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io_uring: for requests that require async, force it
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Some requests require being run async as they do not support
non-blocking. Instead of trying to issue these requests, getting -EAGAIN
and then queueing them for async issue, rather just force async upfront.

Add WARN_ON_ONCE to make sure surprising code paths do not come up,
however in those cases the bug would end up being a blocking
io_uring_enter(2) which should not be critical.

Signed-off-by: Dylan Yudaken <dylany@meta.com>
Link: https://lore.kernel.org/r/20230127135227.3646353-3-dylany@meta.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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@axboe
Dylan Yudaken authored and axboe committed Jan 29, 2023
1 parent 6bb3085 commit aebb224
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Showing 7 changed files with 33 additions and 34 deletions.
4 changes: 2 additions & 2 deletions io_uring/advise.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -39,6 +39,7 @@ int io_madvise_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
ma->addr = READ_ONCE(sqe->addr);
ma->len = READ_ONCE(sqe->len);
ma->advice = READ_ONCE(sqe->fadvise_advice);
req->flags |= REQ_F_FORCE_ASYNC;
return 0;
#else
return -EOPNOTSUPP;
Expand All @@ -51,8 +52,7 @@ int io_madvise(struct io_kiocb *req, unsigned int issue_flags)
struct io_madvise *ma = io_kiocb_to_cmd(req, struct io_madvise);
int ret;

if (issue_flags & IO_URING_F_NONBLOCK)
return -EAGAIN;
WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);

ret = do_madvise(current->mm, ma->addr, ma->len, ma->advice);
io_req_set_res(req, ret, 0);
Expand Down
20 changes: 10 additions & 10 deletions io_uring/fs.c
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Original file line number Diff line number Diff line change
Expand Up @@ -74,6 +74,7 @@ int io_renameat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
}

req->flags |= REQ_F_NEED_CLEANUP;
req->flags |= REQ_F_FORCE_ASYNC;
return 0;
}

Expand All @@ -82,8 +83,7 @@ int io_renameat(struct io_kiocb *req, unsigned int issue_flags)
struct io_rename *ren = io_kiocb_to_cmd(req, struct io_rename);
int ret;

if (issue_flags & IO_URING_F_NONBLOCK)
return -EAGAIN;
WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);

ret = do_renameat2(ren->old_dfd, ren->oldpath, ren->new_dfd,
ren->newpath, ren->flags);
Expand Down Expand Up @@ -123,6 +123,7 @@ int io_unlinkat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
return PTR_ERR(un->filename);

req->flags |= REQ_F_NEED_CLEANUP;
req->flags |= REQ_F_FORCE_ASYNC;
return 0;
}

Expand All @@ -131,8 +132,7 @@ int io_unlinkat(struct io_kiocb *req, unsigned int issue_flags)
struct io_unlink *un = io_kiocb_to_cmd(req, struct io_unlink);
int ret;

if (issue_flags & IO_URING_F_NONBLOCK)
return -EAGAIN;
WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);

if (un->flags & AT_REMOVEDIR)
ret = do_rmdir(un->dfd, un->filename);
Expand Down Expand Up @@ -170,6 +170,7 @@ int io_mkdirat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
return PTR_ERR(mkd->filename);

req->flags |= REQ_F_NEED_CLEANUP;
req->flags |= REQ_F_FORCE_ASYNC;
return 0;
}

Expand All @@ -178,8 +179,7 @@ int io_mkdirat(struct io_kiocb *req, unsigned int issue_flags)
struct io_mkdir *mkd = io_kiocb_to_cmd(req, struct io_mkdir);
int ret;

if (issue_flags & IO_URING_F_NONBLOCK)
return -EAGAIN;
WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);

ret = do_mkdirat(mkd->dfd, mkd->filename, mkd->mode);

Expand Down Expand Up @@ -220,6 +220,7 @@ int io_symlinkat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
}

req->flags |= REQ_F_NEED_CLEANUP;
req->flags |= REQ_F_FORCE_ASYNC;
return 0;
}

Expand All @@ -228,8 +229,7 @@ int io_symlinkat(struct io_kiocb *req, unsigned int issue_flags)
struct io_link *sl = io_kiocb_to_cmd(req, struct io_link);
int ret;

if (issue_flags & IO_URING_F_NONBLOCK)
return -EAGAIN;
WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);

ret = do_symlinkat(sl->oldpath, sl->new_dfd, sl->newpath);

Expand Down Expand Up @@ -265,6 +265,7 @@ int io_linkat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
}

req->flags |= REQ_F_NEED_CLEANUP;
req->flags |= REQ_F_FORCE_ASYNC;
return 0;
}

Expand All @@ -273,8 +274,7 @@ int io_linkat(struct io_kiocb *req, unsigned int issue_flags)
struct io_link *lnk = io_kiocb_to_cmd(req, struct io_link);
int ret;

if (issue_flags & IO_URING_F_NONBLOCK)
return -EAGAIN;
WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);

ret = do_linkat(lnk->old_dfd, lnk->oldpath, lnk->new_dfd,
lnk->newpath, lnk->flags);
Expand Down
4 changes: 2 additions & 2 deletions io_uring/net.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -90,6 +90,7 @@ int io_shutdown_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
return -EINVAL;

shutdown->how = READ_ONCE(sqe->len);
req->flags |= REQ_F_FORCE_ASYNC;
return 0;
}

Expand All @@ -99,8 +100,7 @@ int io_shutdown(struct io_kiocb *req, unsigned int issue_flags)
struct socket *sock;
int ret;

if (issue_flags & IO_URING_F_NONBLOCK)
return -EAGAIN;
WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);

sock = sock_from_file(req->file);
if (unlikely(!sock))
Expand Down
7 changes: 3 additions & 4 deletions io_uring/splice.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -34,6 +34,7 @@ static int __io_splice_prep(struct io_kiocb *req,
if (unlikely(sp->flags & ~valid_flags))
return -EINVAL;
sp->splice_fd_in = READ_ONCE(sqe->splice_fd_in);
req->flags |= REQ_F_FORCE_ASYNC;
return 0;
}

Expand All @@ -52,8 +53,7 @@ int io_tee(struct io_kiocb *req, unsigned int issue_flags)
struct file *in;
long ret = 0;

if (issue_flags & IO_URING_F_NONBLOCK)
return -EAGAIN;
WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);

if (sp->flags & SPLICE_F_FD_IN_FIXED)
in = io_file_get_fixed(req, sp->splice_fd_in, issue_flags);
Expand Down Expand Up @@ -94,8 +94,7 @@ int io_splice(struct io_kiocb *req, unsigned int issue_flags)
struct file *in;
long ret = 0;

if (issue_flags & IO_URING_F_NONBLOCK)
return -EAGAIN;
WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);

if (sp->flags & SPLICE_F_FD_IN_FIXED)
in = io_file_get_fixed(req, sp->splice_fd_in, issue_flags);
Expand Down
4 changes: 2 additions & 2 deletions io_uring/statx.c
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Original file line number Diff line number Diff line change
Expand Up @@ -48,6 +48,7 @@ int io_statx_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
}

req->flags |= REQ_F_NEED_CLEANUP;
req->flags |= REQ_F_FORCE_ASYNC;
return 0;
}

Expand All @@ -56,8 +57,7 @@ int io_statx(struct io_kiocb *req, unsigned int issue_flags)
struct io_statx *sx = io_kiocb_to_cmd(req, struct io_statx);
int ret;

if (issue_flags & IO_URING_F_NONBLOCK)
return -EAGAIN;
WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);

ret = do_statx(sx->dfd, sx->filename, sx->flags, sx->mask, sx->buffer);
io_req_set_res(req, ret, 0);
Expand Down
14 changes: 8 additions & 6 deletions io_uring/sync.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -32,6 +32,8 @@ int io_sfr_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
sync->off = READ_ONCE(sqe->off);
sync->len = READ_ONCE(sqe->len);
sync->flags = READ_ONCE(sqe->sync_range_flags);
req->flags |= REQ_F_FORCE_ASYNC;

return 0;
}

Expand All @@ -41,8 +43,7 @@ int io_sync_file_range(struct io_kiocb *req, unsigned int issue_flags)
int ret;

/* sync_file_range always requires a blocking context */
if (issue_flags & IO_URING_F_NONBLOCK)
return -EAGAIN;
WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);

ret = sync_file_range(req->file, sync->off, sync->len, sync->flags);
io_req_set_res(req, ret, 0);
Expand All @@ -62,6 +63,7 @@ int io_fsync_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)

sync->off = READ_ONCE(sqe->off);
sync->len = READ_ONCE(sqe->len);
req->flags |= REQ_F_FORCE_ASYNC;
return 0;
}

Expand All @@ -72,8 +74,7 @@ int io_fsync(struct io_kiocb *req, unsigned int issue_flags)
int ret;

/* fsync always requires a blocking context */
if (issue_flags & IO_URING_F_NONBLOCK)
return -EAGAIN;
WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);

ret = vfs_fsync_range(req->file, sync->off, end > 0 ? end : LLONG_MAX,
sync->flags & IORING_FSYNC_DATASYNC);
Expand All @@ -91,6 +92,7 @@ int io_fallocate_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
sync->off = READ_ONCE(sqe->off);
sync->len = READ_ONCE(sqe->addr);
sync->mode = READ_ONCE(sqe->len);
req->flags |= REQ_F_FORCE_ASYNC;
return 0;
}

Expand All @@ -100,8 +102,8 @@ int io_fallocate(struct io_kiocb *req, unsigned int issue_flags)
int ret;

/* fallocate always requiring blocking context */
if (issue_flags & IO_URING_F_NONBLOCK)
return -EAGAIN;
WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);

ret = vfs_fallocate(req->file, sync->mode, sync->off, sync->len);
if (ret >= 0)
fsnotify_modify(req->file);
Expand Down
14 changes: 6 additions & 8 deletions io_uring/xattr.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -75,6 +75,7 @@ static int __io_getxattr_prep(struct io_kiocb *req,
}

req->flags |= REQ_F_NEED_CLEANUP;
req->flags |= REQ_F_FORCE_ASYNC;
return 0;
}

Expand Down Expand Up @@ -109,8 +110,7 @@ int io_fgetxattr(struct io_kiocb *req, unsigned int issue_flags)
struct io_xattr *ix = io_kiocb_to_cmd(req, struct io_xattr);
int ret;

if (issue_flags & IO_URING_F_NONBLOCK)
return -EAGAIN;
WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);

ret = do_getxattr(mnt_idmap(req->file->f_path.mnt),
req->file->f_path.dentry,
Expand All @@ -127,8 +127,7 @@ int io_getxattr(struct io_kiocb *req, unsigned int issue_flags)
struct path path;
int ret;

if (issue_flags & IO_URING_F_NONBLOCK)
return -EAGAIN;
WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);

retry:
ret = filename_lookup(AT_FDCWD, ix->filename, lookup_flags, &path, NULL);
Expand Down Expand Up @@ -174,6 +173,7 @@ static int __io_setxattr_prep(struct io_kiocb *req,
}

req->flags |= REQ_F_NEED_CLEANUP;
req->flags |= REQ_F_FORCE_ASYNC;
return 0;
}

Expand Down Expand Up @@ -222,8 +222,7 @@ int io_fsetxattr(struct io_kiocb *req, unsigned int issue_flags)
{
int ret;

if (issue_flags & IO_URING_F_NONBLOCK)
return -EAGAIN;
WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);

ret = __io_setxattr(req, issue_flags, &req->file->f_path);
io_xattr_finish(req, ret);
Expand All @@ -237,8 +236,7 @@ int io_setxattr(struct io_kiocb *req, unsigned int issue_flags)
struct path path;
int ret;

if (issue_flags & IO_URING_F_NONBLOCK)
return -EAGAIN;
WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);

retry:
ret = filename_lookup(AT_FDCWD, ix->filename, lookup_flags, &path, NULL);
Expand Down

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