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Diffstat (limited to 'ipc/ipc_kmsg.h')
| -rw-r--r-- | ipc/ipc_kmsg.h | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/ipc/ipc_kmsg.h b/ipc/ipc_kmsg.h index 45e174b7..9ee1aa4a 100644 --- a/ipc/ipc_kmsg.h +++ b/ipc/ipc_kmsg.h @@ -156,6 +156,16 @@ MACRO_END #define ikm_alloc(size) \ ((ipc_kmsg_t) kalloc(ikm_plus_overhead(size))) +/* + * The conversion between userland and kernel-land has to convert from port + * names to ports. This may increase the size that needs to be allocated + * on the kernel size. At worse the message is full of port names to be + * converted. + */ +#define IKM_EXPAND_FACTOR ((sizeof(mach_port_t) + sizeof(mach_port_name_t) - 1) / sizeof(mach_port_name_t)) +/* But make sure it's not the converse. */ +_Static_assert(sizeof(mach_port_t) >= sizeof(mach_port_name_t)); + #define ikm_init(kmsg, size) \ MACRO_BEGIN \ ikm_init_special((kmsg), ikm_plus_overhead(size)); \ |