[PATCH 1/7] bitmap: Introduce bitmap_set, bitmap_clear, bitmap_find_next_zero_area

[PATCH 1/7] bitmap: Introduce bitmap_set, bitmap_clear, bitmap_find_next_zero_area

[Akinobu Mita]

This introduces new bitmap functions:

bitmap_set: Set specified bit area
bitmap_clear: Clear specified bit area
bitmap_find_next_zero_area: Find free bit area

These are mostly stolen from iommu helper. The differences are:

- Use find_next_bit instead of doing test_bit for each bit

- Rewrite bitmap_set and bitmap_clear

  Instead of setting or clearing for each bit.

- Check the last bit of the limit

  iommu-helper doesn't want to find such area

- The return value if there is no zero area

  find_next_zero_area in iommu helper: returns -1
  bitmap_find_next_zero_area: return >= bitmap size

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: sparclinux@vger.kernel.org
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: linuxppc-dev@ozlabs.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Lothar Wassmann <LW@KARO-electronics.de>
Cc: linux-usb@vger.kernel.org
Cc: Roland Dreier <rolandd@cisco.com>
Cc: Yevgeny Petrilin <yevgenyp@mellanox.co.il>
Cc: netdev@vger.kernel.org
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: linux-ia64@vger.kernel.org
Cc: linux-altix@sgi.com
Cc: Joerg Roedel <joerg.roedel@amd.com>
---
 include/linux/bitmap.h |   11 ++++++
 lib/bitmap.c           |   81 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 92 insertions(+), 0 deletions(-)

diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h
index 756d78b..daf8c48 100644
--- a/include/linux/bitmap.h
+++ b/include/linux/bitmap.h
@@ -42,6 +42,9 @@
  * bitmap_empty(src, nbits)			Are all bits zero in *src?
  * bitmap_full(src, nbits)			Are all bits set in *src?
  * bitmap_weight(src, nbits)			Hamming Weight: number set bits
+ * bitmap_set(dst, pos, nbits)			Set specified bit area
+ * bitmap_clear(dst, pos, nbits)		Clear specified bit area
+ * bitmap_find_next_zero_area(buf, len, pos, n, mask)	Find bit free area
  * bitmap_shift_right(dst, src, n, nbits)	*dst = *src >> n
  * bitmap_shift_left(dst, src, n, nbits)	*dst = *src << n
  * bitmap_remap(dst, src, old, new, nbits)	*dst = map(old, new)(src)
@@ -108,6 +111,14 @@ extern int __bitmap_subset(const unsigned long *bitmap1,
 			const unsigned long *bitmap2, int bits);
 extern int __bitmap_weight(const unsigned long *bitmap, int bits);
 
+extern void bitmap_set(unsigned long *map, int i, int len);
+extern void bitmap_clear(unsigned long *map, int start, int nr);
+extern unsigned long bitmap_find_next_zero_area(unsigned long *map,
+					 unsigned long size,
+					 unsigned long start,
+					 unsigned int nr,
+					 unsigned long align_mask);
+
 extern int bitmap_scnprintf(char *buf, unsigned int len,
 			const unsigned long *src, int nbits);
 extern int __bitmap_parse(const char *buf, unsigned int buflen, int is_user,
diff --git a/lib/bitmap.c b/lib/bitmap.c
index 7025658..11bf497 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -271,6 +271,87 @@ int __bitmap_weight(const unsigned long *bitmap, int bits)
 }
 EXPORT_SYMBOL(__bitmap_weight);
 
+#define BITMAP_FIRST_WORD_MASK(start) (~0UL << ((start) % BITS_PER_LONG))
+
+void bitmap_set(unsigned long *map, int start, int nr)
+{
+	unsigned long *p = map + BIT_WORD(start);
+	const int size = start + nr;
+	int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
+	unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
+
+	while (nr - bits_to_set >= 0) {
+		*p |= mask_to_set;
+		nr -= bits_to_set;
+		bits_to_set = BITS_PER_LONG;
+		mask_to_set = ~0UL;
+		p++;
+	}
+	if (nr) {
+		mask_to_set &= BITMAP_LAST_WORD_MASK(size);
+		*p |= mask_to_set;
+	}
+}
+EXPORT_SYMBOL(bitmap_set);
+
+void bitmap_clear(unsigned long *map, int start, int nr)
+{
+	unsigned long *p = map + BIT_WORD(start);
+	const int size = start + nr;
+	int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
+	unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
+
+	while (nr - bits_to_clear >= 0) {
+		*p &= ~mask_to_clear;
+		nr -= bits_to_clear;
+		bits_to_clear = BITS_PER_LONG;
+		mask_to_clear = ~0UL;
+		p++;
+	}
+	if (nr) {
+		mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
+		*p &= ~mask_to_clear;
+	}
+}
+EXPORT_SYMBOL(bitmap_clear);
+
+/*
+ * bitmap_find_next_zero_area - find a contiguous aligned zero area
+ * @map: The address to base the search on
+ * @size: The bitmap size in bits
+ * @start: The bitnumber to start searching at
+ * @nr: The number of zeroed bits we're looking for
+ * @align_mask: Alignment mask for zero area
+ *
+ * The @align_mask should be one less than a power of 2; the effect is that
+ * the bit offset of all zero areas this function finds is multiples of that
+ * power of 2. A @align_mask of 0 means no alignment is required.
+ */
+unsigned long bitmap_find_next_zero_area(unsigned long *map,
+					 unsigned long size,
+					 unsigned long start,
+					 unsigned int nr,
+					 unsigned long align_mask)
+{
+	unsigned long index, end, i;
+again:
+	index = find_next_zero_bit(map, size, start);
+
+	/* Align allocation */
+	index = __ALIGN_MASK(index, align_mask);
+
+	end = index + nr;
+	if (end > size)
+		return end;
+	i = find_next_bit(map, end, index);
+	if (i < end) {
+		start = i + 1;
+		goto again;
+	}
+	return index;
+}
+EXPORT_SYMBOL(bitmap_find_next_zero_area);
+
 /*
  * Bitmap printing & parsing functions: first version by Bill Irwin,
  * second version by Paul Jackson, third by Joe Korty.
-- 
1.6.5.1

[PATCH 2/7] iommu-helper: Use bitmap library

[Akinobu Mita]

Use bitmap library and kill some unused iommu helper functions.

1. s/iommu_area_free/bitmap_clear/

2. s/iommu_area_reserve/bitmap_set/

3. Use bitmap_find_next_zero_area instead of find_next_zero_area

  This cannot be simple substitution because find_next_zero_area
  doesn't check the last bit of the limit in bitmap

4. Remove iommu_area_free, iommu_area_reserve, and find_next_zero_area

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: sparclinux@vger.kernel.org
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: linuxppc-dev@ozlabs.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Joerg Roedel <joerg.roedel@amd.com>
---
 arch/powerpc/kernel/iommu.c      |    4 +-
 arch/sparc/kernel/iommu.c        |    3 +-
 arch/x86/kernel/amd_iommu.c      |    4 +-
 arch/x86/kernel/pci-calgary_64.c |    6 ++--
 arch/x86/kernel/pci-gart_64.c    |    6 ++--
 include/linux/iommu-helper.h     |    3 --
 lib/iommu-helper.c               |   59 ++++++--------------------------------
 7 files changed, 21 insertions(+), 64 deletions(-)

diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index fd51578..5547ae6 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -30,7 +30,7 @@
 #include <linux/spinlock.h>
 #include <linux/string.h>
 #include <linux/dma-mapping.h>
-#include <linux/bitops.h>
+#include <linux/bitmap.h>
 #include <linux/iommu-helper.h>
 #include <linux/crash_dump.h>
 #include <asm/io.h>
@@ -251,7 +251,7 @@ static void __iommu_free(struct iommu_table *tbl, dma_addr_t dma_addr,
 	}
 
 	ppc_md.tce_free(tbl, entry, npages);
-	iommu_area_free(tbl->it_map, free_entry, npages);
+	bitmap_clear(tbl->it_map, free_entry, npages);
 }
 
 static void iommu_free(struct iommu_table *tbl, dma_addr_t dma_addr,
diff --git a/arch/sparc/kernel/iommu.c b/arch/sparc/kernel/iommu.c
index 7690cc2..5fad949 100644
--- a/arch/sparc/kernel/iommu.c
+++ b/arch/sparc/kernel/iommu.c
@@ -11,6 +11,7 @@
 #include <linux/dma-mapping.h>
 #include <linux/errno.h>
 #include <linux/iommu-helper.h>
+#include <linux/bitmap.h>
 
 #ifdef CONFIG_PCI
 #include <linux/pci.h>
@@ -169,7 +170,7 @@ void iommu_range_free(struct iommu *iommu, dma_addr_t dma_addr, unsigned long np
 
 	entry = (dma_addr - iommu->page_table_map_base) >> IO_PAGE_SHIFT;
 
-	iommu_area_free(arena->map, entry, npages);
+	bitmap_clear(arena->map, entry, npages);
 }
 
 int iommu_table_init(struct iommu *iommu, int tsbsize,
diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index 98f230f..08b1d20 100644
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -19,7 +19,7 @@
 
 #include <linux/pci.h>
 #include <linux/gfp.h>
-#include <linux/bitops.h>
+#include <linux/bitmap.h>
 #include <linux/debugfs.h>
 #include <linux/scatterlist.h>
 #include <linux/dma-mapping.h>
@@ -959,7 +959,7 @@ static void dma_ops_free_addresses(struct dma_ops_domain *dom,
 
 	address = (address % APERTURE_RANGE_SIZE) >> PAGE_SHIFT;
 
-	iommu_area_free(range->bitmap, address, pages);
+	bitmap_clear(range->bitmap, address, pages);
 
 }
 
diff --git a/arch/x86/kernel/pci-calgary_64.c b/arch/x86/kernel/pci-calgary_64.c
index 971a3be..c87bb20 100644
--- a/arch/x86/kernel/pci-calgary_64.c
+++ b/arch/x86/kernel/pci-calgary_64.c
@@ -31,7 +31,7 @@
 #include <linux/string.h>
 #include <linux/crash_dump.h>
 #include <linux/dma-mapping.h>
-#include <linux/bitops.h>
+#include <linux/bitmap.h>
 #include <linux/pci_ids.h>
 #include <linux/pci.h>
 #include <linux/delay.h>
@@ -211,7 +211,7 @@ static void iommu_range_reserve(struct iommu_table *tbl,
 
 	spin_lock_irqsave(&tbl->it_lock, flags);
 
-	iommu_area_reserve(tbl->it_map, index, npages);
+	bitmap_set(tbl->it_map, index, npages);
 
 	spin_unlock_irqrestore(&tbl->it_lock, flags);
 }
@@ -305,7 +305,7 @@ static void iommu_free(struct iommu_table *tbl, dma_addr_t dma_addr,
 
 	spin_lock_irqsave(&tbl->it_lock, flags);
 
-	iommu_area_free(tbl->it_map, entry, npages);
+	bitmap_clear(tbl->it_map, entry, npages);
 
 	spin_unlock_irqrestore(&tbl->it_lock, flags);
 }
diff --git a/arch/x86/kernel/pci-gart_64.c b/arch/x86/kernel/pci-gart_64.c
index a7f1b64..156e362 100644
--- a/arch/x86/kernel/pci-gart_64.c
+++ b/arch/x86/kernel/pci-gart_64.c
@@ -23,7 +23,7 @@
 #include <linux/module.h>
 #include <linux/topology.h>
 #include <linux/interrupt.h>
-#include <linux/bitops.h>
+#include <linux/bitmap.h>
 #include <linux/kdebug.h>
 #include <linux/scatterlist.h>
 #include <linux/iommu-helper.h>
@@ -123,7 +123,7 @@ static void free_iommu(unsigned long offset, int size)
 	unsigned long flags;
 
 	spin_lock_irqsave(&iommu_bitmap_lock, flags);
-	iommu_area_free(iommu_gart_bitmap, offset, size);
+	bitmap_clear(iommu_gart_bitmap, offset, size);
 	if (offset >= next_bit)
 		next_bit = offset + size;
 	spin_unlock_irqrestore(&iommu_bitmap_lock, flags);
@@ -782,7 +782,7 @@ void __init gart_iommu_init(void)
 	 * Out of IOMMU space handling.
 	 * Reserve some invalid pages at the beginning of the GART.
 	 */
-	iommu_area_reserve(iommu_gart_bitmap, 0, EMERGENCY_PAGES);
+	bitmap_set(iommu_gart_bitmap, 0, EMERGENCY_PAGES);
 
 	agp_memory_reserved = iommu_size;
 	printk(KERN_INFO
diff --git a/include/linux/iommu-helper.h b/include/linux/iommu-helper.h
index 3b068e5..64d1b63 100644
--- a/include/linux/iommu-helper.h
+++ b/include/linux/iommu-helper.h
@@ -14,14 +14,11 @@ static inline unsigned long iommu_device_max_index(unsigned long size,
 extern int iommu_is_span_boundary(unsigned int index, unsigned int nr,
 				  unsigned long shift,
 				  unsigned long boundary_size);
-extern void iommu_area_reserve(unsigned long *map, unsigned long i, int len);
 extern unsigned long iommu_area_alloc(unsigned long *map, unsigned long size,
 				      unsigned long start, unsigned int nr,
 				      unsigned long shift,
 				      unsigned long boundary_size,
 				      unsigned long align_mask);
-extern void iommu_area_free(unsigned long *map, unsigned long start,
-			    unsigned int nr);
 
 extern unsigned long iommu_num_pages(unsigned long addr, unsigned long len,
 				     unsigned long io_page_size);
diff --git a/lib/iommu-helper.c b/lib/iommu-helper.c
index 75dbda0..c0251f4 100644
--- a/lib/iommu-helper.c
+++ b/lib/iommu-helper.c
@@ -3,41 +3,7 @@
  */
 
 #include <linux/module.h>
-#include <linux/bitops.h>
-
-static unsigned long find_next_zero_area(unsigned long *map,
-					 unsigned long size,
-					 unsigned long start,
-					 unsigned int nr,
-					 unsigned long align_mask)
-{
-	unsigned long index, end, i;
-again:
-	index = find_next_zero_bit(map, size, start);
-
-	/* Align allocation */
-	index = (index + align_mask) & ~align_mask;
-
-	end = index + nr;
-	if (end >= size)
-		return -1;
-	for (i = index; i < end; i++) {
-		if (test_bit(i, map)) {
-			start = i+1;
-			goto again;
-		}
-	}
-	return index;
-}
-
-void iommu_area_reserve(unsigned long *map, unsigned long i, int len)
-{
-	unsigned long end = i + len;
-	while (i < end) {
-		__set_bit(i, map);
-		i++;
-	}
-}
+#include <linux/bitmap.h>
 
 int iommu_is_span_boundary(unsigned int index, unsigned int nr,
 			   unsigned long shift,
@@ -55,31 +21,24 @@ unsigned long iommu_area_alloc(unsigned long *map, unsigned long size,
 			       unsigned long align_mask)
 {
 	unsigned long index;
+
+	/* We don't want the last of the limit */
+	size -= 1;
 again:
-	index = find_next_zero_area(map, size, start, nr, align_mask);
-	if (index != -1) {
+	index = bitmap_find_next_zero_area(map, size, start, nr, align_mask);
+	if (index < size) {
 		if (iommu_is_span_boundary(index, nr, shift, boundary_size)) {
 			/* we could do more effectively */
 			start = index + 1;
 			goto again;
 		}
-		iommu_area_reserve(map, index, nr);
+		bitmap_set(map, index, nr);
+		return index;
 	}
-	return index;
+	return -1;
 }
 EXPORT_SYMBOL(iommu_area_alloc);
 
-void iommu_area_free(unsigned long *map, unsigned long start, unsigned int nr)
-{
-	unsigned long end = start + nr;
-
-	while (start < end) {
-		__clear_bit(start, map);
-		start++;
-	}
-}
-EXPORT_SYMBOL(iommu_area_free);
-
 unsigned long iommu_num_pages(unsigned long addr, unsigned long len,
 			      unsigned long io_page_size)
 {
-- 
1.6.5.1

Re: [PATCH 1/7] bitmap: Introduce bitmap_set, bitmap_clear, bitmap_find_next_zero_area

[Andrew Morton]

Why were these patches resent?  What changed?

Everybody who is going to review these patches has already reviewed
them and now they need to review them all again?

Re: [PATCH 1/7] bitmap: Introduce bitmap_set, bitmap_clear, bitmap_find_next_zero_area

[Akinobu Mita]

2009/10/29 Andrew Morton <akpm@linux-foundation.org>:
>
> Why were these patches resent? =A0What changed?
>
> Everybody who is going to review these patches has already reviewed
> them and now they need to review them all again?

I resent the patches because the iommu-helper change was not correct
and I introduced serious bug in bitmap_find_next_zero_area()
if align_mask !=3D 0 in follow-up patch then those were dropped from
the -mm tree.

Only [PATCH 1/7] and [PATCH 2/7] have changes since the first submission of
this patch set.

* [PATCH 1/7]
- Rewrite bitmap_set() and bitmap_clear()
- Let bitmap_find_next_zero_area() check the last bit of the limit
- Add kerneldoc for bitmap_find_next_zero_area()

* [PATCH 2/7]
- Convert find_next_zero_area() to use bitmap_find_next_zero_area() correct=
ly
  iommu-helper doesn't want to search the last bit of the limist in bitmap

* [PATCH 3/7] - [PATCH 7/7]
- No changes