fork: move copy_io to block/blk-ioc.c

Move the copying of the I/O context to the block layer as that is where
we can use the proper low-level interfaces.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211126115817.2087431-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-ioc.c b/block/blk-ioc.c
index 70c99e85aee5041a3170e03f8fbf27de50c422f5..3b31cfad4b75bfe08c0a555d4cc0bcf98a77154d 100644 (file)
--- a/block/blk-ioc.c
+++ b/block/blk-ioc.c
@@ -322,6 +322,33 @@ struct io_context *get_task_io_context(struct task_struct *task,
        return NULL;
 }
 
+int __copy_io(unsigned long clone_flags, struct task_struct *tsk)
+{
+       struct io_context *ioc = current->io_context;
+       struct io_context *new_ioc;
+
+       /*
+        * Share io context with parent, if CLONE_IO is set
+        */
+       if (clone_flags & CLONE_IO) {
+               get_io_context_active(ioc);
+
+               WARN_ON_ONCE(atomic_read(&ioc->nr_tasks) <= 0);
+               atomic_inc(&ioc->nr_tasks);
+
+               tsk->io_context = ioc;
+       } else if (ioprio_valid(ioc->ioprio)) {
+               new_ioc = get_task_io_context(tsk, GFP_KERNEL, NUMA_NO_NODE);
+               if (unlikely(!new_ioc))
+                       return -ENOMEM;
+
+               new_ioc->ioprio = ioc->ioprio;
+               put_io_context(new_ioc);
+       }
+
+       return 0;
+}
+
 /**
  * ioc_lookup_icq - lookup io_cq from ioc
  * @ioc: the associated io_context

diff --git a/include/linux/iocontext.h b/include/linux/iocontext.h
index 0a9dc40b7be84e67045474b17d82ae270fec6abe..bcd47d104d8e67e054a8b630ad7442d0d04577c2 100644 (file)
--- a/include/linux/iocontext.h
+++ b/include/linux/iocontext.h
@@ -129,14 +129,6 @@ static inline void get_io_context_active(struct io_context *ioc)
        atomic_inc(&ioc->active_ref);
 }
 
-static inline void ioc_task_link(struct io_context *ioc)
-{
-       get_io_context_active(ioc);
-
-       WARN_ON_ONCE(atomic_read(&ioc->nr_tasks) <= 0);
-       atomic_inc(&ioc->nr_tasks);
-}
-
 struct task_struct;
 #ifdef CONFIG_BLOCK
 void put_io_context(struct io_context *ioc);
@@ -144,10 +136,21 @@ void put_io_context_active(struct io_context *ioc);
 void exit_io_context(struct task_struct *task);
 struct io_context *get_task_io_context(struct task_struct *task,
                                       gfp_t gfp_flags, int node);
+int __copy_io(unsigned long clone_flags, struct task_struct *tsk);
+static inline int copy_io(unsigned long clone_flags, struct task_struct *tsk)
+{
+       if (!current->io_context)
+               return 0;
+       return __copy_io(clone_flags, tsk);
+}
 #else
 struct io_context;
 static inline void put_io_context(struct io_context *ioc) { }
 static inline void exit_io_context(struct task_struct *task) { }
-#endif
+static inline int copy_io(unsigned long clone_flags, struct task_struct *tsk)
+{
+       return 0;
+}
+#endif /* CONFIG_BLOCK */
 
-#endif
+#endif /* IOCONTEXT_H */

diff --git a/kernel/fork.c b/kernel/fork.c
index 3244cc56b697d7e3a5b3a87d1ed580fb64db1954..3161d7980155e08ead8bf4c401ae8e5ec4d08a21 100644 (file)
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1556,32 +1556,6 @@ out:
        return error;
 }
 
-static int copy_io(unsigned long clone_flags, struct task_struct *tsk)
-{
-#ifdef CONFIG_BLOCK
-       struct io_context *ioc = current->io_context;
-       struct io_context *new_ioc;
-
-       if (!ioc)
-               return 0;
-       /*
-        * Share io context with parent, if CLONE_IO is set
-        */
-       if (clone_flags & CLONE_IO) {
-               ioc_task_link(ioc);
-               tsk->io_context = ioc;
-       } else if (ioprio_valid(ioc->ioprio)) {
-               new_ioc = get_task_io_context(tsk, GFP_KERNEL, NUMA_NO_NODE);
-               if (unlikely(!new_ioc))
-                       return -ENOMEM;
-
-               new_ioc->ioprio = ioc->ioprio;
-               put_io_context(new_ioc);
-       }
-#endif
-       return 0;
-}
-
 static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk)
 {
        struct sighand_struct *sig;