| Message ID | 20200916165748.20927-1-alex.dewar90@gmail.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | dbeb101d28eb89a9138055b50d5ce7a9f7a663cf |
| Delegated to: | Kalle Valo |
| Headers | show |
| Series | [v2] ath10k: sdio: remove redundant check in for loop | expand |
Hi Alex, On Thu, Sep 17, 2020 at 3:09 AM Alex Dewar <alex.dewar90@gmail.com> wrote: > > The for loop checks whether cur_section is NULL on every iteration, but > we know it can never be NULL as there is another check towards the > bottom of the loop body. Refactor to avoid this unnecessary check. > > Also, increment the variable i inline for clarity Comments below. > Addresses-Coverity: 1496984 ("Null pointer dereferences) > Suggested-by: Saeed Mahameed <saeedm@nvidia.com> > Signed-off-by: Alex Dewar <alex.dewar90@gmail.com> > --- > v2: refactor in the manner suggested by Saeed > > drivers/net/wireless/ath/ath10k/sdio.c | 12 +++--------- > 1 file changed, 3 insertions(+), 9 deletions(-) > > diff --git a/drivers/net/wireless/ath/ath10k/sdio.c b/drivers/net/wireless/ath/ath10k/sdio.c > index 81ddaafb6721..486886c74e6a 100644 > --- a/drivers/net/wireless/ath/ath10k/sdio.c > +++ b/drivers/net/wireless/ath/ath10k/sdio.c > @@ -2307,8 +2307,8 @@ static int ath10k_sdio_dump_memory_section(struct ath10k *ar, > } > > count = 0; > - > - for (i = 0; cur_section; i++) { > + i = 0; > + for (; cur_section; cur_section = next_section) { You can have multiple statements in each section of a for() if you need to, e.g. for (i = 1; cur_section; cur_section = next_section, i++) { which means that the increment of i isn't hidden deep in the function body. That said, this function is a mess. Something (approximately) like this might be more readable: prev_end = memregion->start; for (i = 0; i < mem_region->section_table.size; i++) { cur_section = &mem_region->section_table.sections[i]; // fail if prev_end is greater than cur_section->start - message from line 2329 and 2294 // check section size - from line 2315 skip_size = cur_section->start - prev_end; // check buffer size - from line 2339 - needs to account for the skip size too. // fill in the skip size amount - from line 2358 and 2304 // ath10k_sdio_read_mem - from line 2346 prev_end = cur_section->end; } Thanks,
Julian Calaby <julian.calaby@gmail.com> writes: > On Thu, Sep 17, 2020 at 3:09 AM Alex Dewar <alex.dewar90@gmail.com> wrote: >> >> The for loop checks whether cur_section is NULL on every iteration, but >> we know it can never be NULL as there is another check towards the >> bottom of the loop body. Refactor to avoid this unnecessary check. >> >> Also, increment the variable i inline for clarity > > Comments below. > >> Addresses-Coverity: 1496984 ("Null pointer dereferences) >> Suggested-by: Saeed Mahameed <saeedm@nvidia.com> >> Signed-off-by: Alex Dewar <alex.dewar90@gmail.com> >> --- >> v2: refactor in the manner suggested by Saeed >> >> drivers/net/wireless/ath/ath10k/sdio.c | 12 +++--------- >> 1 file changed, 3 insertions(+), 9 deletions(-) >> >> diff --git a/drivers/net/wireless/ath/ath10k/sdio.c b/drivers/net/wireless/ath/ath10k/sdio.c >> index 81ddaafb6721..486886c74e6a 100644 >> --- a/drivers/net/wireless/ath/ath10k/sdio.c >> +++ b/drivers/net/wireless/ath/ath10k/sdio.c >> @@ -2307,8 +2307,8 @@ static int ath10k_sdio_dump_memory_section(struct ath10k *ar, >> } >> >> count = 0; >> - >> - for (i = 0; cur_section; i++) { >> + i = 0; >> + for (; cur_section; cur_section = next_section) { > > You can have multiple statements in each section of a for() if you need to, e.g. > > for (i = 1; cur_section; cur_section = next_section, i++) { > > which means that the increment of i isn't hidden deep in the function body. Yeah, I was thinking the same. But I'll apply this patch anyway, it's still an improvement. > That said, this function is a mess. Something (approximately) like > this might be more readable: > > prev_end = memregion->start; > for (i = 0; i < mem_region->section_table.size; i++) { > cur_section = &mem_region->section_table.sections[i]; > > // fail if prev_end is greater than cur_section->start - message > from line 2329 and 2294 > // check section size - from line 2315 > > skip_size = cur_section->start - prev_end; > > // check buffer size - from line 2339 - needs to account for the > skip size too. > // fill in the skip size amount - from line 2358 and 2304 > // ath10k_sdio_read_mem - from line 2346 > > prev_end = cur_section->end; > } I agree. Anyone can come up with a patch?
> I agree. Anyone can come up with a patch? Hi Kalle, I was thinking of having a go at this. Have you applied the v2 of this patch yet though? I couldn't see it in wireless-drivers-next. I just don't want to have to rebase the patch if you were going to apply this v2. Best, Alex > > -- > https://patchwork.kernel.org/project/linux-wireless/list/ > > https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
Alex Dewar <alex.dewar90@gmail.com> writes: >> I agree. Anyone can come up with a patch? > > Hi Kalle, > > I was thinking of having a go at this. Have you applied the v2 of this > patch yet though? I couldn't see it in wireless-drivers-next. I just > don't want to have to rebase the patch if you were going to apply this > v2. I have not applied this yet. It's in my pending branch but I can easily drop it. Just let me know what you prefer.
Alex Dewar <alex.dewar90@gmail.com> wrote: > The for loop checks whether cur_section is NULL on every iteration, but > we know it can never be NULL as there is another check towards the > bottom of the loop body. Refactor to avoid this unnecessary check. > > Also, increment the variable i inline for clarity > > Addresses-Coverity: 1496984 ("Null pointer dereferences) > Suggested-by: Saeed Mahameed <saeedm@nvidia.com> > Signed-off-by: Alex Dewar <alex.dewar90@gmail.com> > Signed-off-by: Kalle Valo <kvalo@codeaurora.org> Patch applied to ath-next branch of ath.git, thanks. dbeb101d28eb ath10k: sdio: remove redundant check in for loop
diff --git a/drivers/net/wireless/ath/ath10k/sdio.c b/drivers/net/wireless/ath/ath10k/sdio.c index 81ddaafb6721..486886c74e6a 100644 --- a/drivers/net/wireless/ath/ath10k/sdio.c +++ b/drivers/net/wireless/ath/ath10k/sdio.c @@ -2307,8 +2307,8 @@ static int ath10k_sdio_dump_memory_section(struct ath10k *ar, } count = 0; - - for (i = 0; cur_section; i++) { + i = 0; + for (; cur_section; cur_section = next_section) { section_size = cur_section->end - cur_section->start; if (section_size <= 0) { @@ -2318,7 +2318,7 @@ static int ath10k_sdio_dump_memory_section(struct ath10k *ar, break; } - if ((i + 1) == mem_region->section_table.size) { + if (++i == mem_region->section_table.size) { /* last section */ next_section = NULL; skip_size = 0; @@ -2361,12 +2361,6 @@ static int ath10k_sdio_dump_memory_section(struct ath10k *ar, } count += skip_size; - - if (!next_section) - /* this was the last section */ - break; - - cur_section = next_section; } return count;
The for loop checks whether cur_section is NULL on every iteration, but we know it can never be NULL as there is another check towards the bottom of the loop body. Refactor to avoid this unnecessary check. Also, increment the variable i inline for clarity Addresses-Coverity: 1496984 ("Null pointer dereferences) Suggested-by: Saeed Mahameed <saeedm@nvidia.com> Signed-off-by: Alex Dewar <alex.dewar90@gmail.com> --- v2: refactor in the manner suggested by Saeed drivers/net/wireless/ath/ath10k/sdio.c | 12 +++--------- 1 file changed, 3 insertions(+), 9 deletions(-)