io_uring/io-wq: don't use static creds/mm assignments
We currently setup the io_wq with a static set of mm and creds. Even for
a single-use io-wq per io_uring, this is suboptimal as we have may have
multiple enters of the ring. For sharing the io-wq backend, it doesn't
work at all.
Switch to passing in the creds and mm when the work item is setup. This
means that async work is no longer deferred to the io_uring mm and creds,
it is done with the current mm and creds.
Flag this behavior with IORING_FEAT_CUR_PERSONALITY, so applications know
they can rely on the current personality (mm and creds) being the same
for direct issue and async issue.
Reviewed-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/fs/io-wq.h b/fs/io-wq.h
index 1cd039a..167316a 100644
--- a/fs/io-wq.h
+++ b/fs/io-wq.h
@@ -7,7 +7,6 @@ enum {
IO_WQ_WORK_CANCEL = 1,
IO_WQ_WORK_HAS_MM = 2,
IO_WQ_WORK_HASHED = 4,
- IO_WQ_WORK_NEEDS_USER = 8,
IO_WQ_WORK_NEEDS_FILES = 16,
IO_WQ_WORK_UNBOUND = 32,
IO_WQ_WORK_INTERNAL = 64,
@@ -74,6 +73,8 @@ struct io_wq_work {
};
void (*func)(struct io_wq_work **);
struct files_struct *files;
+ struct mm_struct *mm;
+ const struct cred *creds;
unsigned flags;
};
@@ -83,15 +84,15 @@ struct io_wq_work {
(work)->func = _func; \
(work)->flags = 0; \
(work)->files = NULL; \
+ (work)->mm = NULL; \
+ (work)->creds = NULL; \
} while (0) \
typedef void (get_work_fn)(struct io_wq_work *);
typedef void (put_work_fn)(struct io_wq_work *);
struct io_wq_data {
- struct mm_struct *mm;
struct user_struct *user;
- const struct cred *creds;
get_work_fn *get_work;
put_work_fn *put_work;