diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/port/sysv_shmem.c | 13 | ||||
| -rw-r--r-- | src/include/port/linux.h | 13 |
2 files changed, 25 insertions, 1 deletions
diff --git a/src/backend/port/sysv_shmem.c b/src/backend/port/sysv_shmem.c index b44f07c8ec5..5229ec9cf66 100644 --- a/src/backend/port/sysv_shmem.c +++ b/src/backend/port/sysv_shmem.c @@ -10,7 +10,7 @@ * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/port/sysv_shmem.c,v 1.24.2.2 2004/11/09 20:35:16 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/port/sysv_shmem.c,v 1.24.2.3 2007/07/02 20:12:21 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -209,6 +209,17 @@ PGSharedMemoryIsInUse(unsigned long id1, unsigned long id2) if (errno == EACCES) return false; /* + * Some Linux kernel versions (in fact, all of them as of July 2007) + * sometimes return EIDRM when EINVAL is correct. The Linux kernel + * actually does not have any internal state that would justify + * returning EIDRM, so we can get away with assuming that EIDRM is + * equivalent to EINVAL on that platform. + */ +#ifdef HAVE_LINUX_EIDRM_BUG + if (errno == EIDRM) + return false; +#endif + /* * Otherwise, we had better assume that the segment is in use. * The only likely case is EIDRM, which implies that the segment * has been IPC_RMID'd but there are still processes attached to it. diff --git a/src/include/port/linux.h b/src/include/port/linux.h index 159db3194f1..7c5d0fbfd7d 100644 --- a/src/include/port/linux.h +++ b/src/include/port/linux.h @@ -49,3 +49,16 @@ typedef unsigned char slock_t; #define HAS_TEST_AND_SET #endif + +/* + * As of July 2007, all known versions of the Linux kernel will sometimes + * return EIDRM for a shmctl() operation when EINVAL is correct (it happens + * when the low-order 15 bits of the supplied shm ID match the slot number + * assigned to a newer shmem segment). We deal with this by assuming that + * EIDRM means EINVAL in PGSharedMemoryIsInUse(). This is reasonably safe + * since in fact Linux has no excuse for ever returning EIDRM; it doesn't + * track removed segments in a way that would allow distinguishing them from + * private ones. But someday that code might get upgraded, and we'd have + * to have a kernel version test here. + */ +#define HAVE_LINUX_EIDRM_BUG |