The SHM_HUGE_* stuff was introduced in: 42d7395feb5 (mm: support more pagesizes for MAP_HUGETLB/SHM_HUGETLB)
It unnecessarily adds another layer, specific to sysv shm, without anything special about it: the macros are identical to the MAP_HUGE_* stuff, which in turn does correctly describe the hugepage subsystem. One example of the problems with extra layers what this patch fixes: mmap_pgoff() should never be using SHM_HUGE_* logic. This was introduced by: 091d0d55b28 (shm: fix null pointer deref when userspace specifies invalid hugepage size) It is obviously harmless but lets just rip out the whole thing -- the shmget.2 manpage will need updating, as it should not be describing kernel internals. Signed-off-by: Davidlohr Bueso <[email protected]> --- include/linux/shm.h | 13 ------------- ipc/shm.c | 6 +++--- mm/mmap.c | 2 +- tools/testing/selftests/vm/thuge-gen.c | 8 +------- 4 files changed, 5 insertions(+), 24 deletions(-) diff --git a/include/linux/shm.h b/include/linux/shm.h index 429c1995d756..98fc25f9db8a 100644 --- a/include/linux/shm.h +++ b/include/linux/shm.h @@ -31,19 +31,6 @@ struct shmid_kernel /* private to the kernel */ /* Bits [26:31] are reserved */ -/* - * When SHM_HUGETLB is set bits [26:31] encode the log2 of the huge page size. - * This gives us 6 bits, which is enough until someone invents 128 bit address - * spaces. - * - * Assume these are all power of twos. - * When 0 use the default page size. - */ -#define SHM_HUGE_SHIFT 26 -#define SHM_HUGE_MASK 0x3f -#define SHM_HUGE_2MB (21 << SHM_HUGE_SHIFT) -#define SHM_HUGE_1GB (30 << SHM_HUGE_SHIFT) - #ifdef CONFIG_SYSVIPC long do_shmat(int shmid, char __user *shmaddr, int shmflg, unsigned long *addr, unsigned long shmlba); diff --git a/ipc/shm.c b/ipc/shm.c index 7e199fa1960f..f21a2338ee39 100644 --- a/ipc/shm.c +++ b/ipc/shm.c @@ -491,8 +491,8 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params) sprintf (name, "SYSV%08x", key); if (shmflg & SHM_HUGETLB) { - struct hstate *hs = hstate_sizelog((shmflg >> SHM_HUGE_SHIFT) - & SHM_HUGE_MASK); + struct hstate *hs = hstate_sizelog((shmflg >> MAP_HUGE_SHIFT) + & MAP_HUGE_MASK); size_t hugesize; if (!hs) { @@ -506,7 +506,7 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params) acctflag = VM_NORESERVE; file = hugetlb_file_setup(name, hugesize, acctflag, &shp->mlock_user, HUGETLB_SHMFS_INODE, - (shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK); + (shmflg >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK); } else { /* * Do not allow no accounting for OVERCOMMIT_NEVER, even diff --git a/mm/mmap.c b/mm/mmap.c index 0718c175db8f..a1c4cefc5a38 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1369,7 +1369,7 @@ SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len, } else if (flags & MAP_HUGETLB) { struct user_struct *user = NULL; struct hstate *hs = hstate_sizelog((flags >> MAP_HUGE_SHIFT) & - SHM_HUGE_MASK); + MAP_HUGE_MASK); if (!hs) return -EINVAL; diff --git a/tools/testing/selftests/vm/thuge-gen.c b/tools/testing/selftests/vm/thuge-gen.c index c87957295f74..4479015ec96a 100644 --- a/tools/testing/selftests/vm/thuge-gen.c +++ b/tools/testing/selftests/vm/thuge-gen.c @@ -32,12 +32,6 @@ #define MAP_HUGE_MASK 0x3f #define MAP_HUGETLB 0x40000 -#define SHM_HUGETLB 04000 /* segment will use huge TLB pages */ -#define SHM_HUGE_SHIFT 26 -#define SHM_HUGE_MASK 0x3f -#define SHM_HUGE_2MB (21 << SHM_HUGE_SHIFT) -#define SHM_HUGE_1GB (30 << SHM_HUGE_SHIFT) - #define NUM_PAGESIZES 5 #define NUM_PAGES 4 @@ -243,7 +237,7 @@ int main(void) for (i = 0; i < num_page_sizes; i++) { unsigned long ps = page_sizes[i]; - int arg = ilog2(ps) << SHM_HUGE_SHIFT; + int arg = ilog2(ps) << MAP_HUGE_SHIFT; printf("Testing %luMB shmget with shift %x\n", ps >> 20, arg); test_shmget(ps, SHM_HUGETLB | arg); } -- 2.6.6
