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Commit daf948c7 authored by Davidlohr Bueso's avatar Davidlohr Bueso Committed by Linus Torvalds
Browse files

ipc: delete seq_max field in struct ipc_ids 



This field is only used to reset the ids seq number if it exceeds the
smaller of INT_MAX/SEQ_MULTIPLIER and USHRT_MAX, and can therefore be
moved out of the structure and into its own macro.  Since each
ipc_namespace contains a table of 3 pointers to struct ipc_ids we can
save space in instruction text:

   text    data     bss     dec     hex filename
  56232    2348      24   58604    e4ec ipc/built-in.o
  56216    2348      24   58588    e4dc ipc/built-in.o-after

Signed-off-by: default avatarDavidlohr Bueso <davidlohr@hp.com>
Reviewed-by: default avatarJonathan Gonzalez <jgonzalez@linets.cl>
Cc: Aswin Chandramouleeswaran <aswin@hp.com>
Cc: Rik van Riel <riel@redhat.com>
Acked-by: default avatarManfred Spraul <manfred@colorfullife.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 8dc5cd04

include/linux/ipc_namespace.h

+0 −1
Original line number Diff line number Diff line
@@ -21,7 +21,6 @@ struct user_namespace; 
struct ipc_ids {

	int in_use;

	unsigned short seq;

	unsigned short seq_max;

	struct rw_semaphore rwsem;

	struct idr ipcs_idr;

	int next_id;

ipc/util.c

+2 −11
Original line number Diff line number Diff line
@@ -139,19 +139,10 @@ __initcall(ipc_init); 
 */

void ipc_init_ids(struct ipc_ids *ids)

{

	init_rwsem(&ids->rwsem);



	ids->in_use = 0;

	ids->seq = 0;

	ids->next_id = -1;

	{

		int seq_limit = INT_MAX/SEQ_MULTIPLIER;

		if (seq_limit > USHRT_MAX)

			ids->seq_max = USHRT_MAX;

		 else

			ids->seq_max = seq_limit;

	}



	init_rwsem(&ids->rwsem);

	idr_init(&ids->ipcs_idr);

}
@@ -304,7 +295,7 @@ int ipc_addid(struct ipc_ids *ids, struct kern_ipc_perm *new, int size) 


	if (next_id < 0) {

		new->seq = ids->seq++;

		if (ids->seq > ids->seq_max)

		if (ids->seq > IPCID_SEQ_MAX)

			ids->seq = 0;

	} else {

		new->seq = ipcid_to_seqx(next_id);

ipc/util.h

+1 −0
Original line number Diff line number Diff line
@@ -100,6 +100,7 @@ void __init ipc_init_proc_interface(const char *path, const char *header, 


#define ipcid_to_idx(id) ((id) % SEQ_MULTIPLIER)

#define ipcid_to_seqx(id) ((id) / SEQ_MULTIPLIER)

#define IPCID_SEQ_MAX min_t(int, INT_MAX/SEQ_MULTIPLIER, USHRT_MAX)



/* must be called with ids->rwsem acquired for writing */

int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int);