Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-12-23 11:21:33 +00:00
Code Issues Packages Projects Releases Wiki Activity

scsi: rcu: Introduce rcu_swap_protected()

Browse Source 
A common pattern in RCU code is to assign a new value to an RCU pointer
after having read and stored the old value. Introduce a macro for this
pattern.

Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Cc: Shane M Seymour <shane.seymour@hpe.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Bart Van Assche 2017-08-29 08:50:11 -07:00 committed by Martin K. Petersen
parent fbf252335f
commit 26e3e3cb05
1 changed files with 16 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
include/linux/rcupdate.h
View File

@ -407,6 +407,22 @@ static inline void rcu_preempt_sleep_check(void) { }
_r_a_p__v; \
})
/**
* rcu_swap_protected() - swap an RCU and a regular pointer
* @rcu_ptr: RCU pointer
* @ptr: regular pointer
* @c: the conditions under which the dereference will take place
*
* Perform swap(@rcu_ptr, @ptr) where @rcu_ptr is an RCU-annotated pointer and
* @c is the argument that is passed to the rcu_dereference_protected() call
* used to read that pointer.
*/
#define rcu_swap_protected(rcu_ptr, ptr, c) do { \
typeof(ptr) __tmp = rcu_dereference_protected((rcu_ptr), (c)); \
rcu_assign_pointer((rcu_ptr), (ptr)); \
(ptr) = __tmp; \
} while (0)
/**
* rcu_access_pointer() - fetch RCU pointer with no dereferencing
* @p: The pointer to read