MIPS: Fix logic errors in bitops.c

commit 92d11594f6 (MIPS: Remove irqflags.h dependency from bitops.h)
factored some of the bitops code out into a separate file
(arch/mips/lib/bitops.c).  Unfortunately the logic converting a bit
mask into a boolean result was lost in some of the functions.  We had:

   int res;
   unsigned long shifted_result_bit;
   .
   .
   .
   res = shifted_result_bit;
   return res;

Which truncates off the high 32 bits (thus yielding an incorrect
value) on 64-bit systems.

The manifestation of this is that a non-SMP 64-bit kernel will not
boot as the bitmap operations in bootmem.c are all screwed up.

Signed-off-by: David Daney <david.daney@cavium.com>
Cc:  linux-mips@linux-mips.org
Cc: Jim Quinlan <jim2101024@gmail.com>
Cc: stable@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/4965/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

diff --git a/arch/mips/lib/bitops.c b/arch/mips/lib/bitops.c
index 81f1dcfdcab8c212ebbac6c5159291dc8b8e1162..a64daee740ee0414ee6a8db474b32893ae51ab1d 100644 (file)
--- a/arch/mips/lib/bitops.c
+++ b/arch/mips/lib/bitops.c
@@ -90,12 +90,12 @@ int __mips_test_and_set_bit(unsigned long nr,
        unsigned bit = nr & SZLONG_MASK;
        unsigned long mask;
        unsigned long flags;
-       unsigned long res;
+       int res;
 
        a += nr >> SZLONG_LOG;
        mask = 1UL << bit;
        raw_local_irq_save(flags);
-       res = (mask & *a);
+       res = (mask & *a) != 0;
        *a |= mask;
        raw_local_irq_restore(flags);
        return res;
@@ -116,12 +116,12 @@ int __mips_test_and_set_bit_lock(unsigned long nr,
        unsigned bit = nr & SZLONG_MASK;
        unsigned long mask;
        unsigned long flags;
-       unsigned long res;
+       int res;
 
        a += nr >> SZLONG_LOG;
        mask = 1UL << bit;
        raw_local_irq_save(flags);
-       res = (mask & *a);
+       res = (mask & *a) != 0;
        *a |= mask;
        raw_local_irq_restore(flags);
        return res;
@@ -141,12 +141,12 @@ int __mips_test_and_clear_bit(unsigned long nr, volatile unsigned long *addr)
        unsigned bit = nr & SZLONG_MASK;
        unsigned long mask;
        unsigned long flags;
-       unsigned long res;
+       int res;
 
        a += nr >> SZLONG_LOG;
        mask = 1UL << bit;
        raw_local_irq_save(flags);
-       res = (mask & *a);
+       res = (mask & *a) != 0;
        *a &= ~mask;
        raw_local_irq_restore(flags);
        return res;
@@ -166,12 +166,12 @@ int __mips_test_and_change_bit(unsigned long nr, volatile unsigned long *addr)
        unsigned bit = nr & SZLONG_MASK;
        unsigned long mask;
        unsigned long flags;
-       unsigned long res;
+       int res;
 
        a += nr >> SZLONG_LOG;
        mask = 1UL << bit;
        raw_local_irq_save(flags);
-       res = (mask & *a);
+       res = (mask & *a) != 0;
        *a ^= mask;
        raw_local_irq_restore(flags);
        return res;