_inode(file)->i_sb,
+ __sb_start_write(file_inode(req->file)->i_sb,
SB_FREEZE_WRITE, true);
- __sb_writers_release(file_inode(file)->i_sb,
+ __sb_writers_release(file_inode(req->file)->i_sb,
SB_FREEZE_WRITE);
}
kiocb->ki_flags |= IOCB_WRITE;

- if (file->f_op->write_iter)
- ret2 = call_write_iter(file, kiocb, &iter);
+ if (req->file->f_op->write_iter)
+ ret2 = call_write_iter(req->file, kiocb, &iter);
else
- ret2 = loop_rw_iter(WRITE, file, kiocb, &iter);
+ ret2 = loop_rw_iter(WRITE, req->file, kiocb, &iter);
if (!force_nonblock || ret2 != -EAGAIN) {
kiocb_done(kiocb, ret2, nxt, req->in_async);
} else {
@@ -2036,7 +2040,7 @@ static void io_fsync_finish(struct io_wq_work **workptr)
if (io_req_cancelled(req))
return;

- ret = vfs_fsync_range(req->rw.ki_filp, req->sync.off,
+ ret = vfs_fsync_range(req->file, req->sync.off,
end > 0 ? end : LLONG_MAX,
req->sync.flags & IORING_FSYNC_DATASYNC);
if (ret < 0)
@@ -2102,7 +2106,7 @@ static void io_sync_file_range_finish(struct io_wq_work **workptr)
if (io_req_cancelled(req))
return;

- ret = sync_file_range(req->rw.ki_filp, req->sync.off, req->sync.len,
+ ret = sync_file_range(req->file, req->sync.off, req->sync.len,
req->sync.flags);
if (ret < 0)
req_set_fail_links(req);
--
2.24.1