From: Qiang Liu <[email protected]>
- use spin_lock_bh() is the right way to use async_tx api,
dma_run_dependencies() should not be protected by spin_lock_irqsave();
- use spin_lock_bh to instead of spin_lock_irqsave for improving performance,
There is not any place to access descriptor queues in fsl-dma ISR except its
tasklet, spin_lock_bh() is more proper here. Interrupts will be turned off and
context will be save in irqsave, there is needless to use irqsave..
Cc: Dan Williams <[email protected]>
Cc: Vinod Koul <[email protected]>
Cc: Li Yang <[email protected]>
Cc: Timur Tabi <[email protected]>
Signed-off-by: Qiang Liu <[email protected]>
---
drivers/dma/fsldma.c | 30 ++++++++++++------------------
1 files changed, 12 insertions(+), 18 deletions(-)
diff --git a/drivers/dma/fsldma.c b/drivers/dma/fsldma.c
index bb883c0..e3814aa 100644
--- a/drivers/dma/fsldma.c
+++ b/drivers/dma/fsldma.c
@@ -645,10 +645,9 @@ static dma_cookie_t fsl_dma_tx_submit(struct dma_async_tx_descriptor *tx)
struct fsldma_chan *chan = to_fsl_chan(tx->chan);
struct fsl_desc_sw *desc = tx_to_fsl_desc(tx);
struct fsl_desc_sw *child;
- unsigned long flags;
dma_cookie_t cookie;
- spin_lock_irqsave(&chan->desc_lock, flags);
+ spin_lock_bh(&chan->desc_lock);
/*
* assign cookies to all of the software descriptors
@@ -661,7 +660,7 @@ static dma_cookie_t fsl_dma_tx_submit(struct dma_async_tx_descriptor *tx)
/* put this transaction onto the tail of the pending queue */
append_ld_queue(chan, desc);
- spin_unlock_irqrestore(&chan->desc_lock, flags);
+ spin_unlock_bh(&chan->desc_lock);
return cookie;
}
@@ -770,15 +769,14 @@ static void fsldma_free_desc_list_reverse(struct fsldma_chan *chan,
static void fsl_dma_free_chan_resources(struct dma_chan *dchan)
{
struct fsldma_chan *chan = to_fsl_chan(dchan);
- unsigned long flags;
chan_dbg(chan, "free all channel resources\n");
- spin_lock_irqsave(&chan->desc_lock, flags);
+ spin_lock_bh(&chan->desc_lock);
fsldma_cleanup_descriptor(chan);
fsldma_free_desc_list(chan, &chan->ld_pending);
fsldma_free_desc_list(chan, &chan->ld_running);
fsldma_free_desc_list(chan, &chan->ld_completed);
- spin_unlock_irqrestore(&chan->desc_lock, flags);
+ spin_unlock_bh(&chan->desc_lock);
dma_pool_destroy(chan->desc_pool);
chan->desc_pool = NULL;
@@ -997,7 +995,6 @@ static int fsl_dma_device_control(struct dma_chan *dchan,
{
struct dma_slave_config *config;
struct fsldma_chan *chan;
- unsigned long flags;
int size;
if (!dchan)
@@ -1007,7 +1004,7 @@ static int fsl_dma_device_control(struct dma_chan *dchan,
switch (cmd) {
case DMA_TERMINATE_ALL:
- spin_lock_irqsave(&chan->desc_lock, flags);
+ spin_lock_bh(&chan->desc_lock);
/* Halt the DMA engine */
dma_halt(chan);
@@ -1017,7 +1014,7 @@ static int fsl_dma_device_control(struct dma_chan *dchan,
fsldma_free_desc_list(chan, &chan->ld_running);
chan->idle = true;
- spin_unlock_irqrestore(&chan->desc_lock, flags);
+ spin_unlock_bh(&chan->desc_lock);
return 0;
case DMA_SLAVE_CONFIG:
@@ -1059,11 +1056,10 @@ static int fsl_dma_device_control(struct dma_chan *dchan,
static void fsl_dma_memcpy_issue_pending(struct dma_chan *dchan)
{
struct fsldma_chan *chan = to_fsl_chan(dchan);
- unsigned long flags;
- spin_lock_irqsave(&chan->desc_lock, flags);
+ spin_lock_bh(&chan->desc_lock);
fsl_chan_xfer_ld_queue(chan);
- spin_unlock_irqrestore(&chan->desc_lock, flags);
+ spin_unlock_bh(&chan->desc_lock);
}
/**
@@ -1076,15 +1072,14 @@ static enum dma_status fsl_tx_status(struct dma_chan *dchan,
{
struct fsldma_chan *chan = to_fsl_chan(dchan);
enum dma_status ret;
- unsigned long flags;
ret = dma_cookie_status(dchan, cookie, txstate);
if (ret == DMA_SUCCESS)
return ret;
- spin_lock_irqsave(&chan->desc_lock, flags);
+ spin_lock_bh(&chan->desc_lock);
fsldma_cleanup_descriptor(chan);
- spin_unlock_irqrestore(&chan->desc_lock, flags);
+ spin_unlock_bh(&chan->desc_lock);
return dma_cookie_status(dchan, cookie, txstate);
}
@@ -1163,11 +1158,10 @@ static irqreturn_t fsldma_chan_irq(int irq, void *data)
static void dma_do_tasklet(unsigned long data)
{
struct fsldma_chan *chan = (struct fsldma_chan *)data;
- unsigned long flags;
chan_dbg(chan, "tasklet entry\n");
- spin_lock_irqsave(&chan->desc_lock, flags);
+ spin_lock_bh(&chan->desc_lock);
/* the hardware is now idle and ready for more */
chan->idle = true;
@@ -1175,7 +1169,7 @@ static void dma_do_tasklet(unsigned long data)
/* Run all cleanup for this descriptor */
fsldma_cleanup_descriptor(chan);
- spin_unlock_irqrestore(&chan->desc_lock, flags);
+ spin_unlock_bh(&chan->desc_lock);
chan_dbg(chan, "tasklet exit\n");
}
--
1.7.5.1
On Wed, Aug 01, 2012 at 04:50:09PM +0800, [email protected] wrote:
> From: Qiang Liu <[email protected]>
>
> - use spin_lock_bh() is the right way to use async_tx api,
> dma_run_dependencies() should not be protected by spin_lock_irqsave();
> - use spin_lock_bh to instead of spin_lock_irqsave for improving performance,
> There is not any place to access descriptor queues in fsl-dma ISR except its
> tasklet, spin_lock_bh() is more proper here. Interrupts will be turned off and
> context will be save in irqsave, there is needless to use irqsave..
>
This description is not very clear English. I understand it is not your
native language. Let me try to help.
"""
The use of spin_lock_irqsave() is a stronger locking mechanism than is
required throughout the driver. The minimum locking required should be
used instead.
Change all instances of spin_lock_irqsave() to spin_lock_bh(). All
manipulation of protected fields is done using tasklet context or
weaker, which makes spin_lock_bh() the correct choice.
"""
Other than that,
Acked-by: Ira W. Snyder <[email protected]>
> Cc: Dan Williams <[email protected]>
> Cc: Vinod Koul <[email protected]>
> Cc: Li Yang <[email protected]>
> Cc: Timur Tabi <[email protected]>
> Signed-off-by: Qiang Liu <[email protected]>
> ---
> drivers/dma/fsldma.c | 30 ++++++++++++------------------
> 1 files changed, 12 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/dma/fsldma.c b/drivers/dma/fsldma.c
> index bb883c0..e3814aa 100644
> --- a/drivers/dma/fsldma.c
> +++ b/drivers/dma/fsldma.c
> @@ -645,10 +645,9 @@ static dma_cookie_t fsl_dma_tx_submit(struct dma_async_tx_descriptor *tx)
> struct fsldma_chan *chan = to_fsl_chan(tx->chan);
> struct fsl_desc_sw *desc = tx_to_fsl_desc(tx);
> struct fsl_desc_sw *child;
> - unsigned long flags;
> dma_cookie_t cookie;
>
> - spin_lock_irqsave(&chan->desc_lock, flags);
> + spin_lock_bh(&chan->desc_lock);
>
> /*
> * assign cookies to all of the software descriptors
> @@ -661,7 +660,7 @@ static dma_cookie_t fsl_dma_tx_submit(struct dma_async_tx_descriptor *tx)
> /* put this transaction onto the tail of the pending queue */
> append_ld_queue(chan, desc);
>
> - spin_unlock_irqrestore(&chan->desc_lock, flags);
> + spin_unlock_bh(&chan->desc_lock);
>
> return cookie;
> }
> @@ -770,15 +769,14 @@ static void fsldma_free_desc_list_reverse(struct fsldma_chan *chan,
> static void fsl_dma_free_chan_resources(struct dma_chan *dchan)
> {
> struct fsldma_chan *chan = to_fsl_chan(dchan);
> - unsigned long flags;
>
> chan_dbg(chan, "free all channel resources\n");
> - spin_lock_irqsave(&chan->desc_lock, flags);
> + spin_lock_bh(&chan->desc_lock);
> fsldma_cleanup_descriptor(chan);
> fsldma_free_desc_list(chan, &chan->ld_pending);
> fsldma_free_desc_list(chan, &chan->ld_running);
> fsldma_free_desc_list(chan, &chan->ld_completed);
> - spin_unlock_irqrestore(&chan->desc_lock, flags);
> + spin_unlock_bh(&chan->desc_lock);
>
> dma_pool_destroy(chan->desc_pool);
> chan->desc_pool = NULL;
> @@ -997,7 +995,6 @@ static int fsl_dma_device_control(struct dma_chan *dchan,
> {
> struct dma_slave_config *config;
> struct fsldma_chan *chan;
> - unsigned long flags;
> int size;
>
> if (!dchan)
> @@ -1007,7 +1004,7 @@ static int fsl_dma_device_control(struct dma_chan *dchan,
>
> switch (cmd) {
> case DMA_TERMINATE_ALL:
> - spin_lock_irqsave(&chan->desc_lock, flags);
> + spin_lock_bh(&chan->desc_lock);
>
> /* Halt the DMA engine */
> dma_halt(chan);
> @@ -1017,7 +1014,7 @@ static int fsl_dma_device_control(struct dma_chan *dchan,
> fsldma_free_desc_list(chan, &chan->ld_running);
> chan->idle = true;
>
> - spin_unlock_irqrestore(&chan->desc_lock, flags);
> + spin_unlock_bh(&chan->desc_lock);
> return 0;
>
> case DMA_SLAVE_CONFIG:
> @@ -1059,11 +1056,10 @@ static int fsl_dma_device_control(struct dma_chan *dchan,
> static void fsl_dma_memcpy_issue_pending(struct dma_chan *dchan)
> {
> struct fsldma_chan *chan = to_fsl_chan(dchan);
> - unsigned long flags;
>
> - spin_lock_irqsave(&chan->desc_lock, flags);
> + spin_lock_bh(&chan->desc_lock);
> fsl_chan_xfer_ld_queue(chan);
> - spin_unlock_irqrestore(&chan->desc_lock, flags);
> + spin_unlock_bh(&chan->desc_lock);
> }
>
> /**
> @@ -1076,15 +1072,14 @@ static enum dma_status fsl_tx_status(struct dma_chan *dchan,
> {
> struct fsldma_chan *chan = to_fsl_chan(dchan);
> enum dma_status ret;
> - unsigned long flags;
>
> ret = dma_cookie_status(dchan, cookie, txstate);
> if (ret == DMA_SUCCESS)
> return ret;
>
> - spin_lock_irqsave(&chan->desc_lock, flags);
> + spin_lock_bh(&chan->desc_lock);
> fsldma_cleanup_descriptor(chan);
> - spin_unlock_irqrestore(&chan->desc_lock, flags);
> + spin_unlock_bh(&chan->desc_lock);
>
> return dma_cookie_status(dchan, cookie, txstate);
> }
> @@ -1163,11 +1158,10 @@ static irqreturn_t fsldma_chan_irq(int irq, void *data)
> static void dma_do_tasklet(unsigned long data)
> {
> struct fsldma_chan *chan = (struct fsldma_chan *)data;
> - unsigned long flags;
>
> chan_dbg(chan, "tasklet entry\n");
>
> - spin_lock_irqsave(&chan->desc_lock, flags);
> + spin_lock_bh(&chan->desc_lock);
>
> /* the hardware is now idle and ready for more */
> chan->idle = true;
> @@ -1175,7 +1169,7 @@ static void dma_do_tasklet(unsigned long data)
> /* Run all cleanup for this descriptor */
> fsldma_cleanup_descriptor(chan);
>
> - spin_unlock_irqrestore(&chan->desc_lock, flags);
> + spin_unlock_bh(&chan->desc_lock);
>
> chan_dbg(chan, "tasklet exit\n");
> }
> --
> 1.7.5.1
>
>
> _______________________________________________
> Linuxppc-dev mailing list
> [email protected]
> https://lists.ozlabs.org/listinfo/linuxppc-dev
> -----Original Message-----
> From: Ira W. Snyder [mailto:[email protected]]
> Sent: Thursday, August 02, 2012 1:31 AM
> To: Liu Qiang-B32616
> Cc: [email protected]; [email protected]; linux-
> [email protected]; [email protected]; Vinod Koul; Tabi Timur-
> B04825; [email protected]; Dan Williams; [email protected]
> Subject: Re: [PATCH v5 5/6] fsl-dma: use spin_lock_bh to instead of
> spin_lock_irqsave
>
> On Wed, Aug 01, 2012 at 04:50:09PM +0800, [email protected] wrote:
> > From: Qiang Liu <[email protected]>
> >
> > - use spin_lock_bh() is the right way to use async_tx api,
> > dma_run_dependencies() should not be protected by spin_lock_irqsave();
> > - use spin_lock_bh to instead of spin_lock_irqsave for improving
> > performance, There is not any place to access descriptor queues in
> > fsl-dma ISR except its tasklet, spin_lock_bh() is more proper here.
> > Interrupts will be turned off and context will be save in irqsave,
> there is needless to use irqsave..
> >
>
> This description is not very clear English. I understand it is not your
> native language. Let me try to help.
>
> """
> The use of spin_lock_irqsave() is a stronger locking mechanism than is
> required throughout the driver. The minimum locking required should be
> used instead.
>
> Change all instances of spin_lock_irqsave() to spin_lock_bh(). All
> manipulation of protected fields is done using tasklet context or weaker,
> which makes spin_lock_bh() the correct choice.
> """
I will modify the description in v6, please check later.
>
> Other than that,
> Acked-by: Ira W. Snyder <[email protected]>
Thanks.
>
> > Cc: Dan Williams <[email protected]>
> > Cc: Vinod Koul <[email protected]>
> > Cc: Li Yang <[email protected]>
> > Cc: Timur Tabi <[email protected]>
> > Signed-off-by: Qiang Liu <[email protected]>
> > ---
> > drivers/dma/fsldma.c | 30 ++++++++++++------------------
> > 1 files changed, 12 insertions(+), 18 deletions(-)
> >
> > diff --git a/drivers/dma/fsldma.c b/drivers/dma/fsldma.c index
> > bb883c0..e3814aa 100644
> > --- a/drivers/dma/fsldma.c
> > +++ b/drivers/dma/fsldma.c
> > @@ -645,10 +645,9 @@ static dma_cookie_t fsl_dma_tx_submit(struct
> dma_async_tx_descriptor *tx)
> > struct fsldma_chan *chan = to_fsl_chan(tx->chan);
> > struct fsl_desc_sw *desc = tx_to_fsl_desc(tx);
> > struct fsl_desc_sw *child;
> > - unsigned long flags;
> > dma_cookie_t cookie;
> >
> > - spin_lock_irqsave(&chan->desc_lock, flags);
> > + spin_lock_bh(&chan->desc_lock);
> >
> > /*
> > * assign cookies to all of the software descriptors @@ -661,7
> > +660,7 @@ static dma_cookie_t fsl_dma_tx_submit(struct
> dma_async_tx_descriptor *tx)
> > /* put this transaction onto the tail of the pending queue */
> > append_ld_queue(chan, desc);
> >
> > - spin_unlock_irqrestore(&chan->desc_lock, flags);
> > + spin_unlock_bh(&chan->desc_lock);
> >
> > return cookie;
> > }
> > @@ -770,15 +769,14 @@ static void fsldma_free_desc_list_reverse(struct
> > fsldma_chan *chan, static void fsl_dma_free_chan_resources(struct
> > dma_chan *dchan) {
> > struct fsldma_chan *chan = to_fsl_chan(dchan);
> > - unsigned long flags;
> >
> > chan_dbg(chan, "free all channel resources\n");
> > - spin_lock_irqsave(&chan->desc_lock, flags);
> > + spin_lock_bh(&chan->desc_lock);
> > fsldma_cleanup_descriptor(chan);
> > fsldma_free_desc_list(chan, &chan->ld_pending);
> > fsldma_free_desc_list(chan, &chan->ld_running);
> > fsldma_free_desc_list(chan, &chan->ld_completed);
> > - spin_unlock_irqrestore(&chan->desc_lock, flags);
> > + spin_unlock_bh(&chan->desc_lock);
> >
> > dma_pool_destroy(chan->desc_pool);
> > chan->desc_pool = NULL;
> > @@ -997,7 +995,6 @@ static int fsl_dma_device_control(struct dma_chan
> > *dchan, {
> > struct dma_slave_config *config;
> > struct fsldma_chan *chan;
> > - unsigned long flags;
> > int size;
> >
> > if (!dchan)
> > @@ -1007,7 +1004,7 @@ static int fsl_dma_device_control(struct
> > dma_chan *dchan,
> >
> > switch (cmd) {
> > case DMA_TERMINATE_ALL:
> > - spin_lock_irqsave(&chan->desc_lock, flags);
> > + spin_lock_bh(&chan->desc_lock);
> >
> > /* Halt the DMA engine */
> > dma_halt(chan);
> > @@ -1017,7 +1014,7 @@ static int fsl_dma_device_control(struct dma_chan
> *dchan,
> > fsldma_free_desc_list(chan, &chan->ld_running);
> > chan->idle = true;
> >
> > - spin_unlock_irqrestore(&chan->desc_lock, flags);
> > + spin_unlock_bh(&chan->desc_lock);
> > return 0;
> >
> > case DMA_SLAVE_CONFIG:
> > @@ -1059,11 +1056,10 @@ static int fsl_dma_device_control(struct
> > dma_chan *dchan, static void fsl_dma_memcpy_issue_pending(struct
> > dma_chan *dchan) {
> > struct fsldma_chan *chan = to_fsl_chan(dchan);
> > - unsigned long flags;
> >
> > - spin_lock_irqsave(&chan->desc_lock, flags);
> > + spin_lock_bh(&chan->desc_lock);
> > fsl_chan_xfer_ld_queue(chan);
> > - spin_unlock_irqrestore(&chan->desc_lock, flags);
> > + spin_unlock_bh(&chan->desc_lock);
> > }
> >
> > /**
> > @@ -1076,15 +1072,14 @@ static enum dma_status fsl_tx_status(struct
> > dma_chan *dchan, {
> > struct fsldma_chan *chan = to_fsl_chan(dchan);
> > enum dma_status ret;
> > - unsigned long flags;
> >
> > ret = dma_cookie_status(dchan, cookie, txstate);
> > if (ret == DMA_SUCCESS)
> > return ret;
> >
> > - spin_lock_irqsave(&chan->desc_lock, flags);
> > + spin_lock_bh(&chan->desc_lock);
> > fsldma_cleanup_descriptor(chan);
> > - spin_unlock_irqrestore(&chan->desc_lock, flags);
> > + spin_unlock_bh(&chan->desc_lock);
> >
> > return dma_cookie_status(dchan, cookie, txstate); } @@ -1163,11
> > +1158,10 @@ static irqreturn_t fsldma_chan_irq(int irq, void *data)
> > static void dma_do_tasklet(unsigned long data) {
> > struct fsldma_chan *chan = (struct fsldma_chan *)data;
> > - unsigned long flags;
> >
> > chan_dbg(chan, "tasklet entry\n");
> >
> > - spin_lock_irqsave(&chan->desc_lock, flags);
> > + spin_lock_bh(&chan->desc_lock);
> >
> > /* the hardware is now idle and ready for more */
> > chan->idle = true;
> > @@ -1175,7 +1169,7 @@ static void dma_do_tasklet(unsigned long data)
> > /* Run all cleanup for this descriptor */
> > fsldma_cleanup_descriptor(chan);
> >
> > - spin_unlock_irqrestore(&chan->desc_lock, flags);
> > + spin_unlock_bh(&chan->desc_lock);
> >
> > chan_dbg(chan, "tasklet exit\n");
> > }
> > --
> > 1.7.5.1
> >
> >
> > _______________________________________________
> > Linuxppc-dev mailing list
> > [email protected]
> > https://lists.ozlabs.org/listinfo/linuxppc-dev