[Qemu-devel] [PATCH] 9pfs-proxy: tiny cleanups in proxy_pwritev and proxy_preadv

[Qemu-devel] [PATCH] 9pfs-proxy: tiny cleanups in proxy_pwritev and proxy_preadv

[Michael Tokarev]

Don't compare syscall return with -1, use "<0" condition.
Don't introduce useless local variables when we already
have similar variable
Rename local variable to be consistent with other usages

Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
---
 hw/9pfs/virtio-9p-proxy.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/hw/9pfs/virtio-9p-proxy.c b/hw/9pfs/virtio-9p-proxy.c
index 59c7445..a01804a 100644
--- a/hw/9pfs/virtio-9p-proxy.c
+++ b/hw/9pfs/virtio-9p-proxy.c
@@ -696,9 +696,9 @@ static ssize_t proxy_preadv(FsContext *ctx, V9fsFidOpenState *fs,
 #ifdef CONFIG_PREADV
     return preadv(fs->fd, iov, iovcnt, offset);
 #else
-    int err = lseek(fs->fd, offset, SEEK_SET);
-    if (err == -1) {
-        return err;
+    int ret = lseek(fs->fd, offset, SEEK_SET);
+    if (err < 0)
+        return ret;
     } else {
         return readv(fs->fd, iov, iovcnt);
     }
@@ -714,10 +714,8 @@ static ssize_t proxy_pwritev(FsContext *ctx, V9fsFidOpenState *fs,
 #ifdef CONFIG_PREADV
     ret = pwritev(fs->fd, iov, iovcnt, offset);
 #else
-    int err = lseek(fs->fd, offset, SEEK_SET);
-    if (err == -1) {
-        return err;
-    } else {
+    ret = lseek(fs->fd, offset, SEEK_SET);
+    if (ret >= 0) {
         ret = writev(fs->fd, iov, iovcnt);
     }
 #endif
-- 
2.1.4

Re: [Qemu-devel] [PATCH] 9pfs-proxy: tiny cleanups in proxy_pwritev and proxy_preadv

[Gonglei]

On 2015/3/10 13:54, Michael Tokarev wrote:
> Don't compare syscall return with -1, use "<0" condition.
> Don't introduce useless local variables when we already
> have similar variable
> Rename local variable to be consistent with other usages
> 
> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
> ---
>  hw/9pfs/virtio-9p-proxy.c | 12 +++++-------
>  1 file changed, 5 insertions(+), 7 deletions(-)
> 
> diff --git a/hw/9pfs/virtio-9p-proxy.c b/hw/9pfs/virtio-9p-proxy.c
> index 59c7445..a01804a 100644
> --- a/hw/9pfs/virtio-9p-proxy.c
> +++ b/hw/9pfs/virtio-9p-proxy.c
> @@ -696,9 +696,9 @@ static ssize_t proxy_preadv(FsContext *ctx, V9fsFidOpenState *fs,
>  #ifdef CONFIG_PREADV
>      return preadv(fs->fd, iov, iovcnt, offset);
>  #else
> -    int err = lseek(fs->fd, offset, SEEK_SET);
> -    if (err == -1) {
> -        return err;
> +    int ret = lseek(fs->fd, offset, SEEK_SET);
> +    if (err < 0)
> +        return ret;

The above code fragment is confused.

Regards,
-Gonglei
>      } else {
>          return readv(fs->fd, iov, iovcnt);
>      }
> @@ -714,10 +714,8 @@ static ssize_t proxy_pwritev(FsContext *ctx, V9fsFidOpenState *fs,
>  #ifdef CONFIG_PREADV
>      ret = pwritev(fs->fd, iov, iovcnt, offset);
>  #else
> -    int err = lseek(fs->fd, offset, SEEK_SET);
> -    if (err == -1) {
> -        return err;
> -    } else {
> +    ret = lseek(fs->fd, offset, SEEK_SET);
> +    if (ret >= 0) {
>          ret = writev(fs->fd, iov, iovcnt);
>      }
>  #endif
> 

Re: [Qemu-devel] [PATCH] 9pfs-proxy: tiny cleanups in proxy_pwritev and proxy_preadv

[Michael Tokarev]

10.03.2015 10:15, Gonglei wrote:
> On 2015/3/10 13:54, Michael Tokarev wrote:
>> Don't compare syscall return with -1, use "<0" condition.
>> Don't introduce useless local variables when we already
>> have similar variable
>> Rename local variable to be consistent with other usages
>>
>> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
>> ---
>>  hw/9pfs/virtio-9p-proxy.c | 12 +++++-------
>>  1 file changed, 5 insertions(+), 7 deletions(-)
>>
>> diff --git a/hw/9pfs/virtio-9p-proxy.c b/hw/9pfs/virtio-9p-proxy.c
>> index 59c7445..a01804a 100644
>> --- a/hw/9pfs/virtio-9p-proxy.c
>> +++ b/hw/9pfs/virtio-9p-proxy.c
>> @@ -696,9 +696,9 @@ static ssize_t proxy_preadv(FsContext *ctx, V9fsFidOpenState *fs,
>>  #ifdef CONFIG_PREADV
>>      return preadv(fs->fd, iov, iovcnt, offset);
>>  #else
>> -    int err = lseek(fs->fd, offset, SEEK_SET);
>> -    if (err == -1) {
>> -        return err;
>> +    int ret = lseek(fs->fd, offset, SEEK_SET);
>> +    if (err < 0)
>> +        return ret;
> 
> The above code fragment is confused.

Sorry I don't understand, can you elaborate please?
Note I haven't changed much in there, just variable
rename and changed the condition within if: s/== -1/< 0/.

(BTW, a code fragment can't be confused, it might be
confusing I think, with a reader being confused.
A confused code is um.. something -- a code who doesn't
know what to do... ;)  Sorry can't resist ;)

Thanks,

/mjt

Re: [Qemu-devel] [PATCH] 9pfs-proxy: tiny cleanups in proxy_pwritev and proxy_preadv

[Gonglei]

On 2015/3/10 15:20, Michael Tokarev wrote:
> 10.03.2015 10:15, Gonglei wrote:
>> On 2015/3/10 13:54, Michael Tokarev wrote:
>>> Don't compare syscall return with -1, use "<0" condition.
>>> Don't introduce useless local variables when we already
>>> have similar variable
>>> Rename local variable to be consistent with other usages
>>>
>>> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
>>> ---
>>>  hw/9pfs/virtio-9p-proxy.c | 12 +++++-------
>>>  1 file changed, 5 insertions(+), 7 deletions(-)
>>>
>>> diff --git a/hw/9pfs/virtio-9p-proxy.c b/hw/9pfs/virtio-9p-proxy.c
>>> index 59c7445..a01804a 100644
>>> --- a/hw/9pfs/virtio-9p-proxy.c
>>> +++ b/hw/9pfs/virtio-9p-proxy.c
>>> @@ -696,9 +696,9 @@ static ssize_t proxy_preadv(FsContext *ctx, V9fsFidOpenState *fs,
>>>  #ifdef CONFIG_PREADV
>>>      return preadv(fs->fd, iov, iovcnt, offset);
>>>  #else
>>> -    int err = lseek(fs->fd, offset, SEEK_SET);
>>> -    if (err == -1) {
>>> -        return err;
>>> +    int ret = lseek(fs->fd, offset, SEEK_SET);
>>> +    if (err < 0)
>>> +        return ret;
>>
>> The above code fragment is confused.
> 
> Sorry I don't understand, can you elaborate please?
> Note I haven't changed much in there, just variable
> rename and changed the condition within if: s/== -1/< 0/.
> 
You use 'ret' instead of 'err', but remain using 'if (err < 0)',
and missing '{' at the end of if statement.

hw/9pfs/virtio-9p-proxy.c: In function ‘proxy_preadv’:
hw/9pfs/virtio-9p-proxy.c:700: error: ‘err’ undeclared (first use in this function)
hw/9pfs/virtio-9p-proxy.c:700: error: (Each undeclared identifier is reported only once
hw/9pfs/virtio-9p-proxy.c:700: error: for each function it appears in.)
hw/9pfs/virtio-9p-proxy.c:702: warning: control reaches end of non-void function
hw/9pfs/virtio-9p-proxy.c: At top level:
hw/9pfs/virtio-9p-proxy.c:702: error: expected identifier or ‘(’ before ‘else’
hw/9pfs/virtio-9p-proxy.c:706: error: expected identifier or ‘(’ before ‘}’ token
make: *** [hw/9pfs/virtio-9p-proxy.o] Error 1

Regards,
-Gonglei
> (BTW, a code fragment can't be confused, it might be
> confusing I think, with a reader being confused.
> A confused code is um.. something -- a code who doesn't
> know what to do... ;)  Sorry can't resist ;)
> 
> Thanks,
> 
> /mjt
> 

Re: [Qemu-devel] [PATCH] 9pfs-proxy: tiny cleanups in proxy_pwritev and proxy_preadv

[Aneesh Kumar K.V]

Michael Tokarev <mjt@tls.msk.ru> writes:

> Don't compare syscall return with -1, use "<0" condition.
> Don't introduce useless local variables when we already
> have similar variable
> Rename local variable to be consistent with other usages
>
> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
> ---
>  hw/9pfs/virtio-9p-proxy.c | 12 +++++-------
>  1 file changed, 5 insertions(+), 7 deletions(-)
>
> diff --git a/hw/9pfs/virtio-9p-proxy.c b/hw/9pfs/virtio-9p-proxy.c
> index 59c7445..a01804a 100644
> --- a/hw/9pfs/virtio-9p-proxy.c
> +++ b/hw/9pfs/virtio-9p-proxy.c
> @@ -696,9 +696,9 @@ static ssize_t proxy_preadv(FsContext *ctx, V9fsFidOpenState *fs,
>  #ifdef CONFIG_PREADV
>      return preadv(fs->fd, iov, iovcnt, offset);
>  #else
> -    int err = lseek(fs->fd, offset, SEEK_SET);
> -    if (err == -1) {
> -        return err;
> +    int ret = lseek(fs->fd, offset, SEEK_SET);
> +    if (err < 0)
> +        return ret;
>      } else {
>          return readv(fs->fd, iov, iovcnt);
>      }

I am not sure this is needed, whether to use int err or int ret as the
variable name is simply a matter of preference for the author. Also did
you compile test the above ? (note: int ret followed by a check with
variable name 'err').


> @@ -714,10 +714,8 @@ static ssize_t proxy_pwritev(FsContext *ctx, V9fsFidOpenState *fs,
>  #ifdef CONFIG_PREADV
>      ret = pwritev(fs->fd, iov, iovcnt, offset);
>  #else
> -    int err = lseek(fs->fd, offset, SEEK_SET);
> -    if (err == -1) {
> -        return err;
> -    } else {
> +    ret = lseek(fs->fd, offset, SEEK_SET);
> +    if (ret >= 0) {
>          ret = writev(fs->fd, iov, iovcnt);
>      }
>  #endif

-aneesh

Re: [Qemu-devel] [PATCH] 9pfs-proxy: tiny cleanups in proxy_pwritev and proxy_preadv

[Michael Tokarev]

10.03.2015 20:23, Aneesh Kumar K.V wrote:
[]>
> I am not sure this is needed, whether to use int err or int ret as the
> variable name is simply a matter of preference for the author.

We have 2 filesystem methods in here, read and write, one near another,
which are written by the same author (but one of them has been later
extended a bit, adding another variable).  This patch makes them similar
again.

>   Also did
> you compile test the above ? (note: int ret followed by a check with
> variable name 'err').

Well yes.  It is a forgotten git commit.  Ofcourse I verified the result,
I just forgot to commit because I was distracted by something else, hence
sent a wrong patch.  I'll resend it.

/mjt