The patch titled
dma_free_coherent() needs irqs enabled (sigh)
has been added to the -mm tree. Its filename is
dma_free_coherent-needs-irqs-enabled-sigh.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: dma_free_coherent() needs irqs enabled (sigh)
From: David Brownell <david-b@xxxxxxxxxxx>
On at least ARM (and I'm told MIPS too) dma_free_coherent() has a newish
call context requirement: unlike its dma_alloc_coherent() sibling, it may
not be called with IRQs disabled. (This was new behavior on ARM as of late
2006, caused by ARM SMP updates.) This little surprise can be annoyingly
driver-visible.
Since it looks like that restriction won't be removed, this patch changes
the definition of the API to include that requirement. Also, to help catch
nonportable drivers, it updates the x86 and swiotlb versions to include the
relevant warnings. (I already observed that it trips on the
bus_reset_tasklet of the new firewire_ohci driver.)
Signed-off-by: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx>
Cc: David Miller <davem@xxxxxxxxxxxxx>
Acked-by: Russell King <rmk@xxxxxxxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/DMA-API.txt | 3 +++
arch/i386/kernel/pci-dma.c | 3 ++-
arch/x86_64/kernel/pci-dma.c | 1 +
lib/swiotlb.c | 1 +
4 files changed, 7 insertions(+), 1 deletion(-)
diff -puN arch/i386/kernel/pci-dma.c~dma_free_coherent-needs-irqs-enabled-sigh arch/i386/kernel/pci-dma.c
--- a/arch/i386/kernel/pci-dma.c~dma_free_coherent-needs-irqs-enabled-sigh
+++ a/arch/i386/kernel/pci-dma.c
@@ -62,7 +62,8 @@ void dma_free_coherent(struct device *de
{
struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
int order = get_order(size);
-
+
+ WARN_ON(irqs_disabled()); /* for portability */
if (mem && vaddr >= mem->virt_base && vaddr < (mem->virt_base + (mem->size << PAGE_SHIFT))) {
int page = (vaddr - mem->virt_base) >> PAGE_SHIFT;
diff -puN arch/x86_64/kernel/pci-dma.c~dma_free_coherent-needs-irqs-enabled-sigh arch/x86_64/kernel/pci-dma.c
--- a/arch/x86_64/kernel/pci-dma.c~dma_free_coherent-needs-irqs-enabled-sigh
+++ a/arch/x86_64/kernel/pci-dma.c
@@ -163,6 +163,7 @@ EXPORT_SYMBOL(dma_alloc_coherent);
void dma_free_coherent(struct device *dev, size_t size,
void *vaddr, dma_addr_t bus)
{
+ WARN_ON(irqs_disabled()); /* for portability */
if (dma_ops->unmap_single)
dma_ops->unmap_single(dev, bus, size, 0);
free_pages((unsigned long)vaddr, get_order(size));
diff -puN Documentation/DMA-API.txt~dma_free_coherent-needs-irqs-enabled-sigh Documentation/DMA-API.txt
--- a/Documentation/DMA-API.txt~dma_free_coherent-needs-irqs-enabled-sigh
+++ a/Documentation/DMA-API.txt
@@ -68,6 +68,9 @@ size and dma_handle must all be the same
consistent allocate. cpu_addr must be the virtual address returned by
the consistent allocate
+Note that unlike their sibling allocation calls, these routines
+may only be called with IRQs enabled.
+
Part Ib - Using small dma-coherent buffers
------------------------------------------
diff -puN lib/swiotlb.c~dma_free_coherent-needs-irqs-enabled-sigh lib/swiotlb.c
--- a/lib/swiotlb.c~dma_free_coherent-needs-irqs-enabled-sigh
+++ a/lib/swiotlb.c
@@ -497,6 +497,7 @@ void
swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr,
dma_addr_t dma_handle)
{
+ WARN_ON(irqs_disabled());
if (!(vaddr >= (void *)io_tlb_start
&& vaddr < (void *)io_tlb_end))
free_pages((unsigned long) vaddr, get_order(size));
_
Patches currently in -mm which might be from david-b@xxxxxxxxxxx are
origin.patch
rtc-stk17ta8-update-for-sysfs-api-change.patch
rtc-ds1307-typo-fix-found-by-coverity.patch
git-mmc.patch
git-mtd.patch
dma_free_coherent-needs-irqs-enabled-sigh.patch
drivers-pmc-msp71xx-gpio-char-driver.patch
driver-for-the-atmel-on-chip-ssc-on-at32ap-and-at91.patch
clean-up-duplicate-includes-in-drivers-spi.patch
spi-kerneldoc-update.patch
spi-device-setup-gets-better-error-checking.patch
rtc_irq_set_freq-requires-power-of-two-and-associated-kerneldoc.patch
use-menuconfig-objects-rtc.patch
-
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