diff options
| -rw-r--r-- | include/linux/mman.h | 29 | ||||
| -rw-r--r-- | mm/mmap.c | 27 |
2 files changed, 31 insertions, 25 deletions
diff --git a/include/linux/mman.h b/include/linux/mman.h index a8956f6588ad..cfb6ac61bbde 100644 --- a/include/linux/mman.h +++ b/include/linux/mman.h @@ -2,6 +2,7 @@ #define _LINUX_MMAN_H #include <linux/config.h> +#include <linux/mm.h> #include <asm/atomic.h> #include <asm/mman.h> @@ -27,4 +28,32 @@ static inline void vm_unacct_memory(long pages) vm_acct_memory(-pages); } +/* Optimisation macro. */ +#define _calc_vm_trans(x,bit1,bit2) \ + ((bit1) <= (bit2) ? ((x) & (bit1)) * ((bit2) / (bit1)) \ + : ((x) & (bit1)) / ((bit1) / (bit2))) + +/* + * Combine the mmap "prot" argument into "vm_flags" used internally. + */ +static inline unsigned long +calc_vm_prot_bits(unsigned long prot) +{ + return _calc_vm_trans(prot, PROT_READ, VM_READ ) | + _calc_vm_trans(prot, PROT_WRITE, VM_WRITE) | + _calc_vm_trans(prot, PROT_EXEC, VM_EXEC ); +} + +/* + * Combine the mmap "flags" argument into "vm_flags" used internally. + */ +static inline unsigned long +calc_vm_flag_bits(unsigned long flags) +{ + return _calc_vm_trans(flags, MAP_GROWSDOWN, VM_GROWSDOWN ) | + _calc_vm_trans(flags, MAP_DENYWRITE, VM_DENYWRITE ) | + _calc_vm_trans(flags, MAP_EXECUTABLE, VM_EXECUTABLE) | + _calc_vm_trans(flags, MAP_LOCKED, VM_LOCKED ); +} + #endif /* _LINUX_MMAN_H */ diff --git a/mm/mmap.c b/mm/mmap.c index bcc28864eab6..61c9f5ca5f82 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -136,29 +136,6 @@ out: return retval; } -/* Combine the mmap "prot" and "flags" argument into one "vm_flags" used - * internally. Essentially, translate the "PROT_xxx" and "MAP_xxx" bits - * into "VM_xxx". - */ -static inline unsigned long -calc_vm_flags(unsigned long prot, unsigned long flags) -{ -#define _trans(x,bit1,bit2) \ -((bit1==bit2)?(x&bit1):(x&bit1)?bit2:0) - - unsigned long prot_bits, flag_bits; - prot_bits = - _trans(prot, PROT_READ, VM_READ) | - _trans(prot, PROT_WRITE, VM_WRITE) | - _trans(prot, PROT_EXEC, VM_EXEC); - flag_bits = - _trans(flags, MAP_GROWSDOWN, VM_GROWSDOWN) | - _trans(flags, MAP_DENYWRITE, VM_DENYWRITE) | - _trans(flags, MAP_EXECUTABLE, VM_EXECUTABLE); - return prot_bits | flag_bits; -#undef _trans -} - #ifdef DEBUG_MM_RB static int browse_rb(struct rb_node * rb_node) { int i = 0; @@ -500,8 +477,8 @@ unsigned long do_mmap_pgoff(struct file * file, unsigned long addr, * to. we assume access permissions have been handled by the open * of the memory object, so we don't do any here. */ - vm_flags = calc_vm_flags(prot,flags) | mm->def_flags | - VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; + vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) | + mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; if (flags & MAP_LOCKED) { if (!capable(CAP_IPC_LOCK)) |