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dba4cdd39e
ipc has two management structures that exist for every id: - struct kern_ipc_perm, it contains e.g. the permissions. - struct ipc_rcu, it contains the rcu head for rcu handling and the refcount. The patch merges both structures. As a bonus, we may save one cacheline, because both structures are cacheline aligned. In addition, it reduces the number of casts, instead most codepaths can use container_of. To simplify code, the ipc_rcu_alloc initializes the allocation to 0. [manfred@colorfullife.com: really include the memset() into ipc_alloc_rcu()] Link: http://lkml.kernel.org/r/564f8612-0601-b267-514f-a9f650ec9b32@colorfullife.com Link: http://lkml.kernel.org/r/20170525185107.12869-3-manfred@colorfullife.com Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Kees Cook <keescook@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
28 lines
548 B
C
28 lines
548 B
C
#ifndef _LINUX_IPC_H
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#define _LINUX_IPC_H
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#include <linux/spinlock.h>
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#include <linux/uidgid.h>
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#include <uapi/linux/ipc.h>
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#define IPCMNI 32768 /* <= MAX_INT limit for ipc arrays (including sysctl changes) */
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/* used by in-kernel data structures */
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struct kern_ipc_perm {
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spinlock_t lock;
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bool deleted;
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int id;
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key_t key;
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kuid_t uid;
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kgid_t gid;
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kuid_t cuid;
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kgid_t cgid;
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umode_t mode;
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unsigned long seq;
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void *security;
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struct rcu_head rcu;
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atomic_t refcount;
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} ____cacheline_aligned_in_smp;
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#endif /* _LINUX_IPC_H */
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