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: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Peter 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.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/arch/mips/include/asm/uaccess.h b/arch/mips/include/asm/uaccess.h
index bf8b324..9722357 100644
--- a/arch/mips/include/asm/uaccess.h
+++ b/arch/mips/include/asm/uaccess.h
@@ -103,7 +103,8 @@
* @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.
*
@@ -138,7 +139,8 @@
* @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
@@ -157,7 +159,8 @@
* @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
@@ -177,7 +180,8 @@
* @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
@@ -199,7 +203,8 @@
* @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
@@ -498,7 +503,8 @@
* @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
@@ -517,7 +523,8 @@
* @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
@@ -537,7 +544,8 @@
* @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
@@ -559,7 +567,8 @@
* @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
@@ -815,7 +824,8 @@
* @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 @@
* @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 @@
* @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 @@
* @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 @@
* 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 @@
* 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.
*