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Manfred Spraul
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. [[email protected]: really include the memset() into ipc_alloc_rcu()] Link: http://lkml.kernel.org/r/[email protected] Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Manfred Spraul <[email protected]> Cc: Davidlohr Bueso <[email protected]> Cc: Kees Cook <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
29 lines
548 B
C
29 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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