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| author | sephe <sephe@FreeBSD.org> | 2016-02-26 02:26:19 +0000 |
|---|---|---|
| committer | sephe <sephe@FreeBSD.org> | 2016-02-26 02:26:19 +0000 |
| commit | 90988c1816c4c962221da2b8a89714543b6d9392 (patch) | |
| tree | 8bd5a434449dd7cc92b434d25568f30ef304929b | |
| parent | 91180d20bc4ef6dc63633bb8b84e5c3f27515275 (diff) | |
| download | FreeBSD-src-90988c1816c4c962221da2b8a89714543b6d9392.zip FreeBSD-src-90988c1816c4c962221da2b8a89714543b6d9392.tar.gz | |
hyperv: Use atomic_fetchadd_int to get GPADL id.
Reviewed by: Hongjiang Zhang <honzhan microsoft com>
MFC after: 1 week
Sponsored by: Microsoft OSTC
Differential Revision: https://reviews.freebsd.org/D5439
| -rw-r--r-- | sys/dev/hyperv/vmbus/hv_channel.c | 19 |
1 files changed, 12 insertions, 7 deletions
diff --git a/sys/dev/hyperv/vmbus/hv_channel.c b/sys/dev/hyperv/vmbus/hv_channel.c index bb777cc..a9b7bd4 100644 --- a/sys/dev/hyperv/vmbus/hv_channel.c +++ b/sys/dev/hyperv/vmbus/hv_channel.c @@ -384,17 +384,22 @@ hv_vmbus_channel_establish_gpadl( hv_vmbus_channel_msg_info* curr; uint32_t next_gpadl_handle; - next_gpadl_handle = hv_vmbus_g_connection.next_gpadl_handle; - atomic_add_int((int*) &hv_vmbus_g_connection.next_gpadl_handle, 1); + next_gpadl_handle = atomic_fetchadd_int( + &hv_vmbus_g_connection.next_gpadl_handle, 1); ret = vmbus_channel_create_gpadl_header( contig_buffer, size, &msg_info, &msg_count); - if(ret != 0) { /* if(allocation failed) return immediately */ - /* reverse atomic_add_int above */ - atomic_subtract_int((int*) - &hv_vmbus_g_connection.next_gpadl_handle, 1); - return ret; + if(ret != 0) { + /* + * XXX + * We can _not_ even revert the above incremental, + * if multiple GPADL establishments are running + * parallelly, decrement the global next_gpadl_handle + * is calling for _big_ trouble. A better solution + * is to have a 0-based GPADL id bitmap ... + */ + return ret; } sema_init(&msg_info->wait_sema, 0, "Open Info Sema"); |
