diff options
Diffstat (limited to 'include/linux/fs.h')
| -rw-r--r-- | include/linux/fs.h | 47 |
1 files changed, 0 insertions, 47 deletions
diff --git a/include/linux/fs.h b/include/linux/fs.h index 46a74209917f..7a1b78ab7c15 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -151,58 +151,11 @@ typedef int (dio_iodone_t)(struct kiocb *iocb, loff_t offset, */ #define CHECK_IOVEC_ONLY -1 -/* - * The below are the various read and write flags that we support. Some of - * them include behavioral modifiers that send information down to the - * block layer and IO scheduler. They should be used along with a req_op. - * Terminology: - * - * The block layer uses device plugging to defer IO a little bit, in - * the hope that we will see more IO very shortly. This increases - * coalescing of adjacent IO and thus reduces the number of IOs we - * have to send to the device. It also allows for better queuing, - * if the IO isn't mergeable. If the caller is going to be waiting - * for the IO, then he must ensure that the device is unplugged so - * that the IO is dispatched to the driver. - * - * All IO is handled async in Linux. This is fine for background - * writes, but for reads or writes that someone waits for completion - * on, we want to notify the block layer and IO scheduler so that they - * know about it. That allows them to make better scheduling - * decisions. So when the below references 'sync' and 'async', it - * is referencing this priority hint. - * - * With that in mind, the available types are: - * - * READ A normal read operation. Device will be plugged. - * READ_SYNC A synchronous read. Device is not plugged, caller can - * immediately wait on this read without caring about - * unplugging. - * WRITE A normal async write. Device will be plugged. - * WRITE_SYNC Synchronous write. Identical to WRITE, but passes down - * the hint that someone will be waiting on this IO - * shortly. The write equivalent of READ_SYNC. - * WRITE_ODIRECT Special case write for O_DIRECT only. - * WRITE_FLUSH Like WRITE_SYNC but with preceding cache flush. - * WRITE_FUA Like WRITE_SYNC but data is guaranteed to be on - * non-volatile media on completion. - * WRITE_FLUSH_FUA Combination of WRITE_FLUSH and FUA. The IO is preceded - * by a cache flush and data is guaranteed to be on - * non-volatile media on completion. - * - */ #define RW_MASK REQ_OP_WRITE #define READ REQ_OP_READ #define WRITE REQ_OP_WRITE -#define READ_SYNC 0 -#define WRITE_SYNC REQ_SYNC -#define WRITE_ODIRECT (REQ_SYNC | REQ_IDLE) -#define WRITE_FLUSH REQ_PREFLUSH -#define WRITE_FUA REQ_FUA -#define WRITE_FLUSH_FUA (REQ_PREFLUSH | REQ_FUA) - /* * Attribute flags. These should be or-ed together to figure out what * has been changed! |