Messages in this thread Patch in this message | | | From | Cristian Marussi <> | Subject | [RFC PATCH 07/16] debugfs: Add signed versions of debugfs_create_u32/64 helpers | Date | Sun, 27 Feb 2022 20:55:59 +0000 |
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Add a few helpers to deal with signed values integers; built on existing debugfs internal helpers as the existing unsigned functions already do.
Make the simple_attr_write() internal helper detect the sign of the requested set operation from the related format string: this is needed to be able to properly parse negatively signed input strings.
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Signed-off-by: Cristian Marussi <cristian.marussi@arm.com> --- Note that in the rest of the series I do NOT need the s64 WRITE/SET operations, that required the more invasive simple_attr_write() change, but it seemed odd to implement a get only debug_create_s32/64 API. --- fs/debugfs/file.c | 74 +++++++++++++++++++++++++++++++++++++++++ fs/libfs.c | 12 +++++-- include/linux/debugfs.h | 4 +++ 3 files changed, 87 insertions(+), 3 deletions(-)
diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c index 950c63fa4d0b..5363b12c3dcb 100644 --- a/fs/debugfs/file.c +++ b/fs/debugfs/file.c @@ -556,6 +556,80 @@ void debugfs_create_u64(const char *name, umode_t mode, struct dentry *parent, } EXPORT_SYMBOL_GPL(debugfs_create_u64); +static int debugfs_s32_set(void *data, u64 val) +{ + *(s32 *)data = val; + return 0; +} + +static int debugfs_s32_get(void *data, u64 *val) +{ + *val = *(s32 *)data; + return 0; +} +DEFINE_DEBUGFS_ATTRIBUTE(fops_s32, debugfs_s32_get, debugfs_s32_set, "%lld\n"); +DEFINE_DEBUGFS_ATTRIBUTE(fops_s32_ro, debugfs_s32_get, NULL, "%lld\n"); +DEFINE_DEBUGFS_ATTRIBUTE(fops_s32_wo, NULL, debugfs_s32_set, "%lld\n"); + +/** + * debugfs_create_s32 - create a debugfs file that is used to read and write an signed 32-bit value + * @name: a pointer to a string containing the name of the file to create. + * @mode: the permission that the file should have + * @parent: a pointer to the parent dentry for this file. This should be a + * directory dentry if set. If this parameter is %NULL, then the + * file will be created in the root of the debugfs filesystem. + * @value: a pointer to the variable that the file should read to and write + * from. + * + * This function creates a file in debugfs with the given name that + * contains the value of the variable @value. If the @mode variable is so + * set, it can be read from, and written to. + */ +void debugfs_create_s32(const char *name, umode_t mode, struct dentry *parent, + s32 *value) +{ + debugfs_create_mode_unsafe(name, mode, parent, value, &fops_s32, + &fops_s32_ro, &fops_s32_wo); +} +EXPORT_SYMBOL_GPL(debugfs_create_s32); + +static int debugfs_s64_set(void *data, u64 val) +{ + *(s64 *)data = val; + return 0; +} + +static int debugfs_s64_get(void *data, u64 *val) +{ + *val = *(s64 *)data; + return 0; +} +DEFINE_DEBUGFS_ATTRIBUTE(fops_s64, debugfs_s64_get, debugfs_s64_set, "%lld\n"); +DEFINE_DEBUGFS_ATTRIBUTE(fops_s64_ro, debugfs_s64_get, NULL, "%lld\n"); +DEFINE_DEBUGFS_ATTRIBUTE(fops_s64_wo, NULL, debugfs_s64_set, "%lld\n"); + +/** + * debugfs_create_s64 - create a debugfs file that is used to read and write a signed 64-bit value + * @name: a pointer to a string containing the name of the file to create. + * @mode: the permission that the file should have + * @parent: a pointer to the parent dentry for this file. This should be a + * directory dentry if set. If this parameter is %NULL, then the + * file will be created in the root of the debugfs filesystem. + * @value: a pointer to the variable that the file should read to and write + * from. + * + * This function creates a file in debugfs with the given name that + * contains the value of the variable @value. If the @mode variable is so + * set, it can be read from, and written to. + */ +void debugfs_create_s64(const char *name, umode_t mode, struct dentry *parent, + s64 *value) +{ + debugfs_create_mode_unsafe(name, mode, parent, value, &fops_s64, + &fops_s64_ro, &fops_s64_wo); +} +EXPORT_SYMBOL_GPL(debugfs_create_s64); + static int debugfs_ulong_set(void *data, u64 val) { *(unsigned long *)data = val; diff --git a/fs/libfs.c b/fs/libfs.c index ba7438ab9371..f5a554ed363b 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -917,8 +917,8 @@ EXPORT_SYMBOL(simple_transaction_release); struct simple_attr { int (*get)(void *, u64 *); int (*set)(void *, u64); - char get_buf[24]; /* enough to store a u64 and "\n\0" */ - char set_buf[24]; + char get_buf[25]; /* enough to store a u64, a sign and "\n\0" */ + char set_buf[25]; void *data; const char *fmt; /* format for read operation */ struct mutex mutex; /* protects access to these buffers */ @@ -1001,6 +1001,7 @@ ssize_t simple_attr_write(struct file *file, const char __user *buf, unsigned long long val; size_t size; ssize_t ret; + char *_fmt; attr = file->private_data; if (!attr->set) @@ -1016,7 +1017,12 @@ ssize_t simple_attr_write(struct file *file, const char __user *buf, goto out; attr->set_buf[size] = '\0'; - ret = kstrtoull(attr->set_buf, 0, &val); + _fmt = strchr(attr->fmt, '%'); + /* Deduce signedness from read format string specifier */ + if (_fmt && (strchr(_fmt, 'd') || strchr(_fmt, 'i'))) + ret = kstrtoll(attr->set_buf, 0, (long long *)&val); + else + ret = kstrtoull(attr->set_buf, 0, &val); if (ret) goto out; ret = attr->set(attr->data, val); diff --git a/include/linux/debugfs.h b/include/linux/debugfs.h index c869f1e73d75..1b8ea858f261 100644 --- a/include/linux/debugfs.h +++ b/include/linux/debugfs.h @@ -114,6 +114,10 @@ void debugfs_create_u64(const char *name, umode_t mode, struct dentry *parent, u64 *value); void debugfs_create_ulong(const char *name, umode_t mode, struct dentry *parent, unsigned long *value); +void debugfs_create_s32(const char *name, umode_t mode, struct dentry *parent, + s32 *value); +void debugfs_create_s64(const char *name, umode_t mode, struct dentry *parent, + s64 *value); void debugfs_create_x8(const char *name, umode_t mode, struct dentry *parent, u8 *value); void debugfs_create_x16(const char *name, umode_t mode, struct dentry *parent, -- 2.17.1
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