fs: Add aio iopriority support

This is the per-I/O equivalent of the ioprio_set system call.

When IOCB_FLAG_IOPRIO is set on the iocb aio_flags field, then we set the
newly added kiocb ki_ioprio field to the value in the iocb aio_reqprio field.

This patch depends on block: add ioprio_check_cap function.

Signed-off-by: Adam Manzanares <adam.manzanares@wdc.com>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

2 files changed, 4 insertions, 0 deletions

diff --git a/include/linux/fs.h b/include/linux/fs.h
index b432fc3feb93..eef9334b26d1 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -36,6 +36,7 @@
 #include <linux/delayed_call.h>
 #include <linux/uuid.h>
 #include <linux/errseq.h>
+#include <linux/ioprio.h>
 
 #include <asm/byteorder.h>
 #include <uapi/linux/fs.h>
@@ -300,6 +301,7 @@ struct kiocb {
         void                    *private;
         int                     ki_flags;
         u16                     ki_hint;
+        u16                     ki_ioprio; /* See linux/ioprio.h */
 } __randomize_layout;
 
 static inline bool is_sync_kiocb(struct kiocb *kiocb)
@@ -1944,6 +1946,7 @@ static inline void init_sync_kiocb(struct kiocb *kiocb, struct file *filp)
                 .ki_filp = filp,
                 .ki_flags = iocb_flags(filp),
                 .ki_hint = ki_hint_validate(file_write_hint(filp)),
+                .ki_ioprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_NONE, 0),
         };
 }
 
diff --git a/include/uapi/linux/aio_abi.h b/include/uapi/linux/aio_abi.h
index ed0185945bb2..75846164290e 100644
--- a/include/uapi/linux/aio_abi.h
+++ b/include/uapi/linux/aio_abi.h
@@ -53,6 +53,7 @@ enum {
  *                   is valid.
  */
 #define IOCB_FLAG_RESFD         (1 << 0)
+#define IOCB_FLAG_IOPRIO        (1 << 1)
 
 /* read() from /dev/aio returns these structures. */
 struct io_event {