Commit b3c395ef authored by David Hildenbrand's avatar David Hildenbrand Committed by Ingo Molnar

mm/uaccess, mm/fault: Clarify that uaccess may only sleep if pagefaults are enabled

In general, non-atomic variants of user access functions must not sleep
if pagefaults are disabled.

Let's update all relevant comments in uaccess code. This also reflects
the might_sleep() checks in might_fault().
Reviewed-and-tested-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: David.Laight@ACULAB.COM
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: airlied@linux.ie
Cc: akpm@linux-foundation.org
Cc: benh@kernel.crashing.org
Cc: bigeasy@linutronix.de
Cc: borntraeger@de.ibm.com
Cc: daniel.vetter@intel.com
Cc: heiko.carstens@de.ibm.com
Cc: herbert@gondor.apana.org.au
Cc: hocko@suse.cz
Cc: hughd@google.com
Cc: mst@redhat.com
Cc: paulus@samba.org
Cc: ralf@linux-mips.org
Cc: schwidefsky@de.ibm.com
Cc: yang.shi@windriver.com
Link: http://lkml.kernel.org/r/1431359540-32227-4-git-send-email-dahi@linux.vnet.ibm.comSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 9ec23531
......@@ -97,7 +97,8 @@ static inline __kernel_size_t __copy_from_user(void *to,
* @x: Value to copy to user space.
* @ptr: Destination address, in user space.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* This macro copies a single simple value from kernel space to user
* space. It supports simple types like char and int, but not larger
......@@ -116,7 +117,8 @@ static inline __kernel_size_t __copy_from_user(void *to,
* @x: Variable to store result.
* @ptr: Source address, in user space.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* This macro copies a single simple variable from user space to kernel
* space. It supports simple types like char and int, but not larger
......@@ -136,7 +138,8 @@ static inline __kernel_size_t __copy_from_user(void *to,
* @x: Value to copy to user space.
* @ptr: Destination address, in user space.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* This macro copies a single simple value from kernel space to user
* space. It supports simple types like char and int, but not larger
......@@ -158,7 +161,8 @@ static inline __kernel_size_t __copy_from_user(void *to,
* @x: Variable to store result.
* @ptr: Source address, in user space.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* This macro copies a single simple variable from user space to kernel
* space. It supports simple types like char and int, but not larger
......
......@@ -36,7 +36,8 @@
* @addr: User space pointer to start of block to check
* @size: Size of block to check
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* Checks if a pointer to a block of memory in user space is valid.
*
......
......@@ -91,7 +91,8 @@ static inline void set_fs(mm_segment_t s)
* @addr: User space pointer to start of block to check
* @size: Size of block to check
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* Checks if a pointer to a block of memory in user space is valid.
*
......@@ -155,7 +156,8 @@ extern int fixup_exception(struct pt_regs *regs);
* @x: Variable to store result.
* @ptr: Source address, in user space.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* This macro copies a single simple variable from user space to kernel
* space. It supports simple types like char and int, but not larger
......@@ -175,7 +177,8 @@ extern int fixup_exception(struct pt_regs *regs);
* @x: Value to copy to user space.
* @ptr: Destination address, in user space.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* This macro copies a single simple value from kernel space to user
* space. It supports simple types like char and int, but not larger
......@@ -194,7 +197,8 @@ extern int fixup_exception(struct pt_regs *regs);
* @x: Variable to store result.
* @ptr: Source address, in user space.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* This macro copies a single simple variable from user space to kernel
* space. It supports simple types like char and int, but not larger
......@@ -274,7 +278,8 @@ do { \
* @x: Value to copy to user space.
* @ptr: Destination address, in user space.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* This macro copies a single simple value from kernel space to user
* space. It supports simple types like char and int, but not larger
......@@ -568,7 +573,8 @@ unsigned long __generic_copy_from_user(void *, const void __user *, unsigned lon
* @from: Source address, in kernel space.
* @n: Number of bytes to copy.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* Copy data from kernel space to user space. Caller must check
* the specified block with access_ok() before calling this function.
......@@ -588,7 +594,8 @@ unsigned long __generic_copy_from_user(void *, const void __user *, unsigned lon
* @from: Source address, in kernel space.
* @n: Number of bytes to copy.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* Copy data from kernel space to user space.
*
......@@ -606,7 +613,8 @@ unsigned long __generic_copy_from_user(void *, const void __user *, unsigned lon
* @from: Source address, in user space.
* @n: Number of bytes to copy.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* Copy data from user space to kernel space. Caller must check
* the specified block with access_ok() before calling this function.
......@@ -626,7 +634,8 @@ unsigned long __generic_copy_from_user(void *, const void __user *, unsigned lon
* @from: Source address, in user space.
* @n: Number of bytes to copy.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* Copy data from user space to kernel space.
*
......@@ -677,7 +686,8 @@ unsigned long clear_user(void __user *mem, unsigned long len);
* strlen_user: - Get the size of a string in user space.
* @str: The string to measure.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* Get the size of a NUL-terminated string in user space.
*
......
......@@ -178,7 +178,8 @@ extern long __user_bad(void);
* @x: Variable to store result.
* @ptr: Source address, in user space.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* This macro copies a single simple variable from user space to kernel
* space. It supports simple types like char and int, but not larger
......@@ -290,7 +291,8 @@ extern long __user_bad(void);
* @x: Value to copy to user space.
* @ptr: Destination address, in user space.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* This macro copies a single simple value from kernel space to user
* space. It supports simple types like char and int, but not larger
......
......@@ -103,7 +103,8 @@ extern u64 __ua_limit;
* @addr: User space pointer to start of block to check
* @size: Size of block to check
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* Checks if a pointer to a block of memory in user space is valid.
*
......@@ -138,7 +139,8 @@ extern u64 __ua_limit;
* @x: Value to copy to user space.
* @ptr: Destination address, in user space.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* This macro copies a single simple value from kernel space to user
* space. It supports simple types like char and int, but not larger
......@@ -157,7 +159,8 @@ extern u64 __ua_limit;
* @x: Variable to store result.
* @ptr: Source address, in user space.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* This macro copies a single simple variable from user space to kernel
* space. It supports simple types like char and int, but not larger
......@@ -177,7 +180,8 @@ extern u64 __ua_limit;
* @x: Value to copy to user space.
* @ptr: Destination address, in user space.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* This macro copies a single simple value from kernel space to user
* space. It supports simple types like char and int, but not larger
......@@ -199,7 +203,8 @@ extern u64 __ua_limit;
* @x: Variable to store result.
* @ptr: Source address, in user space.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* This macro copies a single simple variable from user space to kernel
* space. It supports simple types like char and int, but not larger
......@@ -498,7 +503,8 @@ extern void __put_user_unknown(void);
* @x: Value to copy to user space.
* @ptr: Destination address, in user space.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* This macro copies a single simple value from kernel space to user
* space. It supports simple types like char and int, but not larger
......@@ -517,7 +523,8 @@ extern void __put_user_unknown(void);
* @x: Variable to store result.
* @ptr: Source address, in user space.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* This macro copies a single simple variable from user space to kernel
* space. It supports simple types like char and int, but not larger
......@@ -537,7 +544,8 @@ extern void __put_user_unknown(void);
* @x: Value to copy to user space.
* @ptr: Destination address, in user space.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* This macro copies a single simple value from kernel space to user
* space. It supports simple types like char and int, but not larger
......@@ -559,7 +567,8 @@ extern void __put_user_unknown(void);
* @x: Variable to store result.
* @ptr: Source address, in user space.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* This macro copies a single simple variable from user space to kernel
* space. It supports simple types like char and int, but not larger
......@@ -815,7 +824,8 @@ extern size_t __copy_user(void *__to, const void *__from, size_t __n);
* @from: Source address, in kernel space.
* @n: Number of bytes to copy.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* Copy data from kernel space to user space. Caller must check
* the specified block with access_ok() before calling this function.
......@@ -888,7 +898,8 @@ extern size_t __copy_user_inatomic(void *__to, const void *__from, size_t __n);
* @from: Source address, in kernel space.
* @n: Number of bytes to copy.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* Copy data from kernel space to user space.
*
......@@ -1075,7 +1086,8 @@ extern size_t __copy_in_user_eva(void *__to, const void *__from, size_t __n);
* @from: Source address, in user space.
* @n: Number of bytes to copy.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* Copy data from user space to kernel space. Caller must check
* the specified block with access_ok() before calling this function.
......@@ -1107,7 +1119,8 @@ extern size_t __copy_in_user_eva(void *__to, const void *__from, size_t __n);
* @from: Source address, in user space.
* @n: Number of bytes to copy.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* Copy data from user space to kernel space.
*
......@@ -1329,7 +1342,8 @@ strncpy_from_user(char *__to, const char __user *__from, long __len)
* strlen_user: - Get the size of a string in user space.
* @str: The string to measure.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* Get the size of a NUL-terminated string in user space.
*
......@@ -1398,7 +1412,8 @@ static inline long __strnlen_user(const char __user *s, long n)
* strnlen_user: - Get the size of a string in user space.
* @str: The string to measure.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* Get the size of a NUL-terminated string in user space.
*
......
......@@ -98,7 +98,8 @@ static inline unsigned long extable_fixup(const struct exception_table_entry *x)
* @from: Source address, in user space.
* @n: Number of bytes to copy.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* Copy data from user space to kernel space. Caller must check
* the specified block with access_ok() before calling this function.
......@@ -118,7 +119,8 @@ unsigned long __must_check __copy_from_user(void *to, const void __user *from,
* @from: Source address, in kernel space.
* @n: Number of bytes to copy.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* Copy data from kernel space to user space. Caller must check
* the specified block with access_ok() before calling this function.
......@@ -264,7 +266,8 @@ int __get_user_bad(void) __attribute__((noreturn));
* @from: Source address, in kernel space.
* @n: Number of bytes to copy.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* Copy data from kernel space to user space.
*
......@@ -290,7 +293,8 @@ __compiletime_warning("copy_from_user() buffer size is not provably correct")
* @from: Source address, in user space.
* @n: Number of bytes to copy.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* Copy data from user space to kernel space.
*
......@@ -348,7 +352,8 @@ static inline unsigned long strnlen_user(const char __user *src, unsigned long n
* strlen_user: - Get the size of a string in user space.
* @str: The string to measure.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* Get the size of a NUL-terminated string in user space.
*
......
......@@ -36,7 +36,8 @@
* @addr: User space pointer to start of block to check
* @size: Size of block to check
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* Checks if a pointer to a block of memory in user space is valid.
*
......@@ -61,7 +62,8 @@
* @x: Value to copy to user space.
* @ptr: Destination address, in user space.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* This macro copies a single simple value from kernel space to user
* space. It supports simple types like char and int, but not larger
......@@ -79,7 +81,8 @@
* @x: Variable to store result.
* @ptr: Source address, in user space.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* This macro copies a single simple variable from user space to kernel
* space. It supports simple types like char and int, but not larger
......@@ -98,7 +101,8 @@
* @x: Value to copy to user space.
* @ptr: Destination address, in user space.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* This macro copies a single simple value from kernel space to user
* space. It supports simple types like char and int, but not larger
......@@ -119,7 +123,8 @@
* @x: Variable to store result.
* @ptr: Source address, in user space.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* This macro copies a single simple variable from user space to kernel
* space. It supports simple types like char and int, but not larger
......
......@@ -78,7 +78,8 @@ int __range_ok(unsigned long addr, unsigned long size);
* @addr: User space pointer to start of block to check
* @size: Size of block to check
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* Checks if a pointer to a block of memory in user space is valid.
*
......@@ -192,7 +193,8 @@ extern int __get_user_bad(void)
* @x: Variable to store result.
* @ptr: Source address, in user space.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* This macro copies a single simple variable from user space to kernel
* space. It supports simple types like char and int, but not larger
......@@ -274,7 +276,8 @@ extern int __put_user_bad(void)
* @x: Value to copy to user space.
* @ptr: Destination address, in user space.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* This macro copies a single simple value from kernel space to user
* space. It supports simple types like char and int, but not larger
......@@ -330,7 +333,8 @@ extern int __put_user_bad(void)
* @from: Source address, in kernel space.
* @n: Number of bytes to copy.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* Copy data from kernel space to user space. Caller must check
* the specified block with access_ok() before calling this function.
......@@ -366,7 +370,8 @@ copy_to_user(void __user *to, const void *from, unsigned long n)
* @from: Source address, in user space.
* @n: Number of bytes to copy.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* Copy data from user space to kernel space. Caller must check
* the specified block with access_ok() before calling this function.
......@@ -437,7 +442,8 @@ static inline unsigned long __must_check copy_from_user(void *to,
* @from: Source address, in user space.
* @n: Number of bytes to copy.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* Copy data from user space to user space. Caller must check
* the specified blocks with access_ok() before calling this function.
......
......@@ -74,7 +74,8 @@ static inline bool __chk_range_not_ok(unsigned long addr, unsigned long size, un
* @addr: User space pointer to start of block to check
* @size: Size of block to check
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* Checks if a pointer to a block of memory in user space is valid.
*
......@@ -145,7 +146,8 @@ __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL))
* @x: Variable to store result.
* @ptr: Source address, in user space.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* This macro copies a single simple variable from user space to kernel
* space. It supports simple types like char and int, but not larger
......@@ -240,7 +242,8 @@ extern void __put_user_8(void);
* @x: Value to copy to user space.
* @ptr: Destination address, in user space.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* This macro copies a single simple value from kernel space to user
* space. It supports simple types like char and int, but not larger
......@@ -455,7 +458,8 @@ struct __large_struct { unsigned long buf[100]; };
* @x: Variable to store result.
* @ptr: Source address, in user space.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* This macro copies a single simple variable from user space to kernel
* space. It supports simple types like char and int, but not larger
......@@ -479,7 +483,8 @@ struct __large_struct { unsigned long buf[100]; };
* @x: Value to copy to user space.
* @ptr: Destination address, in user space.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* This macro copies a single simple value from kernel space to user
* space. It supports simple types like char and int, but not larger
......
......@@ -70,7 +70,8 @@ __copy_to_user_inatomic(void __user *to, const void *from, unsigned long n)
* @from: Source address, in kernel space.
* @n: Number of bytes to copy.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* Copy data from kernel space to user space. Caller must check
* the specified block with access_ok() before calling this function.
......@@ -117,7 +118,8 @@ __copy_from_user_inatomic(void *to, const void __user *from, unsigned long n)
* @from: Source address, in user space.
* @n: Number of bytes to copy.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* Copy data from user space to kernel space. Caller must check
* the specified block with access_ok() before calling this function.
......
......@@ -647,7 +647,8 @@ EXPORT_SYMBOL(__copy_from_user_ll_nocache_nozero);
* @from: Source address, in kernel space.
* @n: Number of bytes to copy.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* Copy data from kernel space to user space.
*
......@@ -668,7 +669,8 @@ EXPORT_SYMBOL(_copy_to_user);
* @from: Source address, in user space.
* @n: Number of bytes to copy.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* Copy data from user space to kernel space.
*
......
......@@ -84,7 +84,8 @@ static inline long do_strnlen_user(const char __user *src, unsigned long count,
* @str: The string to measure.
* @count: Maximum count (including NUL character)
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* Get the size of a NUL-terminated string in user space.
*
......@@ -113,7 +114,8 @@ EXPORT_SYMBOL(strnlen_user);
* strlen_user: - Get the size of a user string INCLUDING final NUL.
* @str: The string to measure.
*
* Context: User context only. This function may sleep.
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* Get the size of a NUL-terminated string in user space.
*
......
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