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	 9d5b7c956b
			
		
	
	
		9d5b7c956b
		
	
	
	
	
		
			
			Using the ksys_fadvise64_64() helper allows us to avoid the in-kernel calls to the sys_fadvise64_64() syscall. The ksys_ prefix denotes that this function is meant as a drop-in replacement for the syscall. In particular, it uses the same calling convention as ksys_fadvise64_64(). Some compat stubs called sys_fadvise64(), which then just passed through the arguments to sys_fadvise64_64(). Get rid of this indirection, and call ksys_fadvise64_64() directly. This patch is part of a series which removes in-kernel calls to syscalls. On this basis, the syscall entry path can be streamlined. For details, see http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net Cc: Andrew Morton <akpm@linux-foundation.org> Cc: linux-mm@kvack.org Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
		
			
				
	
	
		
			61 lines
		
	
	
	
		
			1.5 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			61 lines
		
	
	
	
		
			1.5 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| // SPDX-License-Identifier: GPL-2.0
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| #include <linux/errno.h>
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| #include <linux/sched.h>
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| #include <linux/sched/task_stack.h>
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| #include <linux/mm.h>
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| #include <linux/smp.h>
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| #include <linux/sem.h>
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| #include <linux/msg.h>
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| #include <linux/shm.h>
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| #include <linux/stat.h>
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| #include <linux/syscalls.h>
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| #include <linux/mman.h>
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| #include <linux/file.h>
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| #include <linux/module.h>
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| #include <linux/fs.h>
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| #include <linux/ipc.h>
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| #include <asm/cacheflush.h>
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| #include <linux/uaccess.h>
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| #include <asm/unistd.h>
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| #include <asm/syscalls.h>
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| 
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| /*
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|  * sys_pipe() is the normal C calling standard for creating
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|  * a pipe. It's not the way Unix traditionally does this, though.
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|  */
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| asmlinkage int sys_sh_pipe(void)
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| {
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| 	int fd[2];
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| 	int error;
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| 
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| 	error = do_pipe_flags(fd, 0);
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| 	if (!error) {
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| 		current_pt_regs()->regs[1] = fd[1];
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| 		return fd[0];
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| 	}
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| 	return error;
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| }
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| 
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| asmlinkage ssize_t sys_pread_wrapper(unsigned int fd, char __user *buf,
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| 			     size_t count, long dummy, loff_t pos)
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| {
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| 	return ksys_pread64(fd, buf, count, pos);
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| }
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| 
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| asmlinkage ssize_t sys_pwrite_wrapper(unsigned int fd, const char __user *buf,
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| 			      size_t count, long dummy, loff_t pos)
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| {
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| 	return ksys_pwrite64(fd, buf, count, pos);
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| }
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| 
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| asmlinkage int sys_fadvise64_64_wrapper(int fd, u32 offset0, u32 offset1,
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| 				u32 len0, u32 len1, int advice)
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| {
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| #ifdef  __LITTLE_ENDIAN__
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| 	return ksys_fadvise64_64(fd, (u64)offset1 << 32 | offset0,
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| 				 (u64)len1 << 32 | len0, advice);
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| #else
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| 	return ksys_fadvise64_64(fd, (u64)offset0 << 32 | offset1,
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| 				 (u64)len0 << 32 | len1, advice);
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| #endif
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| }
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