* Re: [PATCH] simscsi breakage in __scsi_alloc_queue()
2012-05-04 3:53 ` [PATCH] simscsi breakage in __scsi_alloc_queue() Al Viro
@ 2012-05-04 9:40 ` James Bottomley
0 siblings, 0 replies; 2+ messages in thread
From: James Bottomley @ 2012-05-04 9:40 UTC (permalink / raw)
To: Al Viro; +Cc: Tony Luck, linux-scsi@vger.kernel.org, Lin Ming
On Fri, 2012-05-04 at 04:53 +0100, Al Viro wrote:
> With the current mainline we end up oopsing in __scsi_alloc_queue(), since
> host->dma_dev is left NULL. I'm not sure if this is the right fix, but
> it gives the behaviour equivalent to what we used to have before
> commit 6f381fa344911d5a234b13574433cf23036f9467 ([SCSI] scsi_lib: use
> correct DMA device in __scsi_alloc_queue). And with that applied the
> damn thing appears to work correctly...
>
> Current mainline barfs on dma_set_seg_boundary(dev, shost->dma_boundary),
> since dev ends up being NULL. AFAICS, the same problem affects any
> driver that does scsi_add_host(host, NULL) and there are other such
> beasts as well, so they probably also need fixing...
>
> Again, I'm not sure that this is the right way to deal with that and I'd
> prefer to have it reviewed by SCSI folks before it goes into the tree.
>
> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
> ---
> diff --git a/arch/ia64/hp/sim/simscsi.c b/arch/ia64/hp/sim/simscsi.c
> index 331de72..fe2b4d0 100644
> --- a/arch/ia64/hp/sim/simscsi.c
> +++ b/arch/ia64/hp/sim/simscsi.c
> @@ -13,6 +13,7 @@
> #include <linux/interrupt.h>
> #include <linux/kernel.h>
> #include <linux/timer.h>
> +#include <linux/platform_device.h>
> #include <asm/irq.h>
> #include "hpsim_ssc.h"
>
> @@ -358,7 +359,7 @@ simscsi_init(void)
> if (!host)
> return -ENOMEM;
>
> - error = scsi_add_host(host, NULL);
> + error = scsi_add_host_with_dma(host, NULL, &platform_bus);
It's the right fix, but it's not general enough. This should make sure
none of the legacy bus devices oops:
James
---
diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
index 351dc0b..a3a056a 100644
--- a/drivers/scsi/hosts.c
+++ b/drivers/scsi/hosts.c
@@ -218,6 +218,9 @@ int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
if (!shost->shost_gendev.parent)
shost->shost_gendev.parent = dev ? dev : &platform_bus;
+ if (!dma_dev)
+ dma_dev = shost->shost_gendev.parent;
+
shost->dma_dev = dma_dev;
error = device_add(&shost->shost_gendev);
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