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Many struct file_operations in the kernel can be "const". Marking them const moves these to the .rodata section, which avoids false sharing with potential dirty data. In addition it'll catch accidental writes at compile time to these shared resources. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
136 lines
3.2 KiB
C
136 lines
3.2 KiB
C
/**
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* @file oprofile_files.c
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*
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* @remark Copyright 2002 OProfile authors
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* @remark Read the file COPYING
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*
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* @author John Levon <levon@movementarian.org>
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*/
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#include <linux/fs.h>
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#include <linux/oprofile.h>
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#include "event_buffer.h"
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#include "oprofile_stats.h"
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#include "oprof.h"
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unsigned long fs_buffer_size = 131072;
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unsigned long fs_cpu_buffer_size = 8192;
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unsigned long fs_buffer_watershed = 32768; /* FIXME: tune */
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static ssize_t depth_read(struct file * file, char __user * buf, size_t count, loff_t * offset)
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{
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return oprofilefs_ulong_to_user(backtrace_depth, buf, count, offset);
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}
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static ssize_t depth_write(struct file * file, char const __user * buf, size_t count, loff_t * offset)
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{
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unsigned long val;
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int retval;
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if (*offset)
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return -EINVAL;
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retval = oprofilefs_ulong_from_user(&val, buf, count);
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if (retval)
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return retval;
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retval = oprofile_set_backtrace(val);
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if (retval)
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return retval;
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return count;
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}
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static const struct file_operations depth_fops = {
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.read = depth_read,
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.write = depth_write
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};
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static ssize_t pointer_size_read(struct file * file, char __user * buf, size_t count, loff_t * offset)
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{
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return oprofilefs_ulong_to_user(sizeof(void *), buf, count, offset);
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}
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static const struct file_operations pointer_size_fops = {
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.read = pointer_size_read,
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};
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static ssize_t cpu_type_read(struct file * file, char __user * buf, size_t count, loff_t * offset)
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{
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return oprofilefs_str_to_user(oprofile_ops.cpu_type, buf, count, offset);
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}
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static const struct file_operations cpu_type_fops = {
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.read = cpu_type_read,
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};
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static ssize_t enable_read(struct file * file, char __user * buf, size_t count, loff_t * offset)
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{
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return oprofilefs_ulong_to_user(oprofile_started, buf, count, offset);
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}
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static ssize_t enable_write(struct file * file, char const __user * buf, size_t count, loff_t * offset)
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{
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unsigned long val;
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int retval;
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if (*offset)
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return -EINVAL;
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retval = oprofilefs_ulong_from_user(&val, buf, count);
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if (retval)
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return retval;
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if (val)
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retval = oprofile_start();
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else
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oprofile_stop();
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if (retval)
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return retval;
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return count;
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}
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static const struct file_operations enable_fops = {
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.read = enable_read,
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.write = enable_write,
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};
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static ssize_t dump_write(struct file * file, char const __user * buf, size_t count, loff_t * offset)
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{
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wake_up_buffer_waiter();
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return count;
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}
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static const struct file_operations dump_fops = {
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.write = dump_write,
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};
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void oprofile_create_files(struct super_block * sb, struct dentry * root)
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{
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oprofilefs_create_file(sb, root, "enable", &enable_fops);
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oprofilefs_create_file_perm(sb, root, "dump", &dump_fops, 0666);
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oprofilefs_create_file(sb, root, "buffer", &event_buffer_fops);
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oprofilefs_create_ulong(sb, root, "buffer_size", &fs_buffer_size);
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oprofilefs_create_ulong(sb, root, "buffer_watershed", &fs_buffer_watershed);
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oprofilefs_create_ulong(sb, root, "cpu_buffer_size", &fs_cpu_buffer_size);
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oprofilefs_create_file(sb, root, "cpu_type", &cpu_type_fops);
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oprofilefs_create_file(sb, root, "backtrace_depth", &depth_fops);
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oprofilefs_create_file(sb, root, "pointer_size", &pointer_size_fops);
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oprofile_create_stats_files(sb, root);
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if (oprofile_ops.create_files)
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oprofile_ops.create_files(sb, root);
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}
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