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drbd: drbd_bitmap: Avoid name collision

PATCH In review Fabio Estevam 2 participants 3 messages Mar 10, 2015 – Mar 12, 2015

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Block layer DRBD driver
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Fabio Estevam

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#0 lore raw

PATCH 1/1 drbd: drbd_bitmap: Avoid name collision

From: Fabio Estevam <[email protected]>

Building for ARM64 leads to the following build warnings:

CC drivers/block/drbd/drbd_bitmap.o
drivers/block/drbd/drbd_bitmap.c:483:0: warning: "BITS_PER_PAGE" redefined
#define BITS_PER_PAGE (1UL << (PAGE_SHIFT + 3))
^
In file included from include/linux/ptrace.h:8:0,

                 from ./arch/arm64/include/asm/compat.h:26,
                 from ./arch/arm64/include/asm/stat.h:23,
                 from include/linux/stat.h:5,
                 from include/linux/sysfs.h:21,
                 from include/linux/kobject.h:21,
                 from include/linux/device.h:17,
                 from include/linux/pm_qos.h:10,
                 from include/linux/netdevice.h:28,
                 from include/net/sock.h:51,
                 from include/linux/connector.h:30,
                 from include/linux/drbd.h:28,
                 from drivers/block/drbd/drbd_bitmap.c:30:

include/linux/pid_namespace.h:18:0: note: this is the location of the previous definition
#define BITS_PER_PAGE (PAGE_SIZE * 8)
^
drivers/block/drbd/drbd_bitmap.c:484:0: warning: "BITS_PER_PAGE_MASK" redefined
#define BITS_PER_PAGE_MASK (BITS_PER_PAGE - 1)
^
In file included from include/linux/ptrace.h:8:0,

                 from ./arch/arm64/include/asm/compat.h:26,
                 from ./arch/arm64/include/asm/stat.h:23,
                 from include/linux/stat.h:5,
                 from include/linux/sysfs.h:21,
                 from include/linux/kobject.h:21,
                 from include/linux/device.h:17,
                 from include/linux/pm_qos.h:10,
                 from include/linux/netdevice.h:28,
                 from include/net/sock.h:51,
                 from include/linux/connector.h:30,
                 from include/linux/drbd.h:28,
                 from drivers/block/drbd/drbd_bitmap.c:30:

include/linux/pid_namespace.h:19:0: note: this is the location of the previous definition
#define BITS_PER_PAGE_MASK (BITS_PER_PAGE-1)
^

Fix the warnings by using BITS_PER_PAGE_DRBD and BITS_PER_PAGE_MASK_DRBD definitions to avoid the name collision.

Reported-by Olof's autobuilder <[email protected]>
Signed-off-by Fabio Estevam <[email protected]>
---
 drivers/block/drbd/drbd_bitmap.c | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)
drivers/block/drbd/drbd_bitmap.c +11 -11
index 434c77d..b8dc9fc 100644
@@ -479,8 +479,8 @@ void drbd_bm_cleanup(struct drbd_device *device)
  * this masks out the remaining bits.
  * Returns the number of bits cleared.
  */
-#define BITS_PER_PAGE		(1UL << (PAGE_SHIFT + 3))
-#define BITS_PER_PAGE_MASK	(BITS_PER_PAGE - 1)
+#define BITS_PER_PAGE_DRBD	(1UL << (PAGE_SHIFT + 3))
+#define BITS_PER_PAGE_MASK_DRBD	(BITS_PER_PAGE_DRBD - 1)
 #define BITS_PER_LONG_MASK	(BITS_PER_LONG - 1)
 static int bm_clear_surplus(struct drbd_bitmap *b)
 {

@@ -490,7 +490,7 @@ static int bm_clear_surplus(struct drbd_bitmap *b)
 	int cleared = 0;
 
 	/* number of bits modulo bits per page */
-	tmp = (b->bm_bits & BITS_PER_PAGE_MASK);
+	tmp = (b->bm_bits & BITS_PER_PAGE_MASK_DRBD);
 	/* mask the used bits of the word containing the last bit */
 	mask = (1UL << (tmp & BITS_PER_LONG_MASK)) -1;
 	/* bitmap is always stored little endian,

@@ -526,7 +526,7 @@ static void bm_set_surplus(struct drbd_bitmap *b)
 	int tmp;
 
 	/* number of bits modulo bits per page */
-	tmp = (b->bm_bits & BITS_PER_PAGE_MASK);
+	tmp = (b->bm_bits & BITS_PER_PAGE_MASK_DRBD);
 	/* mask the used bits of the word containing the last bit */
 	mask = (1UL << (tmp & BITS_PER_LONG_MASK)) -1;
 	/* bitmap is always stored little endian,

@@ -570,7 +570,7 @@ static unsigned long bm_count_bits(struct drbd_bitmap *b)
 		cond_resched();
 	}
 	/* last (or only) page */
-	last_word = ((b->bm_bits - 1) & BITS_PER_PAGE_MASK) >> LN2_BPL;
+	last_word = ((b->bm_bits - 1) & BITS_PER_PAGE_MASK_DRBD) >> LN2_BPL;
 	p_addr = __bm_map_pidx(b, idx);
 	for (i = 0; i < last_word; i++)
 		bits += hweight_long(p_addr[i]);

@@ -1257,15 +1257,15 @@ static unsigned long __bm_find_next(struct drbd_device *device, unsigned long bm
 	} else {
 		while (bm_fo < b->bm_bits) {
 			/* bit offset of the first bit in the page */
-			bit_offset = bm_fo & ~BITS_PER_PAGE_MASK;
+			bit_offset = bm_fo & ~BITS_PER_PAGE_MASK_DRBD;
 			p_addr = __bm_map_pidx(b, bm_bit_to_page_idx(b, bm_fo));
 
 			if (find_zero_bit)
 				i = find_next_zero_bit_le(p_addr,
-						PAGE_SIZE*8, bm_fo & BITS_PER_PAGE_MASK);
+						PAGE_SIZE*8, bm_fo & BITS_PER_PAGE_MASK_DRBD);
 			else
 				i = find_next_bit_le(p_addr,
-						PAGE_SIZE*8, bm_fo & BITS_PER_PAGE_MASK);
+						PAGE_SIZE*8, bm_fo & BITS_PER_PAGE_MASK_DRBD);
 
 			__bm_unmap(p_addr);
 			if (i < PAGE_SIZE*8) {

@@ -1366,9 +1366,9 @@ static int __bm_change_bits_to(struct drbd_device *device, const unsigned long s
 			last_page_nr = page_nr;
 		}
 		if (val)
-			c += (0 == __test_and_set_bit_le(bitnr & BITS_PER_PAGE_MASK, p_addr));
+			c += (0 == __test_and_set_bit_le(bitnr & BITS_PER_PAGE_MASK_DRBD, p_addr));
 		else
-			c -= (0 != __test_and_clear_bit_le(bitnr & BITS_PER_PAGE_MASK, p_addr));
+			c -= (0 != __test_and_clear_bit_le(bitnr & BITS_PER_PAGE_MASK_DRBD, p_addr));
 	}
 	if (p_addr)
 		__bm_unmap(p_addr);

@@ -1545,7 +1545,7 @@ int drbd_bm_test_bit(struct drbd_device *device, const unsigned long bitnr)
 		bm_print_lock_info(device);
 	if (bitnr < b->bm_bits) {
 		p_addr = bm_map_pidx(b, bm_bit_to_page_idx(b, bitnr));
-		i = test_bit_le(bitnr & BITS_PER_PAGE_MASK, p_addr) ? 1 : 0;
+		i = test_bit_le(bitnr & BITS_PER_PAGE_MASK_DRBD, p_addr) ? 1 : 0;
 		bm_unmap(p_addr);
 	} else if (bitnr == b->bm_bits) {
 		i = -1;
Signature · 1 line
1.9.1
maintainer
#1 lore raw
Quoted 7 lines · Fabio Estevam

From: Fabio Estevam <[email protected]>

Building for ARM64 leads to the following build warnings:

CC drivers/block/drbd/drbd_bitmap.o
drivers/block/drbd/drbd_bitmap.c:483:0: warning: "BITS_PER_PAGE" redefined
#define BITS_PER_PAGE (1UL << (PAGE_SHIFT + 3))

Apparently there are more than one consumer of "BITS_PER_PAGE". The commit that moved the now conflicting definition to pid_namespace.h itself already refered to a similar "redefined" warning.

Would it not make more sense to have one such definition next to PAGE_SIZE? Or somewhere central, anyways?

Quoted 2 lines

Fix the warnings by using BITS_PER_PAGE_DRBD and BITS_PER_PAGE_MASK_DRBD definitions to avoid the name collision.

Other than that:
Ack.

Lars Ellenberg

author
#2 lore raw
Quoted 6 lines · Lars Ellenberg

Apparently there are more than one consumer of "BITS_PER_PAGE". The commit that moved the now conflicting definition to pid_namespace.h itself already refered to a similar "redefined" warning.

Would it not make more sense to have one such definition next to PAGE_SIZE? Or somewhere central, anyways?

What about this instead?

drivers/block/drbd/drbd_bitmap.c +1 -2
@@ -29,6 +29,7 @@
 #include <linux/string.h>
 #include <linux/drbd.h>
 #include <linux/slab.h>
+#include <linux/pid_namespace.h>
 #include <asm/kmap_types.h>
 
 #include "drbd_int.h"

@@ -479,8 +480,6 @@ void drbd_bm_cleanup(struct drbd_device *device)
  * this masks out the remaining bits.
  * Returns the number of bits cleared.
  */
-#define BITS_PER_PAGE          (1UL << (PAGE_SHIFT + 3))
-#define BITS_PER_PAGE_MASK     (BITS_PER_PAGE - 1)
 #define BITS_PER_LONG_MASK     (BITS_PER_LONG - 1)
 static int bm_clear_surplus(struct drbd_bitmap *b)
 {