io_uring/mock: support for async read/write

Let the user to specify a delay to read/write request. io_uring will
start a timer, return -EIOCBQUEUED and complete the request
asynchronously after the delay pass.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/38f9d2e143fda8522c90a724b74630e68f9bbd16.1750599274.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/include/uapi/linux/io_uring/mock_file.h b/include/uapi/linux/io_uring/mock_file.h
index 125949d2b5cea0aec2046956ad2d6b61c10c9ed6..c8fa77e39c681667aa5b5b0b5872de6debfd08af 100644 (file)
--- a/include/uapi/linux/io_uring/mock_file.h
+++ b/include/uapi/linux/io_uring/mock_file.h
@@ -7,6 +7,7 @@ enum {
        IORING_MOCK_FEAT_CMD_COPY,
        IORING_MOCK_FEAT_RW_ZERO,
        IORING_MOCK_FEAT_RW_NOWAIT,
+       IORING_MOCK_FEAT_RW_ASYNC,
 
        IORING_MOCK_FEAT_END,
 };
@@ -24,7 +25,8 @@ struct io_uring_mock_create {
        __u32           out_fd;
        __u32           flags;
        __u64           file_size;
-       __u64           __resv[14];
+       __u64           rw_delay_ns;
+       __u64           __resv[13];
 };
 
 enum {

diff --git a/io_uring/mock_file.c b/io_uring/mock_file.c
index 0eb1d3bd63681aeabf6f11d6057ace87d360430f..ed6a5505763e9bbcf7287f24eaa7d9bdb11974f2 100644 (file)
--- a/io_uring/mock_file.c
+++ b/io_uring/mock_file.c
@@ -4,13 +4,22 @@
 #include <linux/miscdevice.h>
 #include <linux/module.h>
 #include <linux/anon_inodes.h>
+#include <linux/ktime.h>
+#include <linux/hrtimer.h>
 
 #include <linux/io_uring/cmd.h>
 #include <linux/io_uring_types.h>
 #include <uapi/linux/io_uring/mock_file.h>
 
+struct io_mock_iocb {
+       struct kiocb            *iocb;
+       struct hrtimer          timer;
+       int                     res;
+};
+
 struct io_mock_file {
-       size_t size;
+       size_t                  size;
+       u64                     rw_delay_ns;
 };
 
 #define IO_VALID_COPY_CMD_FLAGS                IORING_MOCK_COPY_FROM
@@ -86,14 +95,48 @@ static int io_mock_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags)
        return -ENOTSUPP;
 }
 
+static enum hrtimer_restart io_mock_rw_timer_expired(struct hrtimer *timer)
+{
+       struct io_mock_iocb *mio = container_of(timer, struct io_mock_iocb, timer);
+       struct kiocb *iocb = mio->iocb;
+
+       WRITE_ONCE(iocb->private, NULL);
+       iocb->ki_complete(iocb, mio->res);
+       kfree(mio);
+       return HRTIMER_NORESTART;
+}
+
+static ssize_t io_mock_delay_rw(struct kiocb *iocb, size_t len)
+{
+       struct io_mock_file *mf = iocb->ki_filp->private_data;
+       struct io_mock_iocb *mio;
+
+       mio = kzalloc(sizeof(*mio), GFP_KERNEL);
+       if (!mio)
+               return -ENOMEM;
+
+       mio->iocb = iocb;
+       mio->res = len;
+       hrtimer_setup(&mio->timer, io_mock_rw_timer_expired,
+                     CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+       hrtimer_start(&mio->timer, ns_to_ktime(mf->rw_delay_ns),
+                     HRTIMER_MODE_REL);
+       return -EIOCBQUEUED;
+}
+
 static ssize_t io_mock_read_iter(struct kiocb *iocb, struct iov_iter *to)
 {
        struct io_mock_file *mf = iocb->ki_filp->private_data;
        size_t len = iov_iter_count(to);
+       size_t nr_zeroed;
 
        if (iocb->ki_pos + len > mf->size)
                return -EINVAL;
-       return iov_iter_zero(len, to);
+       nr_zeroed = iov_iter_zero(len, to);
+       if (!mf->rw_delay_ns || nr_zeroed != len)
+               return nr_zeroed;
+
+       return io_mock_delay_rw(iocb, len);
 }
 
 static ssize_t io_mock_write_iter(struct kiocb *iocb, struct iov_iter *from)
@@ -103,8 +146,12 @@ static ssize_t io_mock_write_iter(struct kiocb *iocb, struct iov_iter *from)
 
        if (iocb->ki_pos + len > mf->size)
                return -EINVAL;
-       iov_iter_advance(from, len);
-       return len;
+       if (!mf->rw_delay_ns) {
+               iov_iter_advance(from, len);
+               return len;
+       }
+
+       return io_mock_delay_rw(iocb, len);
 }
 
 static loff_t io_mock_llseek(struct file *file, loff_t offset, int whence)
@@ -165,6 +212,9 @@ static int io_create_mock_file(struct io_uring_cmd *cmd, unsigned int issue_flag
                return -EINVAL;
        if (mc.file_size > SZ_1G)
                return -EINVAL;
+       if (mc.rw_delay_ns > NSEC_PER_SEC)
+               return -EINVAL;
+
        mf = kzalloc(sizeof(*mf), GFP_KERNEL_ACCOUNT);
        if (!mf)
                return -ENOMEM;
@@ -174,6 +224,7 @@ static int io_create_mock_file(struct io_uring_cmd *cmd, unsigned int issue_flag
                goto fail;
 
        mf->size = mc.file_size;
+       mf->rw_delay_ns = mc.rw_delay_ns;
        file = anon_inode_create_getfile("[io_uring_mock]", &io_mock_fops,
                                         mf, O_RDWR | O_CLOEXEC, NULL);
        if (IS_ERR(file)) {