* [Qemu-devel] [PATCH] vpc: Remove useless parameters in get_sector_offset()
@ 2017-07-13 12:37 Kevin Wolf
2017-07-13 12:42 ` Peter Maydell
0 siblings, 1 reply; 3+ messages in thread
From: Kevin Wolf @ 2017-07-13 12:37 UTC (permalink / raw)
To: qemu-block; +Cc: kwolf, qemu-devel
All callers of get_sector_offset() pass write=false and err=NULL. Remove
the parameters.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
Based on my block branch, specifically Peter's 'block/vpc.c: Handle write
failures in get_image_offset()'
block/vpc.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/block/vpc.c b/block/vpc.c
index bccc981..471f9ab 100644
--- a/block/vpc.c
+++ b/block/vpc.c
@@ -508,10 +508,9 @@ static inline int64_t get_image_offset(BlockDriverState *bs, uint64_t offset,
}
static inline int64_t get_sector_offset(BlockDriverState *bs,
- int64_t sector_num, bool write,
- int *err)
+ int64_t sector_num)
{
- return get_image_offset(bs, sector_num * BDRV_SECTOR_SIZE, write, err);
+ return get_image_offset(bs, sector_num * BDRV_SECTOR_SIZE, false, NULL);
}
/*
@@ -721,7 +720,7 @@ static int64_t coroutine_fn vpc_co_get_block_status(BlockDriverState *bs,
(sector_num << BDRV_SECTOR_BITS);
}
- offset = get_sector_offset(bs, sector_num, false, NULL);
+ offset = get_sector_offset(bs, sector_num);
start = offset;
allocated = (offset != -1);
*pnum = 0;
@@ -744,7 +743,7 @@ static int64_t coroutine_fn vpc_co_get_block_status(BlockDriverState *bs,
if (nb_sectors == 0) {
break;
}
- offset = get_sector_offset(bs, sector_num, false, NULL);
+ offset = get_sector_offset(bs, sector_num);
} while (offset == -1);
return 0;
--
1.8.3.1
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [Qemu-devel] [PATCH] vpc: Remove useless parameters in get_sector_offset()
2017-07-13 12:37 [Qemu-devel] [PATCH] vpc: Remove useless parameters in get_sector_offset() Kevin Wolf
@ 2017-07-13 12:42 ` Peter Maydell
2017-07-13 12:49 ` Kevin Wolf
0 siblings, 1 reply; 3+ messages in thread
From: Peter Maydell @ 2017-07-13 12:42 UTC (permalink / raw)
To: Kevin Wolf; +Cc: Qemu-block, QEMU Developers
On 13 July 2017 at 13:37, Kevin Wolf <kwolf@redhat.com> wrote:
> All callers of get_sector_offset() pass write=false and err=NULL. Remove
> the parameters.
>
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
> Based on my block branch, specifically Peter's 'block/vpc.c: Handle write
> failures in get_image_offset()'
>
> block/vpc.c | 9 ++++-----
> 1 file changed, 4 insertions(+), 5 deletions(-)
>
> diff --git a/block/vpc.c b/block/vpc.c
> index bccc981..471f9ab 100644
> --- a/block/vpc.c
> +++ b/block/vpc.c
> @@ -508,10 +508,9 @@ static inline int64_t get_image_offset(BlockDriverState *bs, uint64_t offset,
> }
>
> static inline int64_t get_sector_offset(BlockDriverState *bs,
> - int64_t sector_num, bool write,
> - int *err)
> + int64_t sector_num)
> {
> - return get_image_offset(bs, sector_num * BDRV_SECTOR_SIZE, write, err);
> + return get_image_offset(bs, sector_num * BDRV_SECTOR_SIZE, false, NULL);
> }
>
> /*
> @@ -721,7 +720,7 @@ static int64_t coroutine_fn vpc_co_get_block_status(BlockDriverState *bs,
> (sector_num << BDRV_SECTOR_BITS);
> }
>
> - offset = get_sector_offset(bs, sector_num, false, NULL);
> + offset = get_sector_offset(bs, sector_num);
> start = offset;
> allocated = (offset != -1);
> *pnum = 0;
> @@ -744,7 +743,7 @@ static int64_t coroutine_fn vpc_co_get_block_status(BlockDriverState *bs,
> if (nb_sectors == 0) {
> break;
> }
> - offset = get_sector_offset(bs, sector_num, false, NULL);
> + offset = get_sector_offset(bs, sector_num);
> } while (offset == -1);
>
> return 0;
Just to copy my remark over from the other thread:
this turns a function that could be used for writes into a function
that doesn't look like it cares whether it's used for reads or
writes but which will actually silently cause disk image
corruption if you do ever use it in a write codepath. That's
a bit of a bear trap as API design goes, which is why I opted
to add the 'err' argument to get_image_offset() rather than
just removing the 'write' argument.
thanks
-- PMM
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [Qemu-devel] [PATCH] vpc: Remove useless parameters in get_sector_offset()
2017-07-13 12:42 ` Peter Maydell
@ 2017-07-13 12:49 ` Kevin Wolf
0 siblings, 0 replies; 3+ messages in thread
From: Kevin Wolf @ 2017-07-13 12:49 UTC (permalink / raw)
To: Peter Maydell; +Cc: Qemu-block, QEMU Developers
Am 13.07.2017 um 14:42 hat Peter Maydell geschrieben:
> On 13 July 2017 at 13:37, Kevin Wolf <kwolf@redhat.com> wrote:
> > All callers of get_sector_offset() pass write=false and err=NULL. Remove
> > the parameters.
> >
> > Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> > ---
> > Based on my block branch, specifically Peter's 'block/vpc.c: Handle write
> > failures in get_image_offset()'
> >
> > block/vpc.c | 9 ++++-----
> > 1 file changed, 4 insertions(+), 5 deletions(-)
> >
> > diff --git a/block/vpc.c b/block/vpc.c
> > index bccc981..471f9ab 100644
> > --- a/block/vpc.c
> > +++ b/block/vpc.c
> > @@ -508,10 +508,9 @@ static inline int64_t get_image_offset(BlockDriverState *bs, uint64_t offset,
> > }
> >
> > static inline int64_t get_sector_offset(BlockDriverState *bs,
> > - int64_t sector_num, bool write,
> > - int *err)
> > + int64_t sector_num)
> > {
> > - return get_image_offset(bs, sector_num * BDRV_SECTOR_SIZE, write, err);
> > + return get_image_offset(bs, sector_num * BDRV_SECTOR_SIZE, false, NULL);
> > }
> >
> > /*
> > @@ -721,7 +720,7 @@ static int64_t coroutine_fn vpc_co_get_block_status(BlockDriverState *bs,
> > (sector_num << BDRV_SECTOR_BITS);
> > }
> >
> > - offset = get_sector_offset(bs, sector_num, false, NULL);
> > + offset = get_sector_offset(bs, sector_num);
> > start = offset;
> > allocated = (offset != -1);
> > *pnum = 0;
> > @@ -744,7 +743,7 @@ static int64_t coroutine_fn vpc_co_get_block_status(BlockDriverState *bs,
> > if (nb_sectors == 0) {
> > break;
> > }
> > - offset = get_sector_offset(bs, sector_num, false, NULL);
> > + offset = get_sector_offset(bs, sector_num);
> > } while (offset == -1);
> >
> > return 0;
>
> Just to copy my remark over from the other thread:
> this turns a function that could be used for writes into a function
> that doesn't look like it cares whether it's used for reads or
> writes but which will actually silently cause disk image
> corruption if you do ever use it in a write codepath. That's
> a bit of a bear trap as API design goes, which is why I opted
> to add the 'err' argument to get_image_offset() rather than
> just removing the 'write' argument.
Not sure if this is a problem in practice, but I'll leave it alone for
now. Once all of Eric's patches are in and make .bdrv_get_block_status
byte-based, the function should just go away anyway.
Kevin
^ permalink raw reply [flat|nested] 3+ messages in thread
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2017-07-13 12:37 [Qemu-devel] [PATCH] vpc: Remove useless parameters in get_sector_offset() Kevin Wolf
2017-07-13 12:42 ` Peter Maydell
2017-07-13 12:49 ` Kevin Wolf
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