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block: add a flag to identify PM request

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Add a flag REQ_PM to identify the request is PM related, such requests
will not change the device request queue's runtime status. It is
intended to be used in driver's runtime PM callback, so that driver can
perform some IO to the device there with the queue's runtime status
unaffected. e.g. in SCSI disk's runtime suspend callback, the disk will
be put into stopped power state, and this require sending a command to
the device. Such command processing should not change the disk's runtime
status.

Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Lin Ming 2013-03-23 11:42:24 +08:00 committed by Jens Axboe
parent a937536b86
commit 6631127469
1 changed files with 2 additions and 0 deletions

2
include/linux/blk_types.h

@ -175,6 +175,7 @@ enum rq_flag_bits {
__REQ_IO_STAT, /* account I/O stat */
__REQ_MIXED_MERGE, /* merge of different types, fail separately */
__REQ_KERNEL, /* direct IO to kernel pages */
__REQ_PM, /* runtime pm request */
__REQ_NR_BITS, /* stops here */
};
@ -223,5 +224,6 @@ enum rq_flag_bits {
#define REQ_MIXED_MERGE (1 << __REQ_MIXED_MERGE)
#define REQ_SECURE (1 << __REQ_SECURE)
#define REQ_KERNEL (1 << __REQ_KERNEL)
#define REQ_PM (1 << __REQ_PM)
#endif /* __LINUX_BLK_TYPES_H */