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* [PATCH -next] scsi: storvsc: Fix unsigned comparison to zero
@ 2021-12-24 12:02 YueHaibing
  2021-12-26 19:49 ` Michael Kelley (LINUX)
  0 siblings, 1 reply; 3+ messages in thread
From: YueHaibing @ 2021-12-24 12:02 UTC (permalink / raw)
  To: kys, haiyangz, sthemmin, wei.liu, decui, jejb, martin.petersen,
	mikelley, Tianyu.Lan, longli
  Cc: linux-hyperv, linux-scsi, linux-kernel, YueHaibing

The unsigned variable sg_count is being assigned a return value
from the call to scsi_dma_map() that can return -ENOMEM.

Fixes: 743b237c3a7b ("scsi: storvsc: Add Isolation VM support for storvsc driver")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
---
 drivers/scsi/storvsc_drv.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
index ae293600d799..072c752a8c36 100644
--- a/drivers/scsi/storvsc_drv.c
+++ b/drivers/scsi/storvsc_drv.c
@@ -1837,7 +1837,7 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
 		unsigned int hvpg_count = HVPFN_UP(offset_in_hvpg + length);
 		struct scatterlist *sg;
 		unsigned long hvpfn, hvpfns_to_add;
-		int j, i = 0;
+		int sg_cnt, j, i = 0;
 
 		if (hvpg_count > MAX_PAGE_BUFFER_COUNT) {
 
@@ -1851,11 +1851,11 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
 		payload->range.len = length;
 		payload->range.offset = offset_in_hvpg;
 
-		sg_count = scsi_dma_map(scmnd);
-		if (sg_count < 0)
+		sg_cnt = scsi_dma_map(scmnd);
+		if (sg_cnt < 0)
 			return SCSI_MLQUEUE_DEVICE_BUSY;
 
-		for_each_sg(sgl, sg, sg_count, j) {
+		for_each_sg(sgl, sg, sg_cnt, j) {
 			/*
 			 * Init values for the current sgl entry. hvpfns_to_add
 			 * is in units of Hyper-V size pages. Handling the
-- 
2.17.1


^ permalink raw reply related	[flat|nested] 3+ messages in thread
* RE: [PATCH -next] scsi: storvsc: Fix unsigned comparison to zero
  2021-12-24 12:02 [PATCH -next] scsi: storvsc: Fix unsigned comparison to zero YueHaibing
@ 2021-12-26 19:49 ` Michael Kelley (LINUX)
  2021-12-27  4:04   ` YueHaibing
  0 siblings, 1 reply; 3+ messages in thread
From: Michael Kelley (LINUX) @ 2021-12-26 19:49 UTC (permalink / raw)
  To: YueHaibing, KY Srinivasan, Haiyang Zhang, Stephen Hemminger,
	wei.liu, Dexuan Cui, jejb, martin.petersen, Tianyu Lan, Long Li
  Cc: linux-hyperv, linux-scsi, linux-kernel

From: YueHaibing <yuehaibing@huawei.com> Sent: Friday, December 24, 2021 4:02 AM
> 
> The unsigned variable sg_count is being assigned a return value
> from the call to scsi_dma_map() that can return -ENOMEM.
> 
> Fixes: 743b237c3a7b ("scsi: storvsc: Add Isolation VM support for storvsc driver")
> Signed-off-by: YueHaibing <yuehaibing@huawei.com>

Good catch!  But I wonder if a simpler fix is to just remove the "unsigned"
from the declaration of sg_count.  Then we don't need to add the
sg_cnt local variable.  A little less complexity is almost always better. :-)

Michael

> ---
>  drivers/scsi/storvsc_drv.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
> index ae293600d799..072c752a8c36 100644
> --- a/drivers/scsi/storvsc_drv.c
> +++ b/drivers/scsi/storvsc_drv.c
> @@ -1837,7 +1837,7 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
>  		unsigned int hvpg_count = HVPFN_UP(offset_in_hvpg + length);
>  		struct scatterlist *sg;
>  		unsigned long hvpfn, hvpfns_to_add;
> -		int j, i = 0;
> +		int sg_cnt, j, i = 0;
> 
>  		if (hvpg_count > MAX_PAGE_BUFFER_COUNT) {
> 
> @@ -1851,11 +1851,11 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
>  		payload->range.len = length;
>  		payload->range.offset = offset_in_hvpg;
> 
> -		sg_count = scsi_dma_map(scmnd);
> -		if (sg_count < 0)
> +		sg_cnt = scsi_dma_map(scmnd);
> +		if (sg_cnt < 0)
>  			return SCSI_MLQUEUE_DEVICE_BUSY;
> 
> -		for_each_sg(sgl, sg, sg_count, j) {
> +		for_each_sg(sgl, sg, sg_cnt, j) {
>  			/*
>  			 * Init values for the current sgl entry. hvpfns_to_add
>  			 * is in units of Hyper-V size pages. Handling the
> --
> 2.17.1


^ permalink raw reply	[flat|nested] 3+ messages in thread
* Re: [PATCH -next] scsi: storvsc: Fix unsigned comparison to zero
  2021-12-26 19:49 ` Michael Kelley (LINUX)
@ 2021-12-27  4:04   ` YueHaibing
  0 siblings, 0 replies; 3+ messages in thread
From: YueHaibing @ 2021-12-27  4:04 UTC (permalink / raw)
  To: Michael Kelley (LINUX),
	KY Srinivasan, Haiyang Zhang, Stephen Hemminger, wei.liu,
	Dexuan Cui, jejb, martin.petersen, Tianyu Lan, Long Li
  Cc: linux-hyperv, linux-scsi, linux-kernel

On 2021/12/27 3:49, Michael Kelley (LINUX) wrote:
> From: YueHaibing <yuehaibing@huawei.com> Sent: Friday, December 24, 2021 4:02 AM
>>
>> The unsigned variable sg_count is being assigned a return value
>> from the call to scsi_dma_map() that can return -ENOMEM.
>>
>> Fixes: 743b237c3a7b ("scsi: storvsc: Add Isolation VM support for storvsc driver")
>> Signed-off-by: YueHaibing <yuehaibing@huawei.com>
> 
> Good catch!  But I wonder if a simpler fix is to just remove the "unsigned"
> from the declaration of sg_count.  Then we don't need to add the
> sg_cnt local variable.  A little less complexity is almost always better. :-)

Ok， will respine
> 
> Michael
> 
>> ---
>>  drivers/scsi/storvsc_drv.c | 8 ++++----
>>  1 file changed, 4 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
>> index ae293600d799..072c752a8c36 100644
>> --- a/drivers/scsi/storvsc_drv.c
>> +++ b/drivers/scsi/storvsc_drv.c
>> @@ -1837,7 +1837,7 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
>>  		unsigned int hvpg_count = HVPFN_UP(offset_in_hvpg + length);
>>  		struct scatterlist *sg;
>>  		unsigned long hvpfn, hvpfns_to_add;
>> -		int j, i = 0;
>> +		int sg_cnt, j, i = 0;
>>
>>  		if (hvpg_count > MAX_PAGE_BUFFER_COUNT) {
>>
>> @@ -1851,11 +1851,11 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
>>  		payload->range.len = length;
>>  		payload->range.offset = offset_in_hvpg;
>>
>> -		sg_count = scsi_dma_map(scmnd);
>> -		if (sg_count < 0)
>> +		sg_cnt = scsi_dma_map(scmnd);
>> +		if (sg_cnt < 0)
>>  			return SCSI_MLQUEUE_DEVICE_BUSY;
>>
>> -		for_each_sg(sgl, sg, sg_count, j) {
>> +		for_each_sg(sgl, sg, sg_cnt, j) {
>>  			/*
>>  			 * Init values for the current sgl entry. hvpfns_to_add
>>  			 * is in units of Hyper-V size pages. Handling the
>> --
>> 2.17.1
> 
> .
> 

^ permalink raw reply	[flat|nested] 3+ messages in thread
end of thread, other threads:[~2021-12-27  4:04 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2021-12-24 12:02 [PATCH -next] scsi: storvsc: Fix unsigned comparison to zero YueHaibing
2021-12-26 19:49 ` Michael Kelley (LINUX)
2021-12-27  4:04   ` YueHaibing

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