ipc: delete seq_max field in struct ipc_ids (daf948c7) · Commits · 戴 / test

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:

Davidlohr Bueso <davidlohr@hp.com> Reviewed-by:

Jonathan Gonzalez <jgonzalez@linets.cl> Cc: Aswin Chandramouleeswaran <aswin@hp.com> Cc: Rik van Riel <riel@redhat.com> Acked-by:

Manfred Spraul <manfred@colorfullife.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

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);

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