diff options
| author | Konstantin Belousov <kib@FreeBSD.org> | 2026-08-19 02:27:46 +0000 |
|---|---|---|
| committer | Konstantin Belousov <kib@FreeBSD.org> | 2026-08-19 14:46:34 +0000 |
| commit | 3a1bf59d195ced99c0f69774969d7090d21f6097 (patch) | |
| tree | 2eaa399e496facbd8231fe1cae00dc4608946821 | |
| parent | 805c5004fa86e26486175cd3a0bb253dcb8ec7e0 (diff) | |
shmfd: consistently return size in 512 byte blocks for fstat(2) st_blocks
This is ABI-breaking change that could be considered as the bug fix.
Requested by: David Timber <dxdt@dev.snart.me>
Reviewed by: emaste, markj
Sponsored by: The FreeBSD Foundation
Relnotes: yes
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D58942
| -rw-r--r-- | lib/libsys/stat.2 | 8 | ||||
| -rw-r--r-- | sys/kern/uipc_shm.c | 8 |
2 files changed, 8 insertions, 8 deletions
diff --git a/lib/libsys/stat.2 b/lib/libsys/stat.2 index c16af32a340d..bbec876da1fd 100644 --- a/lib/libsys/stat.2 +++ b/lib/libsys/stat.2 @@ -271,10 +271,14 @@ be zero. .Pp For file descriptors referencing specific non-file objects, the field is type-specific. +.Pp For POSIX shared memory segments .Pq see Xr shm_open 2 , -the block size is equal to -the platform page size +the block size is 512 bytes. +For older versions of +.Fx +.Pq before 15.2 and 16.0 +the block size was equal to the platform page size .Pq Xr getpagesize 2 . .El .Pp diff --git a/sys/kern/uipc_shm.c b/sys/kern/uipc_shm.c index 8341364f4d16..04b6f4f6e07a 100644 --- a/sys/kern/uipc_shm.c +++ b/sys/kern/uipc_shm.c @@ -658,12 +658,8 @@ shm_stat(struct file *fp, struct stat *sb, struct ucred *active_cred) sb->st_dev = shm_dev_ino; sb->st_ino = shmfd->shm_ino; sb->st_nlink = shmfd->shm_object->ref_count; - if (shm_largepage(shmfd)) { - sb->st_blocks = shmfd->shm_object->size / - (pagesizes[shmfd->shm_lp_psind] >> PAGE_SHIFT); - } else { - sb->st_blocks = shmfd->shm_pages; - } + sb->st_blocks = ptoa(shm_largepage(shmfd) ? shmfd->shm_object->size : + shmfd->shm_pages) / DEV_BSIZE; return (0); } |