[parisc-linux-cvs] linux deller
Helge Deller
deller@gmx.de
Fri, 23 Nov 2001 00:11:34 +0100
--------------Boundary-00=_AR58JOV333F6HXIZE07J
Content-Type: text/plain;
charset="iso-8859-1"
Content-Transfer-Encoding: 8bit
On Friday 23 November 2001 00:07, Helge Deller wrote:
> CVSROOT: /var/cvs
> Module name: linux
> Changes by: deller 01/11/22 16:07:57
>
> Modified files:
> . : Makefile
> include/asm-parisc: bitops.h
>
> Log message:
> - 2.4.14-pa9
> - add a few bitops inline functions to make devfs compile & working
> - added docbook comments to the bitop functions (taken from
> include/asm-i386/bitops.h)
- should be rewritten in assembler later
- this diff is nearly impossible to read since I moved a few functions around...
- tested, but it would be nice if someone looks over it again
--------------Boundary-00=_AR58JOV333F6HXIZE07J
Content-Type: text/plain;
charset="iso-8859-1";
name="diff"
Content-Transfer-Encoding: 8bit
Content-Disposition: attachment; filename="diff"
Index: Makefile
===================================================================
RCS file: /var/cvs/linux/Makefile,v
retrieving revision 1.200
diff -u -p -r1.200 Makefile
--- Makefile 2001/11/21 15:16:39 1.200
+++ Makefile 2001/11/22 23:05:14
@@ -1,7 +1,7 @@
VERSION = 2
PATCHLEVEL = 4
SUBLEVEL = 14
-EXTRAVERSION = -pa8
+EXTRAVERSION = -pa9
KERNELRELEASE=$(VERSION).$(PATCHLEVEL).$(SUBLEVEL)$(EXTRAVERSION)
Index: bitops.h
===================================================================
RCS file: /var/cvs/linux/include/asm-parisc/bitops.h,v
retrieving revision 1.14
diff -u -p -r1.14 bitops.h
--- bitops.h 2001/09/06 09:44:12 1.14
+++ bitops.h 2001/11/22 23:05:47
@@ -20,24 +20,63 @@
#define CHOP_SHIFTCOUNT(x) ((x) & (BITS_PER_LONG - 1))
-static __inline__ int test_and_set_bit(int nr, void * address)
+
+#define smp_mb__before_clear_bit() smp_mb()
+#define smp_mb__after_clear_bit() smp_mb()
+
+/**
+ * set_bit - Atomically set a bit in memory
+ * @nr: the bit to set
+ * @addr: the address to start counting from
+ *
+ * This function is atomic and may not be reordered. See __set_bit()
+ * if you do not require the atomic guarantees.
+ * Note that @nr may be almost arbitrarily large; this function is not
+ * restricted to acting on a single-word quantity.
+ */
+static __inline__ void set_bit(int nr, void * address)
{
unsigned long mask;
unsigned long *addr = (unsigned long *) address;
- int oldbit;
unsigned long flags;
addr += (nr >> SHIFT_PER_LONG);
mask = 1L << CHOP_SHIFTCOUNT(nr);
SPIN_LOCK_IRQSAVE(ATOMIC_HASH(addr), flags);
- oldbit = (*addr & mask) ? 1 : 0;
*addr |= mask;
SPIN_UNLOCK_IRQRESTORE(ATOMIC_HASH(addr), flags);
+}
- return oldbit;
+/**
+ * __set_bit - Set a bit in memory
+ * @nr: the bit to set
+ * @addr: the address to start counting from
+ *
+ * Unlike set_bit(), this function is non-atomic and may be reordered.
+ * If it's called on the same region of memory simultaneously, the effect
+ * may be that only one operation succeeds.
+ */
+static __inline__ void __set_bit(int nr, void * address)
+{
+ unsigned long mask;
+ unsigned long *addr = (unsigned long *) address;
+
+ addr += (nr >> SHIFT_PER_LONG);
+ mask = 1L << CHOP_SHIFTCOUNT(nr);
+ *addr |= mask;
}
-static __inline__ void set_bit(int nr, void * address)
+/**
+ * clear_bit - Clears a bit in memory
+ * @nr: Bit to clear
+ * @addr: Address to start counting from
+ *
+ * clear_bit() is atomic and may not be reordered. However, it does
+ * not contain a memory barrier, so if it is used for locking purposes,
+ * you should call smp_mb__before_clear_bit() and/or smp_mb__after_clear_bit()
+ * in order to ensure changes are visible on other processors.
+ */
+static __inline__ void clear_bit(int nr, void * address)
{
unsigned long mask;
unsigned long *addr = (unsigned long *) address;
@@ -46,41 +85,108 @@ static __inline__ void set_bit(int nr, v
addr += (nr >> SHIFT_PER_LONG);
mask = 1L << CHOP_SHIFTCOUNT(nr);
SPIN_LOCK_IRQSAVE(ATOMIC_HASH(addr), flags);
- *addr |= mask;
+ *addr &= ~mask;
SPIN_UNLOCK_IRQRESTORE(ATOMIC_HASH(addr), flags);
}
-static __inline__ int test_and_clear_bit(int nr, void * address)
+/**
+ * change_bit - Toggle a bit in memory
+ * @nr: Bit to clear
+ * @addr: Address to start counting from
+ *
+ * change_bit() is atomic and may not be reordered.
+ * Note that @nr may be almost arbitrarily large; this function is not
+ * restricted to acting on a single-word quantity.
+ */
+static __inline__ void change_bit(int nr, void * address)
{
unsigned long mask;
unsigned long *addr = (unsigned long *) address;
- int oldbit;
unsigned long flags;
addr += (nr >> SHIFT_PER_LONG);
mask = 1L << CHOP_SHIFTCOUNT(nr);
SPIN_LOCK_IRQSAVE(ATOMIC_HASH(addr), flags);
- oldbit = (*addr & mask) ? 1 : 0;
- *addr &= ~mask;
+ *addr ^= mask;
SPIN_UNLOCK_IRQRESTORE(ATOMIC_HASH(addr), flags);
+}
- return oldbit;
+/**
+ * __change_bit - Toggle a bit in memory
+ * @nr: the bit to set
+ * @addr: the address to start counting from
+ *
+ * Unlike change_bit(), this function is non-atomic and may be reordered.
+ * If it's called on the same region of memory simultaneously, the effect
+ * may be that only one operation succeeds.
+ */
+static __inline__ void __change_bit(int nr, void * address)
+{
+ unsigned long mask;
+ unsigned long *addr = (unsigned long *) address;
+
+ addr += (nr >> SHIFT_PER_LONG);
+ mask = 1L << CHOP_SHIFTCOUNT(nr);
+ *addr ^= mask;
}
-static __inline__ void clear_bit(int nr, void * address)
+/**
+ * test_and_set_bit - Set a bit and return its old value
+ * @nr: Bit to set
+ * @addr: Address to count from
+ *
+ * This operation is atomic and cannot be reordered.
+ * It also implies a memory barrier.
+ */
+static __inline__ int test_and_set_bit(int nr, void * address)
{
unsigned long mask;
unsigned long *addr = (unsigned long *) address;
+ int oldbit;
unsigned long flags;
addr += (nr >> SHIFT_PER_LONG);
mask = 1L << CHOP_SHIFTCOUNT(nr);
SPIN_LOCK_IRQSAVE(ATOMIC_HASH(addr), flags);
- *addr &= ~mask;
+ oldbit = (*addr & mask) ? 1 : 0;
+ *addr |= mask;
SPIN_UNLOCK_IRQRESTORE(ATOMIC_HASH(addr), flags);
+
+ return oldbit;
}
-static __inline__ int test_and_change_bit(int nr, void * address)
+/**
+ * __test_and_set_bit - Set a bit and return its old value
+ * @nr: Bit to set
+ * @addr: Address to count from
+ *
+ * This operation is non-atomic and can be reordered.
+ * If two examples of this operation race, one can appear to succeed
+ * but actually fail. You must protect multiple accesses with a lock.
+ */
+static __inline__ int __test_and_set_bit(int nr, void * address)
+{
+ unsigned long mask;
+ unsigned long *addr = (unsigned long *) address;
+ int oldbit;
+
+ addr += (nr >> SHIFT_PER_LONG);
+ mask = 1L << CHOP_SHIFTCOUNT(nr);
+ oldbit = (*addr & mask) ? 1 : 0;
+ *addr |= mask;
+
+ return oldbit;
+}
+
+/**
+ * test_and_clear_bit - Clear a bit and return its old value
+ * @nr: Bit to set
+ * @addr: Address to count from
+ *
+ * This operation is atomic and cannot be reordered.
+ * It also implies a memory barrier.
+ */
+static __inline__ int test_and_clear_bit(int nr, void * address)
{
unsigned long mask;
unsigned long *addr = (unsigned long *) address;
@@ -91,54 +197,89 @@ static __inline__ int test_and_change_bi
mask = 1L << CHOP_SHIFTCOUNT(nr);
SPIN_LOCK_IRQSAVE(ATOMIC_HASH(addr), flags);
oldbit = (*addr & mask) ? 1 : 0;
- *addr ^= mask;
+ *addr &= ~mask;
SPIN_UNLOCK_IRQRESTORE(ATOMIC_HASH(addr), flags);
return oldbit;
}
-static __inline__ int __test_and_change_bit(int nr, void * address)
+/**
+ * __test_and_clear_bit - Clear a bit and return its old value
+ * @nr: Bit to set
+ * @addr: Address to count from
+ *
+ * This operation is non-atomic and can be reordered.
+ * If two examples of this operation race, one can appear to succeed
+ * but actually fail. You must protect multiple accesses with a lock.
+ */
+static __inline__ int __test_and_clear_bit(int nr, void * address)
{
unsigned long mask;
unsigned long *addr = (unsigned long *) address;
int oldbit;
addr += (nr >> SHIFT_PER_LONG);
-
mask = 1L << CHOP_SHIFTCOUNT(nr);
oldbit = (*addr & mask) ? 1 : 0;
- *addr ^= mask;
+ *addr &= ~mask;
return oldbit;
}
-static __inline__ void change_bit(int nr, void * address)
+/**
+ * test_and_change_bit - Change a bit and return its new value
+ * @nr: Bit to set
+ * @addr: Address to count from
+ *
+ * This operation is atomic and cannot be reordered.
+ * It also implies a memory barrier.
+ */
+static __inline__ int test_and_change_bit(int nr, void * address)
{
unsigned long mask;
unsigned long *addr = (unsigned long *) address;
+ int oldbit;
unsigned long flags;
addr += (nr >> SHIFT_PER_LONG);
mask = 1L << CHOP_SHIFTCOUNT(nr);
SPIN_LOCK_IRQSAVE(ATOMIC_HASH(addr), flags);
+ oldbit = (*addr & mask) ? 1 : 0;
*addr ^= mask;
SPIN_UNLOCK_IRQRESTORE(ATOMIC_HASH(addr), flags);
+
+ return oldbit;
}
-/* see asm-i386/bitops.h */
-static __inline__ void __change_bit(int nr, void * address)
+/**
+ * __test_and_change_bit - Change a bit and return its new value
+ * @nr: Bit to set
+ * @addr: Address to count from
+ *
+ * This operation is non-atomic and can be reordered.
+ * If two examples of this operation race, one can appear to succeed
+ * but actually fail. You must protect multiple accesses with a lock.
+ */
+static __inline__ int __test_and_change_bit(int nr, void * address)
{
unsigned long mask;
unsigned long *addr = (unsigned long *) address;
+ int oldbit;
addr += (nr >> SHIFT_PER_LONG);
mask = 1L << CHOP_SHIFTCOUNT(nr);
+ oldbit = (*addr & mask) ? 1 : 0;
*addr ^= mask;
-}
-/* again, the read-only case doesn't have to do any locking */
+ return oldbit;
+}
-static __inline__ int test_bit(int nr, const volatile void *address)
+/**
+ * test_bit - Determine whether a bit is set
+ * @nr: bit number to test
+ * @addr: Address to start counting from
+ */
+static __inline__ int test_bit(int nr, const void *address)
{
unsigned long mask;
unsigned long *addr = (unsigned long *) address;
@@ -149,17 +290,18 @@ static __inline__ int test_bit(int nr, c
return !!(*addr & mask);
}
-#define smp_mb__before_clear_bit() smp_mb()
-#define smp_mb__after_clear_bit() smp_mb()
-
-/* XXX We'd need some binary search here */
-
+/**
+ * ffz - find first zero in word.
+ * @word: The word to search
+ *
+ * Undefined if no zero exists, so code should check against ~0UL first.
+ */
extern __inline__ unsigned long ffz(unsigned long word)
{
unsigned long result;
result = 0;
- while(word & 1) {
+ while (word & 1) {
result++;
word >>= 1;
}
@@ -195,6 +337,12 @@ extern __inline__ unsigned long ffz(unsi
#define find_first_zero_bit(addr, size) \
find_next_zero_bit((addr), (size), 0)
+/**
+ * find_next_zero_bit - find the first zero bit in a memory region
+ * @addr: The address to base the search on
+ * @offset: The bitnumber to start searching at
+ * @size: The maximum size to search
+ */
static __inline__ unsigned long find_next_zero_bit(void * addr, unsigned long size, unsigned long offset)
{
unsigned long * p = ((unsigned long *) addr) + (offset >> SHIFT_PER_LONG);
--------------Boundary-00=_AR58JOV333F6HXIZE07J--