* [PATCH][next] vhost: only return early if ret indicates an error or no iovecs have been processed
@ 2019-02-19 13:57 Colin King
2019-02-19 16:35 ` Michael S. Tsirkin
0 siblings, 1 reply; 3+ messages in thread
From: Colin King @ 2019-02-19 13:57 UTC (permalink / raw)
To: Michael S . Tsirkin, Jason Wang, kvm, virtualization, netdev
Cc: kernel-janitors, linux-kernel
From: Colin Ian King <colin.king@canonical.com>
Currently the loop that calls log_write_hva on each iovec is never
executed because of an incorrect error check on the return from the
call to translate_desc. The check should be checking for a -ve error
return and because it makes no sense to iterate over zero items, the
checks should also check for zero too.
Detected by CoverityScan, CID#1476969 ("Logically dead code")
Fixes: cc5e71075947 ("vhost: log dirty page correctly")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
drivers/vhost/vhost.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 24a129fcdd61..a9a1709a859a 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -1788,7 +1788,7 @@ static int log_used(struct vhost_virtqueue *vq, u64 used_offset, u64 len)
ret = translate_desc(vq, (uintptr_t)vq->used + used_offset,
len, iov, 64, VHOST_ACCESS_WO);
- if (ret)
+ if (ret <= 0)
return ret;
for (i = 0; i < ret; i++) {
--
2.20.1
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH][next] vhost: only return early if ret indicates an error or no iovecs have been processed
2019-02-19 13:57 [PATCH][next] vhost: only return early if ret indicates an error or no iovecs have been processed Colin King
@ 2019-02-19 16:35 ` Michael S. Tsirkin
2019-02-19 16:40 ` Colin Ian King
0 siblings, 1 reply; 3+ messages in thread
From: Michael S. Tsirkin @ 2019-02-19 16:35 UTC (permalink / raw)
To: Colin King
Cc: Jason Wang, kvm, virtualization, netdev, kernel-janitors, linux-kernel
On Tue, Feb 19, 2019 at 01:57:13PM +0000, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
>
> Currently the loop that calls log_write_hva on each iovec is never
> executed because of an incorrect error check on the return from the
> call to translate_desc. The check should be checking for a -ve error
> return and because it makes no sense to iterate over zero items, the
> checks should also check for zero too.
>
> Detected by CoverityScan, CID#1476969 ("Logically dead code")
>
> Fixes: cc5e71075947 ("vhost: log dirty page correctly")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
Jason posted a similar patch recently.
Are you happy with that one?
> ---
> drivers/vhost/vhost.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> index 24a129fcdd61..a9a1709a859a 100644
> --- a/drivers/vhost/vhost.c
> +++ b/drivers/vhost/vhost.c
> @@ -1788,7 +1788,7 @@ static int log_used(struct vhost_virtqueue *vq, u64 used_offset, u64 len)
>
> ret = translate_desc(vq, (uintptr_t)vq->used + used_offset,
> len, iov, 64, VHOST_ACCESS_WO);
> - if (ret)
> + if (ret <= 0)
> return ret;
>
> for (i = 0; i < ret; i++) {
> --
> 2.20.1
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH][next] vhost: only return early if ret indicates an error or no iovecs have been processed
2019-02-19 16:35 ` Michael S. Tsirkin
@ 2019-02-19 16:40 ` Colin Ian King
0 siblings, 0 replies; 3+ messages in thread
From: Colin Ian King @ 2019-02-19 16:40 UTC (permalink / raw)
To: Michael S. Tsirkin
Cc: Jason Wang, kvm, virtualization, netdev, kernel-janitors, linux-kernel
On 19/02/2019 16:35, Michael S. Tsirkin wrote:
> On Tue, Feb 19, 2019 at 01:57:13PM +0000, Colin King wrote:
>> From: Colin Ian King <colin.king@canonical.com>
>>
>> Currently the loop that calls log_write_hva on each iovec is never
>> executed because of an incorrect error check on the return from the
>> call to translate_desc. The check should be checking for a -ve error
>> return and because it makes no sense to iterate over zero items, the
>> checks should also check for zero too.
>>
>> Detected by CoverityScan, CID#1476969 ("Logically dead code")
>>
>> Fixes: cc5e71075947 ("vhost: log dirty page correctly")
>> Signed-off-by: Colin Ian King <colin.king@canonical.com>
>
> Jason posted a similar patch recently.
>
> Are you happy with that one?
Sure, ignore mine, I was late to the party.
>
>> ---
>> drivers/vhost/vhost.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
>> index 24a129fcdd61..a9a1709a859a 100644
>> --- a/drivers/vhost/vhost.c
>> +++ b/drivers/vhost/vhost.c
>> @@ -1788,7 +1788,7 @@ static int log_used(struct vhost_virtqueue *vq, u64 used_offset, u64 len)
>>
>> ret = translate_desc(vq, (uintptr_t)vq->used + used_offset,
>> len, iov, 64, VHOST_ACCESS_WO);
>> - if (ret)
>> + if (ret <= 0)
>> return ret;
>>
>> for (i = 0; i < ret; i++) {
>> --
>> 2.20.1
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2019-02-19 16:40 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2019-02-19 13:57 [PATCH][next] vhost: only return early if ret indicates an error or no iovecs have been processed Colin King
2019-02-19 16:35 ` Michael S. Tsirkin
2019-02-19 16:40 ` Colin Ian King
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