linux-kernel - Re: [PATCH 10/10] xen/swiotlb: Depending on after

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Message-ID: <20120917142315.GA12541@phenom.dumpdata.com>
Date:	Mon, 17 Sep 2012 10:23:15 -0400
From:	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
To:	Stefano Stabellini <stefano.stabellini@...citrix.com>
Cc:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"xen-devel@...ts.xensource.com" <xen-devel@...ts.xensource.com>
Subject: Re: [PATCH 10/10] xen/swiotlb: Depending on after_bootmem is not
 correct.

> >  	start_dma_addr = xen_virt_to_bus(xen_io_tlb_start);
> > -	if (!after_bootmem)
> > +	rc = 0;
>      ^
> why does this change belong to this patch?
> 
> 

I took that out of the this patch, so it is now:


>From c5bc5502abc0f70b682c0f2a70d08e6319825163 Mon Sep 17 00:00:00 2001
From: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
Date: Wed, 5 Sep 2012 13:35:47 -0400
Subject: [PATCH 1/2] xen/swiotlb: Depending on after_bootmem is not correct.

When PCI IOMMUs are initialized it is after after_bootmem but
before a lot of "other" subsystems are initialized. As such
the check for after_bootmem is incorrect and we should
just use a parameter to define whether we are early or late.

This solves this bootup problem:

__ex_table already sorted, skipping sortM
Initializing CPU#0
Warning: only able to allocate 1 MB for software IO TLB
Xen-SWIOTLB: Lowering to 2MB
Warning: only able to allocate 1 MB for software IO TLB
Xen-SWIOTLB: Lowering to 2MB
Warning: only able to allocate 1 MB for software IO TLB
Xen-SWIOTLB: Lowering to 2MB
Warning: only able to allocate 1 MB for software IO TLB
Cannot allocate Xen-SWIOTLB buffer (rc:-12)

[v1: Had rc=0 in it by mistake]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
---
 arch/x86/xen/pci-swiotlb-xen.c |    4 ++--
 drivers/xen/swiotlb-xen.c      |   10 +++++-----
 include/xen/swiotlb-xen.h      |    2 +-
 3 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/arch/x86/xen/pci-swiotlb-xen.c b/arch/x86/xen/pci-swiotlb-xen.c
index fc0c78f..1608244 100644
--- a/arch/x86/xen/pci-swiotlb-xen.c
+++ b/arch/x86/xen/pci-swiotlb-xen.c
@@ -69,7 +69,7 @@ int __init pci_xen_swiotlb_detect(void)
 void __init pci_xen_swiotlb_init(void)
 {
 	if (xen_swiotlb) {
-		xen_swiotlb_init(1);
+		xen_swiotlb_init(1, true /* early */);
 		dma_ops = &xen_swiotlb_dma_ops;
 
 		/* Make sure ACS will be enabled */
@@ -84,7 +84,7 @@ int pci_xen_swiotlb_init_late(void)
 	if (xen_swiotlb)
 		return 0;
 
-	rc = xen_swiotlb_init(1);
+	rc = xen_swiotlb_init(1, false /* late */);
 	if (rc)
 		return rc;
 
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 6f81994..02a52f3 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -176,7 +176,7 @@ static const char *xen_swiotlb_error(enum xen_swiotlb_err err)
 	}
 	return "";
 }
-int __ref xen_swiotlb_init(int verbose)
+int __ref xen_swiotlb_init(int verbose, bool early)
 {
 	unsigned long bytes, order;
 	int rc = -ENOMEM;
@@ -190,7 +190,7 @@ retry:
 	/*
 	 * Get IO TLB memory from any location.
 	 */
-	if (!after_bootmem)
+	if (early)
 		xen_io_tlb_start = alloc_bootmem_pages(PAGE_ALIGN(bytes));
 	else {
 #define SLABS_PER_PAGE (1 << (PAGE_SHIFT - IO_TLB_SHIFT))
@@ -220,7 +220,7 @@ retry:
 			       bytes,
 			       xen_io_tlb_nslabs);
 	if (rc) {
-		if (!after_bootmem)
+		if (early)
 			free_bootmem(__pa(xen_io_tlb_start), PAGE_ALIGN(bytes));
 		else {
 			free_pages((unsigned long)xen_io_tlb_start, order);
@@ -230,7 +230,7 @@ retry:
 		goto error;
 	}
 	start_dma_addr = xen_virt_to_bus(xen_io_tlb_start);
-	if (!after_bootmem)
+	if (early)
 		swiotlb_init_with_tbl(xen_io_tlb_start, xen_io_tlb_nslabs, verbose);
 	else
 		rc = swiotlb_late_init_with_tbl(xen_io_tlb_start, xen_io_tlb_nslabs);
@@ -244,7 +244,7 @@ error:
 		goto retry;
 	}
 	pr_err("%s (rc:%d)", xen_swiotlb_error(m_ret), rc);
-	if (!after_bootmem)
+	if (early)
 		panic("%s (rc:%d)", xen_swiotlb_error(m_ret), rc);
 	else
 		free_pages((unsigned long)xen_io_tlb_start, order);
diff --git a/include/xen/swiotlb-xen.h b/include/xen/swiotlb-xen.h
index a0db2b7..de8bcc6 100644
--- a/include/xen/swiotlb-xen.h
+++ b/include/xen/swiotlb-xen.h
@@ -3,7 +3,7 @@
 
 #include <linux/swiotlb.h>
 
-extern int xen_swiotlb_init(int verbose);
+extern int xen_swiotlb_init(int verbose, bool early);
 
 extern void
 *xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
-- 
1.7.7.6

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