The AIO interface is fairly complex because it tries to allow
filesystems to always work async and then wakeup a synchronous
caller through aio_complete. It turns out that basically no one
does this to avoid the complexity and context switches, with the
solve exception of fuse, so remove that possibility to simplify
the code.
XXX: fix up fuse.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
drivers/usb/gadget/function/f_fs.c | 4 ++--
fs/aio.c | 24 +-----------------------
fs/ecryptfs/file.c | 6 ------
fs/fuse/file.c | 7 +++++--
fs/read_write.c | 26 ++++++++------------------
include/linux/aio.h | 4 ----
net/socket.c | 9 +++------
7 files changed, 19 insertions(+), 61 deletions(-)
diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
index 63314ed..debd78b 100644
--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -969,7 +969,7 @@ static ssize_t ffs_epfile_aio_write(struct kiocb *kiocb,
if (unlikely(!io_data))
return -ENOMEM;
- io_data->aio = true;
+ io_data->aio = !is_sync_kiocb(kiocb);
io_data->read = false;
io_data->kiocb = kiocb;
io_data->iovec = iovec;
@@ -1005,7 +1005,7 @@ static ssize_t ffs_epfile_aio_read(struct kiocb *kiocb,
return -ENOMEM;
}
- io_data->aio = true;
+ io_data->aio = !is_sync_kiocb(kiocb);
io_data->read = true;
io_data->kiocb = kiocb;
io_data->iovec = iovec_copy;
diff --git a/fs/aio.c b/fs/aio.c
index 1b7893e..0ee25d6 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -791,22 +791,6 @@ static int kill_ioctx(struct mm_struct *mm, struct kioctx *ctx,
return 0;
}
-/* wait_on_sync_kiocb:
- * Waits on the given sync kiocb to complete.
- */
-ssize_t wait_on_sync_kiocb(struct kiocb *req)
-{
- while (!req->ki_ctx) {
- set_current_state(TASK_UNINTERRUPTIBLE);
- if (req->ki_ctx)
- break;
- io_schedule();
- }
- __set_current_state(TASK_RUNNING);
- return req->ki_user_data;
-}
-EXPORT_SYMBOL(wait_on_sync_kiocb);
-
/*
* exit_aio: called when the last user of mm goes away. At this point, there is
* no way for any new requests to be submited or any of the io_* syscalls to be
@@ -1038,13 +1022,7 @@ void aio_complete(struct kiocb *iocb, long res, long res2)
* ref, no other paths have a way to get another ref
* - the sync task helpfully left a reference to itself in the iocb
*/
- if (is_sync_kiocb(iocb)) {
- iocb->ki_user_data = res;
- smp_wmb();
- iocb->ki_ctx = ERR_PTR(-EXDEV);
- wake_up_process(iocb->ki_obj.tsk);
- return;
- }
+ BUG_ON(is_sync_kiocb(iocb));
if (iocb->ki_list.next) {
unsigned long flags;
diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c
index 6f4e659..a36da88 100644
--- a/fs/ecryptfs/file.c
+++ b/fs/ecryptfs/file.c
@@ -52,12 +52,6 @@ static ssize_t ecryptfs_read_update_atime(struct kiocb *iocb,
struct file *file = iocb->ki_filp;
rc = generic_file_read_iter(iocb, to);
- /*
- * Even though this is a async interface, we need to wait
- * for IO to finish to update atime
- */
- if (-EIOCBQUEUED == rc)
- rc = wait_on_sync_kiocb(iocb);
if (rc >= 0) {
path = ecryptfs_dentry_to_lower_path(file->f_path.dentry);
touch_atime(path);
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 760b2c5..9c27312 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -2841,8 +2841,10 @@ fuse_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter,
/*
* By default, we want to optimize all I/Os with async request
* submission to the client filesystem if supported.
+ *
+ * XXX: need to add back support for this mode..
*/
- io->async = async_dio;
+ io->async = async_dio && !is_sync_kiocb(iocb);
io->iocb = iocb;
/*
@@ -2865,7 +2867,8 @@ fuse_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter,
if (!is_sync_kiocb(iocb))
return -EIOCBQUEUED;
- ret = wait_on_sync_kiocb(iocb);
+ // XXX: need fuse specific replacement
+// ret = wait_on_sync_kiocb(iocb);
} else {
kfree(io);
}
diff --git a/fs/read_write.c b/fs/read_write.c
index ab4f26a..adab608 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -347,9 +347,7 @@ ssize_t vfs_iter_read(struct file *file, struct iov_iter *iter, loff_t *ppos)
iter->type |= READ;
ret = file->f_op->read_iter(&kiocb, iter);
- if (ret == -EIOCBQUEUED)
- ret = wait_on_sync_kiocb(&kiocb);
-
+ BUG_ON(ret == -EIOCBQUEUED);
if (ret > 0)
*ppos = kiocb.ki_pos;
return ret;
@@ -370,9 +368,7 @@ ssize_t vfs_iter_write(struct file *file, struct iov_iter *iter, loff_t *ppos)
iter->type |= WRITE;
ret = file->f_op->write_iter(&kiocb, iter);
- if (ret == -EIOCBQUEUED)
- ret = wait_on_sync_kiocb(&kiocb);
-
+ BUG_ON(ret == -EIOCBQUEUED);
if (ret > 0)
*ppos = kiocb.ki_pos;
return ret;
@@ -429,8 +425,7 @@ ssize_t do_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *pp
kiocb.ki_nbytes = len;
ret = filp->f_op->aio_read(&kiocb, &iov, 1, kiocb.ki_pos);
- if (-EIOCBQUEUED == ret)
- ret = wait_on_sync_kiocb(&kiocb);
+ BUG_ON(ret == -EIOCBQUEUED);
*ppos = kiocb.ki_pos;
return ret;
}
@@ -450,8 +445,7 @@ ssize_t new_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *p
iov_iter_init(&iter, READ, &iov, 1, len);
ret = filp->f_op->read_iter(&kiocb, &iter);
- if (-EIOCBQUEUED == ret)
- ret = wait_on_sync_kiocb(&kiocb);
+ BUG_ON(ret == -EIOCBQUEUED);
*ppos = kiocb.ki_pos;
return ret;
}
@@ -513,8 +507,7 @@ ssize_t do_sync_write(struct file *filp, const char __user *buf, size_t len, lof
kiocb.ki_nbytes = len;
ret = filp->f_op->aio_write(&kiocb, &iov, 1, kiocb.ki_pos);
- if (-EIOCBQUEUED == ret)
- ret = wait_on_sync_kiocb(&kiocb);
+ BUG_ON(ret == -EIOCBQUEUED);
*ppos = kiocb.ki_pos;
return ret;
}
@@ -534,8 +527,7 @@ ssize_t new_sync_write(struct file *filp, const char __user *buf, size_t len, lo
iov_iter_init(&iter, WRITE, &iov, 1, len);
ret = filp->f_op->write_iter(&kiocb, &iter);
- if (-EIOCBQUEUED == ret)
- ret = wait_on_sync_kiocb(&kiocb);
+ BUG_ON(ret == -EIOCBQUEUED);
*ppos = kiocb.ki_pos;
return ret;
}
@@ -723,8 +715,7 @@ static ssize_t do_iter_readv_writev(struct file *filp, int rw, const struct iove
iov_iter_init(&iter, rw, iov, nr_segs, len);
ret = fn(&kiocb, &iter);
- if (ret == -EIOCBQUEUED)
- ret = wait_on_sync_kiocb(&kiocb);
+ BUG_ON(ret == -EIOCBQUEUED);
*ppos = kiocb.ki_pos;
return ret;
}
@@ -740,8 +731,7 @@ static ssize_t do_sync_readv_writev(struct file *filp, const struct iovec *iov,
kiocb.ki_nbytes = len;
ret = fn(&kiocb, iov, nr_segs, kiocb.ki_pos);
- if (ret == -EIOCBQUEUED)
- ret = wait_on_sync_kiocb(&kiocb);
+ BUG_ON(ret == -EIOCBQUEUED);
*ppos = kiocb.ki_pos;
return ret;
}
diff --git a/include/linux/aio.h b/include/linux/aio.h
index d9c92da..57c86c0 100644
--- a/include/linux/aio.h
+++ b/include/linux/aio.h
@@ -37,7 +37,6 @@ struct kiocb {
union {
void __user *user;
- struct task_struct *tsk;
} ki_obj;
__u64 ki_user_data; /* user's data for completion */
@@ -64,13 +63,11 @@ static inline void init_sync_kiocb(struct kiocb *kiocb, struct file *filp)
*kiocb = (struct kiocb) {
.ki_ctx = NULL,
.ki_filp = filp,
- .ki_obj.tsk = current,
};
}
/* prototypes */
#ifdef CONFIG_AIO
-extern ssize_t wait_on_sync_kiocb(struct kiocb *iocb);
extern void aio_complete(struct kiocb *iocb, long res, long res2);
struct mm_struct;
extern void exit_aio(struct mm_struct *mm);
@@ -78,7 +75,6 @@ extern long do_io_submit(aio_context_t ctx_id, long nr,
struct iocb __user *__user *iocbpp, bool compat);
void kiocb_set_cancel_fn(struct kiocb *req, kiocb_cancel_fn *cancel);
#else
-static inline ssize_t wait_on_sync_kiocb(struct kiocb *iocb) { return 0; }
static inline void aio_complete(struct kiocb *iocb, long res, long res2) { }
struct mm_struct;
static inline void exit_aio(struct mm_struct *mm) { }
diff --git a/net/socket.c b/net/socket.c
index a2c33a4..4032931 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -642,8 +642,7 @@ static int do_sock_sendmsg(struct socket *sock, struct msghdr *msg,
iocb.private = &siocb;
ret = nosec ? __sock_sendmsg_nosec(&iocb, sock, msg, size) :
__sock_sendmsg(&iocb, sock, msg, size);
- if (-EIOCBQUEUED == ret)
- ret = wait_on_sync_kiocb(&iocb);
+ BUG_ON(-EIOCBQUEUED == ret);
return ret;
}
@@ -785,8 +784,7 @@ int sock_recvmsg(struct socket *sock, struct msghdr *msg,
init_sync_kiocb(&iocb, NULL);
iocb.private = &siocb;
ret = __sock_recvmsg(&iocb, sock, msg, size, flags);
- if (-EIOCBQUEUED == ret)
- ret = wait_on_sync_kiocb(&iocb);
+ BUG_ON(-EIOCBQUEUED == ret);
return ret;
}
EXPORT_SYMBOL(sock_recvmsg);
@@ -801,8 +799,7 @@ static int sock_recvmsg_nosec(struct socket *sock, struct msghdr *msg,
init_sync_kiocb(&iocb, NULL);
iocb.private = &siocb;
ret = __sock_recvmsg_nosec(&iocb, sock, msg, size, flags);
- if (-EIOCBQUEUED == ret)
- ret = wait_on_sync_kiocb(&iocb);
+ BUG_ON(-EIOCBQUEUED == ret);
return ret;
}
--
1.9.1
--
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