[PATCH 1/2] bus: mhi: core: Fix parsing of mhi_flags

[PATCH 1/2] bus: mhi: core: Fix parsing of mhi_flags

[Manivannan Sadhasivam]

With the current parsing of mhi_flags, the following statement always
return false:

eob = !!(flags & MHI_EOB);

This is due to the fact that 'enum mhi_flags' starts with index 0 and we
are using direct AND operation to extract each bit. Fix this by using
BIT() macro to extract each bit and make the mhi_flags index start from 1.

Fixes: 189ff97cca53 ("bus: mhi: core: Add support for data transfer")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
---
 drivers/bus/mhi/core/main.c | 6 +++---
 include/linux/mhi.h         | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
index eb4256b81406..4165a853c189 100644
--- a/drivers/bus/mhi/core/main.c
+++ b/drivers/bus/mhi/core/main.c
@@ -1090,9 +1090,9 @@ int mhi_gen_tre(struct mhi_controller *mhi_cntrl, struct mhi_chan *mhi_chan,
 	if (ret)
 		return ret;
 
-	eob = !!(flags & MHI_EOB);
-	eot = !!(flags & MHI_EOT);
-	chain = !!(flags & MHI_CHAIN);
+	eob = !!(flags & BIT(0));
+	eot = !!(flags & BIT(1));
+	chain = !!(flags & BIT(2));
 	bei = !!(mhi_chan->intmod);
 
 	mhi_tre = tre_ring->wp;
diff --git a/include/linux/mhi.h b/include/linux/mhi.h
index ad1996001965..22185fecbbf2 100644
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -53,7 +53,7 @@ enum mhi_callback {
  * @MHI_CHAIN: Linked transfer
  */
 enum mhi_flags {
-	MHI_EOB,
+	MHI_EOB = 1,
 	MHI_EOT,
 	MHI_CHAIN,
 };
-- 
2.17.1

[PATCH 2/2] bus: mhi: core: Fix double lock of 'mhi_chan->lock'

[Manivannan Sadhasivam]

mhi_queue_buf() will grab the 'mhi_chan->lock' for doing the doorbell
access. Hence the lock needs to be dropped before the call.

Fixes: 189ff97cca53 ("bus: mhi: core: Add support for data transfer")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
---
 drivers/bus/mhi/core/main.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
index 4165a853c189..ed995137c3a0 100644
--- a/drivers/bus/mhi/core/main.c
+++ b/drivers/bus/mhi/core/main.c
@@ -538,6 +538,11 @@ static int parse_xfer_event(struct mhi_controller *mhi_cntrl,
 			 * from dropping the packet
 			 */
 			if (mhi_chan->pre_alloc) {
+				/*
+				 * mhi_queue_buf() will grab the mhi_chan->lock
+				 * so let's drop it here and grab it later
+				 */
+				read_unlock_bh(&mhi_chan->lock);
 				if (mhi_queue_buf(mhi_chan->mhi_dev,
 						  mhi_chan->dir,
 						  buf_info->cb_buf,
@@ -547,6 +552,7 @@ static int parse_xfer_event(struct mhi_controller *mhi_cntrl,
 						mhi_chan->chan);
 					kfree(buf_info->cb_buf);
 				}
+				read_lock_bh(&mhi_chan->lock);
 			}
 		}
 		break;
-- 
2.17.1

Re: [PATCH 1/2] bus: mhi: core: Fix parsing of mhi_flags

[Hemant Kumar]

Hi Mani,

On 4/13/20 5:07 AM, Manivannan Sadhasivam wrote:
> With the current parsing of mhi_flags, the following statement always
> return false:
>
> eob = !!(flags & MHI_EOB);
>
> This is due to the fact that 'enum mhi_flags' starts with index 0 and we
> are using direct AND operation to extract each bit. Fix this by using
> BIT() macro to extract each bit and make the mhi_flags index start from 1.
>
> Fixes: 189ff97cca53 ("bus: mhi: core: Add support for data transfer")
> Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> ---
>   drivers/bus/mhi/core/main.c | 6 +++---
>   include/linux/mhi.h         | 2 +-
>   2 files changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
> index eb4256b81406..4165a853c189 100644
> --- a/drivers/bus/mhi/core/main.c
> +++ b/drivers/bus/mhi/core/main.c
> @@ -1090,9 +1090,9 @@ int mhi_gen_tre(struct mhi_controller *mhi_cntrl, struct mhi_chan *mhi_chan,
>   	if (ret)
>   		return ret;
>   
> -	eob = !!(flags & MHI_EOB);
> -	eot = !!(flags & MHI_EOT);
> -	chain = !!(flags & MHI_CHAIN);
> +	eob = !!(flags & BIT(0));
> +	eot = !!(flags & BIT(1));
> +	chain = !!(flags & BIT(2));

How about setting enums  with BIT macro and still use same enums above. 
If flags is having MHI _CHAIN (enum value 3) but comparing with BIT(2) 
(value 4) will not work.

>   	bei = !!(mhi_chan->intmod);
>   
>   	mhi_tre = tre_ring->wp;
> diff --git a/include/linux/mhi.h b/include/linux/mhi.h
> index ad1996001965..22185fecbbf2 100644
> --- a/include/linux/mhi.h
> +++ b/include/linux/mhi.h
> @@ -53,7 +53,7 @@ enum mhi_callback {
>    * @MHI_CHAIN: Linked transfer
>    */
>   enum mhi_flags {
> -	MHI_EOB,
> +	MHI_EOB = 1,
>   	MHI_EOT,
>   	MHI_CHAIN,
>   };

enum mhi_flags {

     MHI_EOB = BIT(0),

     MHI_EOT = BIT(1),

     MHI_CHAIN = BIT(2),

}

-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

Re: [PATCH 1/2] bus: mhi: core: Fix parsing of mhi_flags

[Manivannan Sadhasivam]

On Thu, Apr 16, 2020 at 12:01:30PM -0700, Hemant Kumar wrote:
> Hi Mani,
> 
> On 4/13/20 5:07 AM, Manivannan Sadhasivam wrote:
> > With the current parsing of mhi_flags, the following statement always
> > return false:
> > 
> > eob = !!(flags & MHI_EOB);
> > 
> > This is due to the fact that 'enum mhi_flags' starts with index 0 and we
> > are using direct AND operation to extract each bit. Fix this by using
> > BIT() macro to extract each bit and make the mhi_flags index start from 1.
> > 
> > Fixes: 189ff97cca53 ("bus: mhi: core: Add support for data transfer")
> > Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> > Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> > ---
> >   drivers/bus/mhi/core/main.c | 6 +++---
> >   include/linux/mhi.h         | 2 +-
> >   2 files changed, 4 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
> > index eb4256b81406..4165a853c189 100644
> > --- a/drivers/bus/mhi/core/main.c
> > +++ b/drivers/bus/mhi/core/main.c
> > @@ -1090,9 +1090,9 @@ int mhi_gen_tre(struct mhi_controller *mhi_cntrl, struct mhi_chan *mhi_chan,
> >   	if (ret)
> >   		return ret;
> > -	eob = !!(flags & MHI_EOB);
> > -	eot = !!(flags & MHI_EOT);
> > -	chain = !!(flags & MHI_CHAIN);
> > +	eob = !!(flags & BIT(0));
> > +	eot = !!(flags & BIT(1));
> > +	chain = !!(flags & BIT(2));
> 
> How about setting enums  with BIT macro and still use same enums above. If
> flags is having MHI _CHAIN (enum value 3) but comparing with BIT(2) (value
> 4) will not work.
> 

Doh, you are right. Will fix it!

Thanks,
Mani

> >   	bei = !!(mhi_chan->intmod);
> >   	mhi_tre = tre_ring->wp;
> > diff --git a/include/linux/mhi.h b/include/linux/mhi.h
> > index ad1996001965..22185fecbbf2 100644
> > --- a/include/linux/mhi.h
> > +++ b/include/linux/mhi.h
> > @@ -53,7 +53,7 @@ enum mhi_callback {
> >    * @MHI_CHAIN: Linked transfer
> >    */
> >   enum mhi_flags {
> > -	MHI_EOB,
> > +	MHI_EOB = 1,
> >   	MHI_EOT,
> >   	MHI_CHAIN,
> >   };
> 
> enum mhi_flags {
> 
>     MHI_EOB = BIT(0),
> 
>     MHI_EOT = BIT(1),
> 
>     MHI_CHAIN = BIT(2),
> 
> }
> 
> -- 
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project