[PATCH v3.1 4/7] debugfs: unproxify attribute files created through debugfs_create_*()

From: Nicolai Stange
Date: Sat Feb 13 2016 - 20:46:31 EST

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In reply to: Nicolai Stange: "[PATCH v3 7/7] debugfs: unproxify files created through debugfs_create_u32_array()"
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Currently, the struct file_operations associated with the attribute style
files created through the debugfs_create_*() helpers are not file
lifetime aware as they are defined by means of DEFINE_SIMPLE_ATTRIBUTE().

Thus, a lifetime managing proxy is created around the original fops each
time such a file is opened which is an unnecessary waste of resources.

Migrate all usages of DEFINE_SIMPLE_ATTRIBUTE() within debugfs itself
to DEFINE_DEBUGFS_ATTRIBUTE() in order to implement file lifetime managing
within the struct file_operations thus defined.

Introduce the debugfs_create_mode_unsafe() helper, analogous to
debugfs_create_mode(), but distinct in that it creates the files in
non-proxying operation mode through debugfs_create_file_unsafe().

Feed all struct file_operations migrated to DEFINE_DEBUGFS_ATTRIBUTE()
into debugfs_create_mode_unsafe() instead of former debugfs_create_mode().

Signed-off-by: Nicolai Stange <nicstange@xxxxxxxxx>
---
linux-kernel@xxxxxxxxxxxxxxx doesn't like triple-X in subject names.
and rejected that one.
s/XXX/*/. Otherwise identical to triple-X'ed original.

fs/debugfs/file.c | 123 +++++++++++++++++++++++++++++++++---------------------
1 file changed, 75 insertions(+), 48 deletions(-)

diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c
index 2da5fb0..74de110 100644
--- a/fs/debugfs/file.c
+++ b/fs/debugfs/file.c
@@ -329,6 +329,24 @@ static struct dentry *debugfs_create_mode(const char *name, umode_t mode,
return debugfs_create_file(name, mode, parent, value, fops);
}

+static struct dentry *debugfs_create_mode_unsafe(const char *name, umode_t mode,
+ struct dentry *parent, void *value,
+ const struct file_operations *fops,
+ const struct file_operations *fops_ro,
+ const struct file_operations *fops_wo)
+{
+ /* if there are no write bits set, make read only */
+ if (!(mode & S_IWUGO))
+ return debugfs_create_file_unsafe(name, mode, parent, value,
+ fops_ro);
+ /* if there are no read bits set, make write only */
+ if (!(mode & S_IRUGO))
+ return debugfs_create_file_unsafe(name, mode, parent, value,
+ fops_wo);
+
+ return debugfs_create_file_unsafe(name, mode, parent, value, fops);
+}
+
static int debugfs_u8_set(void *data, u64 val)
{
*(u8 *)data = val;
@@ -339,9 +357,9 @@ static int debugfs_u8_get(void *data, u64 *val)
*val = *(u8 *)data;
return 0;
}
-DEFINE_SIMPLE_ATTRIBUTE(fops_u8, debugfs_u8_get, debugfs_u8_set, "%llu\n");
-DEFINE_SIMPLE_ATTRIBUTE(fops_u8_ro, debugfs_u8_get, NULL, "%llu\n");
-DEFINE_SIMPLE_ATTRIBUTE(fops_u8_wo, NULL, debugfs_u8_set, "%llu\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_u8, debugfs_u8_get, debugfs_u8_set, "%llu\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_u8_ro, debugfs_u8_get, NULL, "%llu\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_u8_wo, NULL, debugfs_u8_set, "%llu\n");

/**
* debugfs_create_u8 - create a debugfs file that is used to read and write an unsigned 8-bit value
@@ -370,7 +388,7 @@ DEFINE_SIMPLE_ATTRIBUTE(fops_u8_wo, NULL, debugfs_u8_set, "%llu\n");
struct dentry *debugfs_create_u8(const char *name, umode_t mode,
struct dentry *parent, u8 *value)
{
- return debugfs_create_mode(name, mode, parent, value, &fops_u8,
+ return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u8,
&fops_u8_ro, &fops_u8_wo);
}
EXPORT_SYMBOL_GPL(debugfs_create_u8);
@@ -385,9 +403,9 @@ static int debugfs_u16_get(void *data, u64 *val)
*val = *(u16 *)data;
return 0;
}
-DEFINE_SIMPLE_ATTRIBUTE(fops_u16, debugfs_u16_get, debugfs_u16_set, "%llu\n");
-DEFINE_SIMPLE_ATTRIBUTE(fops_u16_ro, debugfs_u16_get, NULL, "%llu\n");
-DEFINE_SIMPLE_ATTRIBUTE(fops_u16_wo, NULL, debugfs_u16_set, "%llu\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_u16, debugfs_u16_get, debugfs_u16_set, "%llu\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_u16_ro, debugfs_u16_get, NULL, "%llu\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_u16_wo, NULL, debugfs_u16_set, "%llu\n");

/**
* debugfs_create_u16 - create a debugfs file that is used to read and write an unsigned 16-bit value
@@ -416,7 +434,7 @@ DEFINE_SIMPLE_ATTRIBUTE(fops_u16_wo, NULL, debugfs_u16_set, "%llu\n");
struct dentry *debugfs_create_u16(const char *name, umode_t mode,
struct dentry *parent, u16 *value)
{
- return debugfs_create_mode(name, mode, parent, value, &fops_u16,
+ return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u16,
&fops_u16_ro, &fops_u16_wo);
}
EXPORT_SYMBOL_GPL(debugfs_create_u16);
@@ -431,9 +449,9 @@ static int debugfs_u32_get(void *data, u64 *val)
*val = *(u32 *)data;
return 0;
}
-DEFINE_SIMPLE_ATTRIBUTE(fops_u32, debugfs_u32_get, debugfs_u32_set, "%llu\n");
-DEFINE_SIMPLE_ATTRIBUTE(fops_u32_ro, debugfs_u32_get, NULL, "%llu\n");
-DEFINE_SIMPLE_ATTRIBUTE(fops_u32_wo, NULL, debugfs_u32_set, "%llu\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_u32, debugfs_u32_get, debugfs_u32_set, "%llu\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_u32_ro, debugfs_u32_get, NULL, "%llu\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_u32_wo, NULL, debugfs_u32_set, "%llu\n");

/**
* debugfs_create_u32 - create a debugfs file that is used to read and write an unsigned 32-bit value
@@ -462,7 +480,7 @@ DEFINE_SIMPLE_ATTRIBUTE(fops_u32_wo, NULL, debugfs_u32_set, "%llu\n");
struct dentry *debugfs_create_u32(const char *name, umode_t mode,
struct dentry *parent, u32 *value)
{
- return debugfs_create_mode(name, mode, parent, value, &fops_u32,
+ return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u32,
&fops_u32_ro, &fops_u32_wo);
}
EXPORT_SYMBOL_GPL(debugfs_create_u32);
@@ -478,9 +496,9 @@ static int debugfs_u64_get(void *data, u64 *val)
*val = *(u64 *)data;
return 0;
}
-DEFINE_SIMPLE_ATTRIBUTE(fops_u64, debugfs_u64_get, debugfs_u64_set, "%llu\n");
-DEFINE_SIMPLE_ATTRIBUTE(fops_u64_ro, debugfs_u64_get, NULL, "%llu\n");
-DEFINE_SIMPLE_ATTRIBUTE(fops_u64_wo, NULL, debugfs_u64_set, "%llu\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_u64, debugfs_u64_get, debugfs_u64_set, "%llu\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_u64_ro, debugfs_u64_get, NULL, "%llu\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_u64_wo, NULL, debugfs_u64_set, "%llu\n");

/**
* debugfs_create_u64 - create a debugfs file that is used to read and write an unsigned 64-bit value
@@ -509,7 +527,7 @@ DEFINE_SIMPLE_ATTRIBUTE(fops_u64_wo, NULL, debugfs_u64_set, "%llu\n");
struct dentry *debugfs_create_u64(const char *name, umode_t mode,
struct dentry *parent, u64 *value)
{
- return debugfs_create_mode(name, mode, parent, value, &fops_u64,
+ return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u64,
&fops_u64_ro, &fops_u64_wo);
}
EXPORT_SYMBOL_GPL(debugfs_create_u64);
@@ -525,9 +543,10 @@ static int debugfs_ulong_get(void *data, u64 *val)
*val = *(unsigned long *)data;
return 0;
}
-DEFINE_SIMPLE_ATTRIBUTE(fops_ulong, debugfs_ulong_get, debugfs_ulong_set, "%llu\n");
-DEFINE_SIMPLE_ATTRIBUTE(fops_ulong_ro, debugfs_ulong_get, NULL, "%llu\n");
-DEFINE_SIMPLE_ATTRIBUTE(fops_ulong_wo, NULL, debugfs_ulong_set, "%llu\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong, debugfs_ulong_get, debugfs_ulong_set,
+ "%llu\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong_ro, debugfs_ulong_get, NULL, "%llu\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong_wo, NULL, debugfs_ulong_set, "%llu\n");

/**
* debugfs_create_ulong - create a debugfs file that is used to read and write
@@ -557,26 +576,30 @@ DEFINE_SIMPLE_ATTRIBUTE(fops_ulong_wo, NULL, debugfs_ulong_set, "%llu\n");
struct dentry *debugfs_create_ulong(const char *name, umode_t mode,
struct dentry *parent, unsigned long *value)
{
- return debugfs_create_mode(name, mode, parent, value, &fops_ulong,
- &fops_ulong_ro, &fops_ulong_wo);
+ return debugfs_create_mode_unsafe(name, mode, parent, value,
+ &fops_ulong, &fops_ulong_ro,
+ &fops_ulong_wo);
}
EXPORT_SYMBOL_GPL(debugfs_create_ulong);

-DEFINE_SIMPLE_ATTRIBUTE(fops_x8, debugfs_u8_get, debugfs_u8_set, "0x%02llx\n");
-DEFINE_SIMPLE_ATTRIBUTE(fops_x8_ro, debugfs_u8_get, NULL, "0x%02llx\n");
-DEFINE_SIMPLE_ATTRIBUTE(fops_x8_wo, NULL, debugfs_u8_set, "0x%02llx\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_x8, debugfs_u8_get, debugfs_u8_set, "0x%02llx\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_x8_ro, debugfs_u8_get, NULL, "0x%02llx\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_x8_wo, NULL, debugfs_u8_set, "0x%02llx\n");

-DEFINE_SIMPLE_ATTRIBUTE(fops_x16, debugfs_u16_get, debugfs_u16_set, "0x%04llx\n");
-DEFINE_SIMPLE_ATTRIBUTE(fops_x16_ro, debugfs_u16_get, NULL, "0x%04llx\n");
-DEFINE_SIMPLE_ATTRIBUTE(fops_x16_wo, NULL, debugfs_u16_set, "0x%04llx\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_x16, debugfs_u16_get, debugfs_u16_set,
+ "0x%04llx\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_x16_ro, debugfs_u16_get, NULL, "0x%04llx\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_x16_wo, NULL, debugfs_u16_set, "0x%04llx\n");

-DEFINE_SIMPLE_ATTRIBUTE(fops_x32, debugfs_u32_get, debugfs_u32_set, "0x%08llx\n");
-DEFINE_SIMPLE_ATTRIBUTE(fops_x32_ro, debugfs_u32_get, NULL, "0x%08llx\n");
-DEFINE_SIMPLE_ATTRIBUTE(fops_x32_wo, NULL, debugfs_u32_set, "0x%08llx\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_x32, debugfs_u32_get, debugfs_u32_set,
+ "0x%08llx\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_x32_ro, debugfs_u32_get, NULL, "0x%08llx\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_x32_wo, NULL, debugfs_u32_set, "0x%08llx\n");

-DEFINE_SIMPLE_ATTRIBUTE(fops_x64, debugfs_u64_get, debugfs_u64_set, "0x%016llx\n");
-DEFINE_SIMPLE_ATTRIBUTE(fops_x64_ro, debugfs_u64_get, NULL, "0x%016llx\n");
-DEFINE_SIMPLE_ATTRIBUTE(fops_x64_wo, NULL, debugfs_u64_set, "0x%016llx\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_x64, debugfs_u64_get, debugfs_u64_set,
+ "0x%016llx\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_x64_ro, debugfs_u64_get, NULL, "0x%016llx\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_x64_wo, NULL, debugfs_u64_set, "0x%016llx\n");

/*
* debugfs_create_x{8,16,32,64} - create a debugfs file that is used to read and write an unsigned {8,16,32,64}-bit value
@@ -599,7 +622,7 @@ DEFINE_SIMPLE_ATTRIBUTE(fops_x64_wo, NULL, debugfs_u64_set, "0x%016llx\n");
struct dentry *debugfs_create_x8(const char *name, umode_t mode,
struct dentry *parent, u8 *value)
{
- return debugfs_create_mode(name, mode, parent, value, &fops_x8,
+ return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x8,
&fops_x8_ro, &fops_x8_wo);
}
EXPORT_SYMBOL_GPL(debugfs_create_x8);
@@ -617,7 +640,7 @@ EXPORT_SYMBOL_GPL(debugfs_create_x8);
struct dentry *debugfs_create_x16(const char *name, umode_t mode,
struct dentry *parent, u16 *value)
{
- return debugfs_create_mode(name, mode, parent, value, &fops_x16,
+ return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x16,
&fops_x16_ro, &fops_x16_wo);
}
EXPORT_SYMBOL_GPL(debugfs_create_x16);
@@ -635,7 +658,7 @@ EXPORT_SYMBOL_GPL(debugfs_create_x16);
struct dentry *debugfs_create_x32(const char *name, umode_t mode,
struct dentry *parent, u32 *value)
{
- return debugfs_create_mode(name, mode, parent, value, &fops_x32,
+ return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x32,
&fops_x32_ro, &fops_x32_wo);
}
EXPORT_SYMBOL_GPL(debugfs_create_x32);
@@ -653,7 +676,7 @@ EXPORT_SYMBOL_GPL(debugfs_create_x32);
struct dentry *debugfs_create_x64(const char *name, umode_t mode,
struct dentry *parent, u64 *value)
{
- return debugfs_create_mode(name, mode, parent, value, &fops_x64,
+ return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x64,
&fops_x64_ro, &fops_x64_wo);
}
EXPORT_SYMBOL_GPL(debugfs_create_x64);
@@ -669,10 +692,10 @@ static int debugfs_size_t_get(void *data, u64 *val)
*val = *(size_t *)data;
return 0;
}
-DEFINE_SIMPLE_ATTRIBUTE(fops_size_t, debugfs_size_t_get, debugfs_size_t_set,
- "%llu\n"); /* %llu and %zu are more or less the same */
-DEFINE_SIMPLE_ATTRIBUTE(fops_size_t_ro, debugfs_size_t_get, NULL, "%llu\n");
-DEFINE_SIMPLE_ATTRIBUTE(fops_size_t_wo, NULL, debugfs_size_t_set, "%llu\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t, debugfs_size_t_get, debugfs_size_t_set,
+ "%llu\n"); /* %llu and %zu are more or less the same */
+DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t_ro, debugfs_size_t_get, NULL, "%llu\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t_wo, NULL, debugfs_size_t_set, "%llu\n");

/**
* debugfs_create_size_t - create a debugfs file that is used to read and write an size_t value
@@ -687,8 +710,9 @@ DEFINE_SIMPLE_ATTRIBUTE(fops_size_t_wo, NULL, debugfs_size_t_set, "%llu\n");
struct dentry *debugfs_create_size_t(const char *name, umode_t mode,
struct dentry *parent, size_t *value)
{
- return debugfs_create_mode(name, mode, parent, value, &fops_size_t,
- &fops_size_t_ro, &fops_size_t_wo);
+ return debugfs_create_mode_unsafe(name, mode, parent, value,
+ &fops_size_t, &fops_size_t_ro,
+ &fops_size_t_wo);
}
EXPORT_SYMBOL_GPL(debugfs_create_size_t);

@@ -702,10 +726,12 @@ static int debugfs_atomic_t_get(void *data, u64 *val)
*val = atomic_read((atomic_t *)data);
return 0;
}
-DEFINE_SIMPLE_ATTRIBUTE(fops_atomic_t, debugfs_atomic_t_get,
+DEFINE_DEBUGFS_ATTRIBUTE(fops_atomic_t, debugfs_atomic_t_get,
debugfs_atomic_t_set, "%lld\n");
-DEFINE_SIMPLE_ATTRIBUTE(fops_atomic_t_ro, debugfs_atomic_t_get, NULL, "%lld\n");
-DEFINE_SIMPLE_ATTRIBUTE(fops_atomic_t_wo, NULL, debugfs_atomic_t_set, "%lld\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_atomic_t_ro, debugfs_atomic_t_get, NULL,
+ "%lld\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_atomic_t_wo, NULL, debugfs_atomic_t_set,
+ "%lld\n");

/**
* debugfs_create_atomic_t - create a debugfs file that is used to read and
@@ -721,8 +747,9 @@ DEFINE_SIMPLE_ATTRIBUTE(fops_atomic_t_wo, NULL, debugfs_atomic_t_set, "%lld\n");
struct dentry *debugfs_create_atomic_t(const char *name, umode_t mode,
struct dentry *parent, atomic_t *value)
{
- return debugfs_create_mode(name, mode, parent, value, &fops_atomic_t,
- &fops_atomic_t_ro, &fops_atomic_t_wo);
+ return debugfs_create_mode_unsafe(name, mode, parent, value,
+ &fops_atomic_t, &fops_atomic_t_ro,
+ &fops_atomic_t_wo);
}
EXPORT_SYMBOL_GPL(debugfs_create_atomic_t);

--
2.7.1

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In reply to: Nicolai Stange: "[PATCH v3 7/7] debugfs: unproxify files created through debugfs_create_u32_array()"
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