Turn the panic on not being able to meet alignment constraints

in bus_dmamem_alloc into the more reasonable EINVAL return.

Also, reclaim memory allocated but then not used if we had
an error return.

1 files changed, 22 insertions, 4 deletions

diff --git a/sys/amd64/amd64/busdma_machdep.c b/sys/amd64/amd64/busdma_machdep.c
index 20dae8a..e04ff39 100644
--- a/sys/amd64/amd64/busdma_machdep.c
+++ b/sys/amd64/amd64/busdma_machdep.c
@@ -469,7 +469,7 @@ int
 bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
 		 bus_dmamap_t *mapp)
 {
-	int mflags;
+	int mflags, malloc_used, swasnull = 0;
 
 	if (flags & BUS_DMA_NOWAIT)
 		mflags = M_NOWAIT;
@@ -490,6 +490,7 @@ bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
 			    __func__, dmat, dmat->flags, ENOMEM);
 			return (ENOMEM);
 		}
+		swasnull = 1;
 	}
 
 	/* 
@@ -498,12 +499,13 @@ bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
 	 * alignment guarantees of malloc need to be nailed down, and the
 	 * code below should be rewritten to take that into account.
 	 *
-	 * In the meantime, we'll panic if malloc gets it wrong.
+	 * In the meantime, we'll return an error if malloc gets it wrong.
 	 */
 	if ((dmat->maxsize <= PAGE_SIZE) &&
 	   (dmat->alignment < dmat->maxsize) &&
 	    dmat->lowaddr >= ptoa((vm_paddr_t)Maxmem)) {
 		*vaddr = malloc(dmat->maxsize, M_DEVBUF, mflags);
+		malloc_used = 1;
 	} else {
 		/*
 		 * XXX Use Contigmalloc until it is merged into this facility
@@ -514,13 +516,29 @@ bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
 		*vaddr = contigmalloc(dmat->maxsize, M_DEVBUF, mflags,
 		    0ul, dmat->lowaddr, dmat->alignment? dmat->alignment : 1ul,
 		    dmat->boundary);
+		malloc_used = 0;
 	}
 	if (*vaddr == NULL) {
+		if (swasnull) {
+			free(dmat->segments, M_DEVBUF);
+			dmat->segments = NULL;
+		}
 		CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
 		    __func__, dmat, dmat->flags, ENOMEM);
 		return (ENOMEM);
-	} else if ((uintptr_t)*vaddr & (dmat->alignment - 1)) {
-		panic("bus_dmamem_alloc failed to align memory properly.");
+	}
+	if ((uintptr_t)*vaddr & (dmat->alignment - 1)) {
+		printf("bus_dmamem_alloc failed to align memory properly.");
+		if (malloc_used) {
+			free(*vaddr, M_DEVBUF);
+		} else {
+			contigfree(*vaddr, dmat->maxsize, M_DEVBUF);
+		}
+		if (swasnull) {
+			free(dmat->segments, M_DEVBUF);
+			dmat->segments = NULL;
+		}
+		return (EINVAL);
 	}
 	CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
 	    __func__, dmat, dmat->flags, ENOMEM);