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98f06978ff
At present, a built-in spufs will not use the spufs_calls callbacks, but directly call sys_spu_create. This saves us an indirect branch, but means we have duplicated functions - one for CONFIG_SPU_FS=y and one for =m. This change unifies the spufs syscall path, and provides access to the spufs_calls structure through a get/put pair. At present, the only user of the spufs_calls structure is spu_syscalls.c, but this will facilitate adding the coredump calls later. Everyone likes numbers, right? Here's a before/after comparison with CONFIG_SPU_FS=y, doing spu_create(); close(); 64k times. Before: [jk@cell ~]$ time ./spu_create performing 65536 spu_create calls real 0m24.075s user 0m0.146s sys 0m23.925s After: [jk@cell ~]$ time ./spu_create performing 65536 spu_create calls real 0m24.777s user 0m0.141s sys 0m24.631s So, we're adding around 11us per syscall, at the benefit of having only one syscall path. Signed-off-by: Jeremy Kerr <jk@ozlabs.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
131 lines
3.1 KiB
C
131 lines
3.1 KiB
C
/*
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* SPU file system -- system call stubs
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*
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* (C) Copyright IBM Deutschland Entwicklung GmbH 2005
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*
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* Author: Arnd Bergmann <arndb@de.ibm.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <linux/file.h>
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#include <linux/module.h>
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#include <linux/syscalls.h>
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#include <linux/rcupdate.h>
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#include <asm/spu.h>
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/* protected by rcu */
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static struct spufs_calls *spufs_calls;
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#ifdef CONFIG_SPU_FS_MODULE
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static inline struct spufs_calls *spufs_calls_get(void)
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{
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struct spufs_calls *calls = NULL;
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rcu_read_lock();
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calls = rcu_dereference(spufs_calls);
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if (calls && !try_module_get(calls->owner))
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calls = NULL;
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rcu_read_unlock();
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return calls;
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}
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static inline void spufs_calls_put(struct spufs_calls *calls)
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{
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BUG_ON(calls != spufs_calls);
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/* we don't need to rcu this, as we hold a reference to the module */
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module_put(spufs_calls->owner);
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}
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#else /* !defined CONFIG_SPU_FS_MODULE */
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static inline struct spufs_calls *spufs_calls_get(void)
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{
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return spufs_calls;
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}
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static inline void spufs_calls_put(struct spufs_calls *calls) { }
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#endif /* CONFIG_SPU_FS_MODULE */
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asmlinkage long sys_spu_create(const char __user *name,
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unsigned int flags, mode_t mode, int neighbor_fd)
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{
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long ret;
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struct file *neighbor;
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int fput_needed;
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struct spufs_calls *calls;
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calls = spufs_calls_get();
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if (!calls)
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return -ENOSYS;
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if (flags & SPU_CREATE_AFFINITY_SPU) {
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ret = -EBADF;
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neighbor = fget_light(neighbor_fd, &fput_needed);
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if (neighbor) {
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ret = calls->create_thread(name, flags, mode, neighbor);
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fput_light(neighbor, fput_needed);
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}
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} else
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ret = calls->create_thread(name, flags, mode, NULL);
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spufs_calls_put(calls);
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return ret;
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}
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asmlinkage long sys_spu_run(int fd, __u32 __user *unpc, __u32 __user *ustatus)
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{
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long ret;
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struct file *filp;
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int fput_needed;
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struct spufs_calls *calls;
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calls = spufs_calls_get();
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if (!calls)
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return -ENOSYS;
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ret = -EBADF;
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filp = fget_light(fd, &fput_needed);
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if (filp) {
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ret = calls->spu_run(filp, unpc, ustatus);
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fput_light(filp, fput_needed);
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}
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spufs_calls_put(calls);
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return ret;
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}
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int register_spu_syscalls(struct spufs_calls *calls)
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{
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if (spufs_calls)
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return -EBUSY;
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rcu_assign_pointer(spufs_calls, calls);
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return 0;
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}
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EXPORT_SYMBOL_GPL(register_spu_syscalls);
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void unregister_spu_syscalls(struct spufs_calls *calls)
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{
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BUG_ON(spufs_calls->owner != calls->owner);
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rcu_assign_pointer(spufs_calls, NULL);
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synchronize_rcu();
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}
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EXPORT_SYMBOL_GPL(unregister_spu_syscalls);
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