On Wed, May 14, 2003 at 02:40:09AM +0200, axel@pearbough.net wrote:
> today compiled 2.5.69-bk8 with gcc version 3.3 20030510 and a warning in
> drivers/scsi/aic7xxx/aic7xxx_osm.c resulted in an error because of gcc flag
> -Werror.
I can't reproduce this with gcc-3.2; does this do better?
I also removed some extremely fishy arithmetic in a check for crossing
4GB boundaries; I hope you don't mind.
-- wli
diff -prauN linux-2.5.69-bk8-1/drivers/scsi/aic7xxx/aic7xxx_osm.c linux-2.5.69-bk8-2/drivers/scsi/aic7xxx/aic7xxx_osm.c
--- linux-2.5.69-bk8-1/drivers/scsi/aic7xxx/aic7xxx_osm.c 2003-05-13 17:26:56.000000000 -0700
+++ linux-2.5.69-bk8-2/drivers/scsi/aic7xxx/aic7xxx_osm.c 2003-05-13 19:56:26.000000000 -0700
@@ -744,18 +744,20 @@ ahc_linux_map_seg(struct ahc_softc *ahc,
"Increase AHC_NSEG\n");
consumed = 1;
- sg->addr = ahc_htole32(addr & 0xFFFFFFFF);
+ sg->addr = ahc_htole32(addr & ~0U);
scb->platform_data->xfer_len += len;
- if (sizeof(bus_addr_t) > 4
- && (ahc->flags & AHC_39BIT_ADDRESSING) != 0) {
+ if (sizeof(bus_addr_t) > 4 &&
+ (ahc->flags & AHC_39BIT_ADDRESSING) != 0) {
/*
- * Due to DAC restrictions, we can't
- * cross a 4GB boundary.
+ * Due to DAC restrictions, we can't cross 4GB boundaries.
+ * Right shift by 30 to find GB-granularity placement
+ * without getting tripped up by anal compilers.
*/
- if ((addr ^ (addr + len - 1)) & ~0xFFFFFFFF) {
+ if ((addr >> 30) < 4 && ((addr + len - 1) >> 30) >= 4) {
struct ahc_dma_seg *next_sg;
uint32_t next_len;
+ /* somebody clean this up to return an error */
printf("Crossed Seg\n");
if ((scb->sg_count + 2) > AHC_NSEG)
panic("Too few segs for dma mapping. "
@@ -764,12 +766,22 @@ ahc_linux_map_seg(struct ahc_softc *ahc,
consumed++;
next_sg = sg + 1;
next_sg->addr = 0;
- next_len = 0x100000000 - (addr & 0xFFFFFFFF);
+
+ /*
+ * 2's complement arithmetic assumed.
+ * We want: 4GB - low 32 bits of addr
+ * to find the length of the low segment
+ * and to subtract it out from the high
+ */
+ next_len = -((uint32_t)addr);
len -= next_len;
- next_len |= ((addr >> 8) + 0x1000000) & 0x7F000000;
+
+ /* c.f. struct ahc_dma_seg for meaning of high byte */
+ next_len |= ((addr >> 8) + AHC_SG_LEN_MASK + 1)
+ & AHC_SG_HIGH_ADDR_MASK;
next_sg->len = ahc_htole32(next_len);
}
- len |= (addr >> 8) & 0x7F000000;
+ len |= (addr >> 8) & AHC_SG_HIGH_ADDR_MASK;
}
sg->len = ahc_htole32(len);
return (consumed);
-
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This archive was generated by hypermail 2b29 : Thu May 15 2003 - 22:00:50 EST