On 4/9/22 3:19 AM, Michal Orzel wrote:
> Get rid of redundant assignments which end up in values not being
> read either because they are overwritten or the function ends.
This log is the same as your last patch.
Instead of a general statement on deadstores, a more specific
analysis of the setting being removed would be helpful.
This will mean splitting the patch to match the analysis.
Tom
>
> Reported by clang-tidy [deadcode.DeadStores]
>
> Signed-off-by: Michal Orzel <[email protected]>
> ---
> block/badblocks.c | 2 --
> block/blk-map.c | 5 ++---
> block/partitions/acorn.c | 4 ++--
> block/partitions/atari.c | 1 -
> block/partitions/ldm.c | 15 +++------------
> 5 files changed, 7 insertions(+), 20 deletions(-)
>
> diff --git a/block/badblocks.c b/block/badblocks.c
> index d39056630d9c..3afb550c0f7b 100644
> --- a/block/badblocks.c
> +++ b/block/badblocks.c
> @@ -65,7 +65,6 @@ int badblocks_check(struct badblocks *bb, sector_t s, int sectors,
> s >>= bb->shift;
> target += (1<<bb->shift) - 1;
> target >>= bb->shift;
> - sectors = target - s;
> }
> /* 'target' is now the first block after the bad range */
>
> @@ -345,7 +344,6 @@ int badblocks_clear(struct badblocks *bb, sector_t s, int sectors)
> s += (1<<bb->shift) - 1;
> s >>= bb->shift;
> target >>= bb->shift;
> - sectors = target - s;
> }
>
> write_seqlock_irq(&bb->lock);
> diff --git a/block/blk-map.c b/block/blk-map.c
> index c7f71d83eff1..fa72e63e18c2 100644
> --- a/block/blk-map.c
> +++ b/block/blk-map.c
> @@ -260,10 +260,9 @@ static int bio_map_user_iov(struct request *rq, struct iov_iter *iter,
>
> npages = DIV_ROUND_UP(offs + bytes, PAGE_SIZE);
>
> - if (unlikely(offs & queue_dma_alignment(rq->q))) {
> - ret = -EINVAL;
> + if (unlikely(offs & queue_dma_alignment(rq->q)))
> j = 0;
> - } else {
> + else {
> for (j = 0; j < npages; j++) {
> struct page *page = pages[j];
> unsigned int n = PAGE_SIZE - offs;
> diff --git a/block/partitions/acorn.c b/block/partitions/acorn.c
> index 2c381c694c57..d2fc122d7426 100644
> --- a/block/partitions/acorn.c
> +++ b/block/partitions/acorn.c
> @@ -282,13 +282,13 @@ int adfspart_check_ADFS(struct parsed_partitions *state)
> #ifdef CONFIG_ACORN_PARTITION_RISCIX
> case PARTITION_RISCIX_SCSI:
> case PARTITION_RISCIX_MFM:
> - slot = riscix_partition(state, start_sect, slot,
> + riscix_partition(state, start_sect, slot,
> nr_sects);
> break;
> #endif
>
> case PARTITION_LINUX:
> - slot = linux_partition(state, start_sect, slot,
> + linux_partition(state, start_sect, slot,
> nr_sects);
> break;
> }
> diff --git a/block/partitions/atari.c b/block/partitions/atari.c
> index da5994175416..9655c728262a 100644
> --- a/block/partitions/atari.c
> +++ b/block/partitions/atari.c
> @@ -140,7 +140,6 @@ int atari_partition(struct parsed_partitions *state)
> /* accept only GEM,BGM,RAW,LNX,SWP partitions */
> if (!((pi->flg & 1) && OK_id(pi->id)))
> continue;
> - part_fmt = 2;
> put_partition (state, slot,
> be32_to_cpu(pi->st),
> be32_to_cpu(pi->siz));
> diff --git a/block/partitions/ldm.c b/block/partitions/ldm.c
> index 27f6c7d9c776..38e58960ae03 100644
> --- a/block/partitions/ldm.c
> +++ b/block/partitions/ldm.c
> @@ -736,7 +736,6 @@ static bool ldm_parse_cmp3 (const u8 *buffer, int buflen, struct vblk *vb)
> len = r_cols;
> } else {
> r_stripe = 0;
> - r_cols = 0;
> len = r_parent;
> }
> if (len < 0)
> @@ -783,11 +782,8 @@ static int ldm_parse_dgr3 (const u8 *buffer, int buflen, struct vblk *vb)
> r_id1 = ldm_relative (buffer, buflen, 0x24, r_diskid);
> r_id2 = ldm_relative (buffer, buflen, 0x24, r_id1);
> len = r_id2;
> - } else {
> - r_id1 = 0;
> - r_id2 = 0;
> + } else
> len = r_diskid;
> - }
> if (len < 0)
> return false;
>
> @@ -826,11 +822,8 @@ static bool ldm_parse_dgr4 (const u8 *buffer, int buflen, struct vblk *vb)
> r_id1 = ldm_relative (buffer, buflen, 0x44, r_name);
> r_id2 = ldm_relative (buffer, buflen, 0x44, r_id1);
> len = r_id2;
> - } else {
> - r_id1 = 0;
> - r_id2 = 0;
> + } else
> len = r_name;
> - }
> if (len < 0)
> return false;
>
> @@ -963,10 +956,8 @@ static bool ldm_parse_prt3(const u8 *buffer, int buflen, struct vblk *vb)
> return false;
> }
> len = r_index;
> - } else {
> - r_index = 0;
> + } else
> len = r_diskid;
> - }
> if (len < 0) {
> ldm_error("len %d < 0", len);
> return false;
Hi Tom,
>
> On 4/9/22 3:19 AM, Michal Orzel wrote:
>> Get rid of redundant assignments which end up in values not being
>> read either because they are overwritten or the function ends.
>
> This log is the same as your last patch.
>
> Instead of a general statement on deadstores, a more specific
>
> analysis of the setting being removed would be helpful.
>
> This will mean splitting the patch to match the analysis.
>
> Tom
>
I think that this explanation in a commit is enough for such a trivial patch.
It informs that we are fixing clang-tidy findings related to deadstores
in a block subsystem. What analysis would you want to see?
Something like "Remove deadstore assignment ret = -EINVAL in a function bio_map_user_iov" ?
I think that it will create too much of not needed overhead.
Cheers,
Michal
On 4/9/22 6:20 AM, Michal Orzel wrote:
> Hi Tom,
>
>> On 4/9/22 3:19 AM, Michal Orzel wrote:
>>> Get rid of redundant assignments which end up in values not being
>>> read either because they are overwritten or the function ends.
>> This log is the same as your last patch.
>>
>> Instead of a general statement on deadstores, a more specific
>>
>> analysis of the setting being removed would be helpful.
>>
>> This will mean splitting the patch to match the analysis.
>>
>> Tom
>>
> I think that this explanation in a commit is enough for such a trivial patch.
> It informs that we are fixing clang-tidy findings related to deadstores
> in a block subsystem. What analysis would you want to see?
> Something like "Remove deadstore assignment ret = -EINVAL in a function bio_map_user_iov" ?
> I think that it will create too much of not needed overhead.
The compiler should remove these already. All of the static analyzers
produce false positives, if you do not provide analysis the reviewer has
to assume you have not done any and has to do the false positive
analysis themselves. This burdens the reviewer for something of small
value that can be dismissed as churn.
Tom
>
> Cheers,
> Michal
>