[PATCH] aacraid: Fix a possible sleep-under-mutex bug in aac_alloc_commands

[Jia-Ju Bai]

The driver may sleep under a mutex, and the code path is:
aac_alloc_commands [line 1223: acquire the mutex]
aac_alloc_commands [line 1227]
  bus_dmamap_create(BUS_DMA_WAITOK) [line 1250] --> may sleep

The possible fix of this bug is to replace "BUS_DMA_WAITOK" in bus_dmamap_create with "BUS_DMA_NOWAIT".

This bug is found by a static analysis tool written by myself, and it is
checked by my review of the FreeBSD code.

Signed-off-by: Jia-Ju Bai <baijiaju1990 at 163.com>
---
 sys/dev/aacraid/aacraid.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sys/dev/aacraid/aacraid.c b/sys/dev/aacraid/aacraid.c
index 42a16c42039..b0a987f5903 100644
--- a/sys/dev/aacraid/aacraid.c
+++ b/sys/dev/aacraid/aacraid.c
@@ -1247,7 +1247,7 @@ aac_alloc_commands(struct aac_softc *sc)
 		}
 		cm->cm_index = sc->total_fibs;
 
-		if ((error = bus_dmamap_create(sc->aac_buffer_dmat, 0,
+		if ((error = bus_dmamap_create(sc->aac_buffer_dmat, BUS_DMA_NOWAIT,
 					       &cm->cm_datamap)) != 0)
 			break;
 		if (sc->aac_max_fibs <= 1 || sc->aac_max_fibs - sc->total_fibs > 1)
-- 
2.13.0