* [PATCH] MIPS: mm: Move some checks out of 'for' loop in DMA operations
@ 2013-09-25 13:01 Jayachandran C
2013-09-25 13:19 ` Markos Chandras
2013-09-26 10:36 ` Jayachandran C.
0 siblings, 2 replies; 5+ messages in thread
From: Jayachandran C @ 2013-09-25 13:01 UTC (permalink / raw)
To: ralf; +Cc: linux-mips, Jayachandran C
The check cpu_needs_post_dma_flush() in mips_dma_sync_sg_for_cpu() and
the check !plat_device_is_coherent() in mips_dma_sync_sg_for_device()
can be moved outside the for loop.
As a side effect, this also avoids a GCC bug that caused kernel compile
to fail with the error:
arch/mips/mm/dma-default.c: In function 'mips_dma_sync_sg_for_cpu':
arch/mips/mm/dma-default.c:316:1: internal compiler error: in add_insn_before, at emit-rtl.c:3852
This gcc failure is seen in Code Sourcery toolchains [e.g. gcc version
4.7.2 (Sourcery CodeBench Lite 2012.09-99)] after commit "MIPS: Optimize
current_cpu_type() for better code."
---
arch/mips/mm/dma-default.c | 12 ++++--------
1 file changed, 4 insertions(+), 8 deletions(-)
diff --git a/arch/mips/mm/dma-default.c b/arch/mips/mm/dma-default.c
index e45e4b0..2e94185 100644
--- a/arch/mips/mm/dma-default.c
+++ b/arch/mips/mm/dma-default.c
@@ -307,12 +307,10 @@ static void mips_dma_sync_sg_for_cpu(struct device *dev,
{
int i;
- /* Make sure that gcc doesn't leave the empty loop body. */
- for (i = 0; i < nelems; i++, sg++) {
- if (cpu_needs_post_dma_flush(dev))
+ if (cpu_needs_post_dma_flush(dev))
+ for (i = 0; i < nelems; i++, sg++)
__dma_sync(sg_page(sg), sg->offset, sg->length,
direction);
- }
}
static void mips_dma_sync_sg_for_device(struct device *dev,
@@ -320,12 +318,10 @@ static void mips_dma_sync_sg_for_device(struct device *dev,
{
int i;
- /* Make sure that gcc doesn't leave the empty loop body. */
- for (i = 0; i < nelems; i++, sg++) {
- if (!plat_device_is_coherent(dev))
+ if (!plat_device_is_coherent(dev))
+ for (i = 0; i < nelems; i++, sg++)
__dma_sync(sg_page(sg), sg->offset, sg->length,
direction);
- }
}
int mips_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
--
1.7.9.5
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH] MIPS: mm: Move some checks out of 'for' loop in DMA operations
@ 2013-09-25 13:19 ` Markos Chandras
0 siblings, 0 replies; 5+ messages in thread
From: Markos Chandras @ 2013-09-25 13:19 UTC (permalink / raw)
To: Jayachandran C; +Cc: ralf, linux-mips
On 09/25/13 14:01, Jayachandran C wrote:
> The check cpu_needs_post_dma_flush() in mips_dma_sync_sg_for_cpu() and
> the check !plat_device_is_coherent() in mips_dma_sync_sg_for_device()
> can be moved outside the for loop.
>
> As a side effect, this also avoids a GCC bug that caused kernel compile
> to fail with the error:
>
> arch/mips/mm/dma-default.c: In function 'mips_dma_sync_sg_for_cpu':
> arch/mips/mm/dma-default.c:316:1: internal compiler error: in add_insn_before, at emit-rtl.c:3852
>
> This gcc failure is seen in Code Sourcery toolchains [e.g. gcc version
> 4.7.2 (Sourcery CodeBench Lite 2012.09-99)] after commit "MIPS: Optimize
> current_cpu_type() for better code."
> ---
> arch/mips/mm/dma-default.c | 12 ++++--------
> 1 file changed, 4 insertions(+), 8 deletions(-)
>
> diff --git a/arch/mips/mm/dma-default.c b/arch/mips/mm/dma-default.c
> index e45e4b0..2e94185 100644
> --- a/arch/mips/mm/dma-default.c
> +++ b/arch/mips/mm/dma-default.c
> @@ -307,12 +307,10 @@ static void mips_dma_sync_sg_for_cpu(struct device *dev,
> {
> int i;
>
> - /* Make sure that gcc doesn't leave the empty loop body. */
> - for (i = 0; i < nelems; i++, sg++) {
> - if (cpu_needs_post_dma_flush(dev))
> + if (cpu_needs_post_dma_flush(dev))
> + for (i = 0; i < nelems; i++, sg++)
> __dma_sync(sg_page(sg), sg->offset, sg->length,
> direction);
> - }
> }
>
> static void mips_dma_sync_sg_for_device(struct device *dev,
> @@ -320,12 +318,10 @@ static void mips_dma_sync_sg_for_device(struct device *dev,
> {
> int i;
>
> - /* Make sure that gcc doesn't leave the empty loop body. */
> - for (i = 0; i < nelems; i++, sg++) {
> - if (!plat_device_is_coherent(dev))
> + if (!plat_device_is_coherent(dev))
> + for (i = 0; i < nelems; i++, sg++)
> __dma_sync(sg_page(sg), sg->offset, sg->length,
> direction);
> - }
> }
>
> int mips_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
>
Hi,
The patch looks good to me and it fixes the gcc problem indeed (the bug
is also present in gcc-4.7.3 from the 2013.05 release)
Reviewed-by/Tested-by: Markos Chandras <markos.chandras@imgtec.com>
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] MIPS: mm: Move some checks out of 'for' loop in DMA operations
@ 2013-09-25 13:19 ` Markos Chandras
0 siblings, 0 replies; 5+ messages in thread
From: Markos Chandras @ 2013-09-25 13:19 UTC (permalink / raw)
To: Jayachandran C; +Cc: ralf, linux-mips
On 09/25/13 14:01, Jayachandran C wrote:
> The check cpu_needs_post_dma_flush() in mips_dma_sync_sg_for_cpu() and
> the check !plat_device_is_coherent() in mips_dma_sync_sg_for_device()
> can be moved outside the for loop.
>
> As a side effect, this also avoids a GCC bug that caused kernel compile
> to fail with the error:
>
> arch/mips/mm/dma-default.c: In function 'mips_dma_sync_sg_for_cpu':
> arch/mips/mm/dma-default.c:316:1: internal compiler error: in add_insn_before, at emit-rtl.c:3852
>
> This gcc failure is seen in Code Sourcery toolchains [e.g. gcc version
> 4.7.2 (Sourcery CodeBench Lite 2012.09-99)] after commit "MIPS: Optimize
> current_cpu_type() for better code."
> ---
> arch/mips/mm/dma-default.c | 12 ++++--------
> 1 file changed, 4 insertions(+), 8 deletions(-)
>
> diff --git a/arch/mips/mm/dma-default.c b/arch/mips/mm/dma-default.c
> index e45e4b0..2e94185 100644
> --- a/arch/mips/mm/dma-default.c
> +++ b/arch/mips/mm/dma-default.c
> @@ -307,12 +307,10 @@ static void mips_dma_sync_sg_for_cpu(struct device *dev,
> {
> int i;
>
> - /* Make sure that gcc doesn't leave the empty loop body. */
> - for (i = 0; i < nelems; i++, sg++) {
> - if (cpu_needs_post_dma_flush(dev))
> + if (cpu_needs_post_dma_flush(dev))
> + for (i = 0; i < nelems; i++, sg++)
> __dma_sync(sg_page(sg), sg->offset, sg->length,
> direction);
> - }
> }
>
> static void mips_dma_sync_sg_for_device(struct device *dev,
> @@ -320,12 +318,10 @@ static void mips_dma_sync_sg_for_device(struct device *dev,
> {
> int i;
>
> - /* Make sure that gcc doesn't leave the empty loop body. */
> - for (i = 0; i < nelems; i++, sg++) {
> - if (!plat_device_is_coherent(dev))
> + if (!plat_device_is_coherent(dev))
> + for (i = 0; i < nelems; i++, sg++)
> __dma_sync(sg_page(sg), sg->offset, sg->length,
> direction);
> - }
> }
>
> int mips_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
>
Hi,
The patch looks good to me and it fixes the gcc problem indeed (the bug
is also present in gcc-4.7.3 from the 2013.05 release)
Reviewed-by/Tested-by: Markos Chandras <markos.chandras@imgtec.com>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] MIPS: mm: Move some checks out of 'for' loop in DMA operations
2013-09-25 13:01 [PATCH] MIPS: mm: Move some checks out of 'for' loop in DMA operations Jayachandran C
2013-09-25 13:19 ` Markos Chandras
@ 2013-09-26 10:36 ` Jayachandran C.
2013-09-26 14:15 ` Ralf Baechle
1 sibling, 1 reply; 5+ messages in thread
From: Jayachandran C. @ 2013-09-26 10:36 UTC (permalink / raw)
To: ralf; +Cc: linux-mips
On Wed, Sep 25, 2013 at 06:31:05PM +0530, Jayachandran C wrote:
The patch was missing the required Signed-off-by, added below.
> The check cpu_needs_post_dma_flush() in mips_dma_sync_sg_for_cpu() and
> the check !plat_device_is_coherent() in mips_dma_sync_sg_for_device()
> can be moved outside the for loop.
>
> As a side effect, this also avoids a GCC bug that caused kernel compile
> to fail with the error:
>
> arch/mips/mm/dma-default.c: In function 'mips_dma_sync_sg_for_cpu':
> arch/mips/mm/dma-default.c:316:1: internal compiler error: in add_insn_before, at emit-rtl.c:3852
>
> This gcc failure is seen in Code Sourcery toolchains [e.g. gcc version
> 4.7.2 (Sourcery CodeBench Lite 2012.09-99)] after commit "MIPS: Optimize
> current_cpu_type() for better code."
Signed-off-by: Jayachandran C <jchandra@broadcom.com>
> ---
> arch/mips/mm/dma-default.c | 12 ++++--------
> 1 file changed, 4 insertions(+), 8 deletions(-)
>
> diff --git a/arch/mips/mm/dma-default.c b/arch/mips/mm/dma-default.c
> index e45e4b0..2e94185 100644
> --- a/arch/mips/mm/dma-default.c
> +++ b/arch/mips/mm/dma-default.c
> @@ -307,12 +307,10 @@ static void mips_dma_sync_sg_for_cpu(struct device *dev,
> {
> int i;
>
> - /* Make sure that gcc doesn't leave the empty loop body. */
> - for (i = 0; i < nelems; i++, sg++) {
> - if (cpu_needs_post_dma_flush(dev))
> + if (cpu_needs_post_dma_flush(dev))
> + for (i = 0; i < nelems; i++, sg++)
> __dma_sync(sg_page(sg), sg->offset, sg->length,
> direction);
> - }
> }
>
> static void mips_dma_sync_sg_for_device(struct device *dev,
> @@ -320,12 +318,10 @@ static void mips_dma_sync_sg_for_device(struct device *dev,
> {
> int i;
>
> - /* Make sure that gcc doesn't leave the empty loop body. */
> - for (i = 0; i < nelems; i++, sg++) {
> - if (!plat_device_is_coherent(dev))
> + if (!plat_device_is_coherent(dev))
> + for (i = 0; i < nelems; i++, sg++)
> __dma_sync(sg_page(sg), sg->offset, sg->length,
> direction);
> - }
> }
>
> int mips_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
JC.
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] MIPS: mm: Move some checks out of 'for' loop in DMA operations
2013-09-26 10:36 ` Jayachandran C.
@ 2013-09-26 14:15 ` Ralf Baechle
0 siblings, 0 replies; 5+ messages in thread
From: Ralf Baechle @ 2013-09-26 14:15 UTC (permalink / raw)
To: Jayachandran C.; +Cc: linux-mips
On Thu, Sep 26, 2013 at 04:06:52PM +0530, Jayachandran C. wrote:
> The patch was missing the required Signed-off-by, added below.
Thanks, the patch is now in the tree.
(Further sifting through patches is currently being hampered by X crashing
ever faster so I'm back to text console for now ...)
Ralf
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2013-09-26 14:16 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
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2013-09-25 13:01 [PATCH] MIPS: mm: Move some checks out of 'for' loop in DMA operations Jayachandran C
2013-09-25 13:19 ` Markos Chandras
2013-09-25 13:19 ` Markos Chandras
2013-09-26 10:36 ` Jayachandran C.
2013-09-26 14:15 ` Ralf Baechle
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