[PATCH 1/2] drm/panic: use `div_ceil` to clean Clippy warning

[PATCH 1/2] drm/panic: use `div_ceil` to clean Clippy warning

[Miguel Ojeda]

Starting with the upcoming Rust 1.86.0 (to be released 2025-04-03),
Clippy warns:

    error: manually reimplementing `div_ceil`
       --> drivers/gpu/drm/drm_panic_qr.rs:548:26
        |
    548 |         let pad_offset = (offset + 7) / 8;
        |                          ^^^^^^^^^^^^^^^^ help: consider using `.div_ceil()`: `offset.div_ceil(8)`
        |
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#manual_div_ceil

And similarly for `stride`. Thus apply the suggestion to both.

The behavior (and thus codegen) is not exactly equivalent [1][2], since
`div_ceil()` returns the right value for the values that currently
would overflow.

Link: https://github.com/rust-lang/rust-clippy/issues/14333 [1]
Link: https://godbolt.org/z/dPq6nGnv3 [2]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
 drivers/gpu/drm/drm_panic_qr.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_panic_qr.rs b/drivers/gpu/drm/drm_panic_qr.rs
index bcf248f69252..8bb5e52d75cc 100644
--- a/drivers/gpu/drm/drm_panic_qr.rs
+++ b/drivers/gpu/drm/drm_panic_qr.rs
@@ -545,7 +545,7 @@ fn add_segments(&mut self, segments: &[&Segment<'_>]) {
         }
         self.push(&mut offset, (MODE_STOP, 4));
 
-        let pad_offset = (offset + 7) / 8;
+        let pad_offset = offset.div_ceil(8);
         for i in pad_offset..self.version.max_data() {
             self.data[i] = PADDING[(i & 1) ^ (pad_offset & 1)];
         }
@@ -659,7 +659,7 @@ struct QrImage<'a> {
 impl QrImage<'_> {
     fn new<'a, 'b>(em: &'b EncodedMsg<'b>, qrdata: &'a mut [u8]) -> QrImage<'a> {
         let width = em.version.width();
-        let stride = (width + 7) / 8;
+        let stride = width.div_ceil(8);
         let data = qrdata;
 
         let mut qr_image = QrImage {

base-commit: d082ecbc71e9e0bf49883ee4afd435a77a5101b6
-- 
2.48.1

[PATCH 2/2] drm/panic: fix overindented list items in documentation

[Miguel Ojeda]

Starting with the upcoming Rust 1.86.0 (to be released 2025-04-03),
Clippy warns:

    error: doc list item overindented
       --> drivers/gpu/drm/drm_panic_qr.rs:914:5
        |
    914 | ///    will be encoded as binary segment, otherwise it will be encoded
        |     ^^^ help: try using `  ` (2 spaces)
        |
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#doc_overindented_list_items

The overindentation is slightly hard to notice, since all the items
start with a backquote that makes it look OK, but it is there.

Thus fix it.

Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
 drivers/gpu/drm/drm_panic_qr.rs | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/drm_panic_qr.rs b/drivers/gpu/drm/drm_panic_qr.rs
index 8bb5e52d75cc..6903e2010cb9 100644
--- a/drivers/gpu/drm/drm_panic_qr.rs
+++ b/drivers/gpu/drm/drm_panic_qr.rs
@@ -911,16 +911,16 @@ fn draw_all(&mut self, data: impl Iterator<Item = u8>) {
 ///
 /// * `url`: The base URL of the QR code. It will be encoded as Binary segment.
 /// * `data`: A pointer to the binary data, to be encoded. if URL is NULL, it
-///    will be encoded as binary segment, otherwise it will be encoded
-///    efficiently as a numeric segment, and appended to the URL.
+///   will be encoded as binary segment, otherwise it will be encoded
+///   efficiently as a numeric segment, and appended to the URL.
 /// * `data_len`: Length of the data, that needs to be encoded, must be less
-///    than data_size.
+///   than data_size.
 /// * `data_size`: Size of data buffer, it should be at least 4071 bytes to hold
-///    a V40 QR code. It will then be overwritten with the QR code image.
+///   a V40 QR code. It will then be overwritten with the QR code image.
 /// * `tmp`: A temporary buffer that the QR code encoder will use, to write the
-///    segments and ECC.
+///   segments and ECC.
 /// * `tmp_size`: Size of the temporary buffer, it must be at least 3706 bytes
-///    long for V40.
+///   long for V40.
 ///
 /// # Safety
 ///
-- 
2.48.1

Re: [PATCH 2/2] drm/panic: fix overindented list items in documentation

[Miguel Ojeda]

On Sun, Mar 2, 2025 at 12:17 AM Miguel Ojeda <ojeda@kernel.org> wrote:
>
> Starting with the upcoming Rust 1.86.0 (to be released 2025-04-03),
> Clippy warns:
>
>     error: doc list item overindented
>        --> drivers/gpu/drm/drm_panic_qr.rs:914:5
>         |
>     914 | ///    will be encoded as binary segment, otherwise it will be encoded
>         |     ^^^ help: try using `  ` (2 spaces)
>         |
>         = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#doc_overindented_list_items
>
> The overindentation is slightly hard to notice, since all the items
> start with a backquote that makes it look OK, but it is there.
>
> Thus fix it.
>
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Fixes: cb5164ac43d0 ("drm/panic: Add a QR code panic screen")
Cc: stable@vger.kernel.org # Needed in 6.12.y and 6.13.y only (Rust is
pinned in older LTSs).

Cheers,
Miguel

Re: [PATCH 2/2] drm/panic: fix overindented list items in documentation

[Jarkko Sakkinen]

On Sun, Mar 02, 2025 at 07:54:00AM +0100, Miguel Ojeda wrote:
> On Sun, Mar 2, 2025 at 12:17 AM Miguel Ojeda <ojeda@kernel.org> wrote:
> >
> > Starting with the upcoming Rust 1.86.0 (to be released 2025-04-03),
> > Clippy warns:
> >
> >     error: doc list item overindented
> >        --> drivers/gpu/drm/drm_panic_qr.rs:914:5
> >         |
> >     914 | ///    will be encoded as binary segment, otherwise it will be encoded
> >         |     ^^^ help: try using `  ` (2 spaces)
> >         |
> >         = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#doc_overindented_list_items
> >
> > The overindentation is slightly hard to notice, since all the items
> > start with a backquote that makes it look OK, but it is there.
> >
> > Thus fix it.
> >
> > Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
> 
> Fixes: cb5164ac43d0 ("drm/panic: Add a QR code panic screen")
> Cc: stable@vger.kernel.org # Needed in 6.12.y and 6.13.y only (Rust is
> pinned in older LTSs).

(cosmetic) Nit:

I think you could just:

Cc: stable@vger.kernel.org # v6.12+

> 
> Cheers,
> Miguel
> 

BR, Jarkko

Re: [PATCH 2/2] drm/panic: fix overindented list items in documentation

[Miguel Ojeda]

On Sun, Mar 2, 2025 at 5:50 PM Jarkko Sakkinen <jarkko@kernel.org> wrote:
>
> (cosmetic) Nit:
>
> I think you could just:
>
> Cc: stable@vger.kernel.org # v6.12+

Thanks Jarkko -- I did something similar in the past, but sometimes
patches got backported too much because they could be applied.

Normally they don't hurt, but I try to be more explicit nowadays so
that the stable team can decide, and thus I copy-paste that line for
changes that are related to new compiler cleanups and similar.

Cheers,
Miguel

Re: [PATCH 2/2] drm/panic: fix overindented list items in documentation

[Jarkko Sakkinen]

On Sun, Mar 02, 2025 at 06:45:13PM +0100, Miguel Ojeda wrote:
> On Sun, Mar 2, 2025 at 5:50 PM Jarkko Sakkinen <jarkko@kernel.org> wrote:
> >
> > (cosmetic) Nit:
> >
> > I think you could just:
> >
> > Cc: stable@vger.kernel.org # v6.12+
> 
> Thanks Jarkko -- I did something similar in the past, but sometimes
> patches got backported too much because they could be applied.
> 
> Normally they don't hurt, but I try to be more explicit nowadays so
> that the stable team can decide, and thus I copy-paste that line for
> changes that are related to new compiler cleanups and similar.

Ah, ok, I guessed that you might have some backing idea on what you put
:-) Thanks for the explanation.

> 
> Cheers,
> Miguel
> 

BR, Jarkko

Re: [PATCH 2/2] drm/panic: fix overindented list items in documentation

[Miguel Ojeda]

On Sun, Mar 2, 2025 at 7:31 PM Jarkko Sakkinen <jarkko@kernel.org> wrote:
>
> Ah, ok, I guessed that you might have some backing idea on what you put
> :-) Thanks for the explanation.

You're welcome!

Cheers,
Miguel

Re: [PATCH 2/2] drm/panic: fix overindented list items in documentation

[Alice Ryhl]

On Sun, Mar 2, 2025 at 12:17 AM Miguel Ojeda <ojeda@kernel.org> wrote:
>
> Starting with the upcoming Rust 1.86.0 (to be released 2025-04-03),
> Clippy warns:
>
>     error: doc list item overindented
>        --> drivers/gpu/drm/drm_panic_qr.rs:914:5
>         |
>     914 | ///    will be encoded as binary segment, otherwise it will be encoded
>         |     ^^^ help: try using `  ` (2 spaces)
>         |
>         = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#doc_overindented_list_items
>
> The overindentation is slightly hard to notice, since all the items
> start with a backquote that makes it look OK, but it is there.
>
> Thus fix it.
>
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Reviewed-by: Alice Ryhl <aliceryhl@google.com>

Re: [PATCH 2/2] drm/panic: fix overindented list items in documentation

[Jocelyn Falempe]

On 02/03/2025 00:16, Miguel Ojeda wrote:
> Starting with the upcoming Rust 1.86.0 (to be released 2025-04-03),
> Clippy warns:
> 
>      error: doc list item overindented
>         --> drivers/gpu/drm/drm_panic_qr.rs:914:5
>          |
>      914 | ///    will be encoded as binary segment, otherwise it will be encoded
>          |     ^^^ help: try using `  ` (2 spaces)
>          |
>          = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#doc_overindented_list_items
> 
> The overindentation is slightly hard to notice, since all the items
> start with a backquote that makes it look OK, but it is there.
> 
> Thus fix it.

Thanks, it looks good to me.

Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>

> 
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
> ---
>   drivers/gpu/drm/drm_panic_qr.rs | 12 ++++++------
>   1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_panic_qr.rs b/drivers/gpu/drm/drm_panic_qr.rs
> index 8bb5e52d75cc..6903e2010cb9 100644
> --- a/drivers/gpu/drm/drm_panic_qr.rs
> +++ b/drivers/gpu/drm/drm_panic_qr.rs
> @@ -911,16 +911,16 @@ fn draw_all(&mut self, data: impl Iterator<Item = u8>) {
>   ///
>   /// * `url`: The base URL of the QR code. It will be encoded as Binary segment.
>   /// * `data`: A pointer to the binary data, to be encoded. if URL is NULL, it
> -///    will be encoded as binary segment, otherwise it will be encoded
> -///    efficiently as a numeric segment, and appended to the URL.
> +///   will be encoded as binary segment, otherwise it will be encoded
> +///   efficiently as a numeric segment, and appended to the URL.
>   /// * `data_len`: Length of the data, that needs to be encoded, must be less
> -///    than data_size.
> +///   than data_size.
>   /// * `data_size`: Size of data buffer, it should be at least 4071 bytes to hold
> -///    a V40 QR code. It will then be overwritten with the QR code image.
> +///   a V40 QR code. It will then be overwritten with the QR code image.
>   /// * `tmp`: A temporary buffer that the QR code encoder will use, to write the
> -///    segments and ECC.
> +///   segments and ECC.
>   /// * `tmp_size`: Size of the temporary buffer, it must be at least 3706 bytes
> -///    long for V40.
> +///   long for V40.
>   ///
>   /// # Safety
>   ///

Re: [PATCH 1/2] drm/panic: use `div_ceil` to clean Clippy warning

[Miguel Ojeda]

On Sun, Mar 2, 2025 at 12:17 AM Miguel Ojeda <ojeda@kernel.org> wrote:
>
> Starting with the upcoming Rust 1.86.0 (to be released 2025-04-03),
> Clippy warns:
>
>     error: manually reimplementing `div_ceil`
>        --> drivers/gpu/drm/drm_panic_qr.rs:548:26
>         |
>     548 |         let pad_offset = (offset + 7) / 8;
>         |                          ^^^^^^^^^^^^^^^^ help: consider using `.div_ceil()`: `offset.div_ceil(8)`
>         |
>         = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#manual_div_ceil
>
> And similarly for `stride`. Thus apply the suggestion to both.
>
> The behavior (and thus codegen) is not exactly equivalent [1][2], since
> `div_ceil()` returns the right value for the values that currently
> would overflow.
>
> Link: https://github.com/rust-lang/rust-clippy/issues/14333 [1]
> Link: https://godbolt.org/z/dPq6nGnv3 [2]
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Cc: stable@vger.kernel.org # Needed in 6.12.y and 6.13.y only (Rust is
pinned in older LTSs).

Cheers,
Miguel

Re: [PATCH 1/2] drm/panic: use `div_ceil` to clean Clippy warning

[Alice Ryhl]

On Sun, Mar 2, 2025 at 12:17 AM Miguel Ojeda <ojeda@kernel.org> wrote:
>
> Starting with the upcoming Rust 1.86.0 (to be released 2025-04-03),
> Clippy warns:
>
>     error: manually reimplementing `div_ceil`
>        --> drivers/gpu/drm/drm_panic_qr.rs:548:26
>         |
>     548 |         let pad_offset = (offset + 7) / 8;
>         |                          ^^^^^^^^^^^^^^^^ help: consider using `.div_ceil()`: `offset.div_ceil(8)`
>         |
>         = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#manual_div_ceil
>
> And similarly for `stride`. Thus apply the suggestion to both.
>
> The behavior (and thus codegen) is not exactly equivalent [1][2], since
> `div_ceil()` returns the right value for the values that currently
> would overflow.
>
> Link: https://github.com/rust-lang/rust-clippy/issues/14333 [1]
> Link: https://godbolt.org/z/dPq6nGnv3 [2]
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Reviewed-by: Alice Ryhl <aliceryhl@google.com>

Re: [PATCH 1/2] drm/panic: use `div_ceil` to clean Clippy warning

[Jocelyn Falempe]

On 02/03/2025 00:16, Miguel Ojeda wrote:
> Starting with the upcoming Rust 1.86.0 (to be released 2025-04-03),
> Clippy warns:
> 
>      error: manually reimplementing `div_ceil`
>         --> drivers/gpu/drm/drm_panic_qr.rs:548:26
>          |
>      548 |         let pad_offset = (offset + 7) / 8;
>          |                          ^^^^^^^^^^^^^^^^ help: consider using `.div_ceil()`: `offset.div_ceil(8)`
>          |
>          = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#manual_div_ceil
> 
> And similarly for `stride`. Thus apply the suggestion to both.
> 
> The behavior (and thus codegen) is not exactly equivalent [1][2], since
> `div_ceil()` returns the right value for the values that currently
> would overflow.

Thanks, so that's the DIV_ROUND_UP equivalent I was looking for.

Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>

> 
> Link: https://github.com/rust-lang/rust-clippy/issues/14333 [1]
> Link: https://godbolt.org/z/dPq6nGnv3 [2]
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
> ---
>   drivers/gpu/drm/drm_panic_qr.rs | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_panic_qr.rs b/drivers/gpu/drm/drm_panic_qr.rs
> index bcf248f69252..8bb5e52d75cc 100644
> --- a/drivers/gpu/drm/drm_panic_qr.rs
> +++ b/drivers/gpu/drm/drm_panic_qr.rs
> @@ -545,7 +545,7 @@ fn add_segments(&mut self, segments: &[&Segment<'_>]) {
>           }
>           self.push(&mut offset, (MODE_STOP, 4));
>   
> -        let pad_offset = (offset + 7) / 8;
> +        let pad_offset = offset.div_ceil(8);
>           for i in pad_offset..self.version.max_data() {
>               self.data[i] = PADDING[(i & 1) ^ (pad_offset & 1)];
>           }
> @@ -659,7 +659,7 @@ struct QrImage<'a> {
>   impl QrImage<'_> {
>       fn new<'a, 'b>(em: &'b EncodedMsg<'b>, qrdata: &'a mut [u8]) -> QrImage<'a> {
>           let width = em.version.width();
> -        let stride = (width + 7) / 8;
> +        let stride = width.div_ceil(8);
>           let data = qrdata;
>   
>           let mut qr_image = QrImage {
> 
> base-commit: d082ecbc71e9e0bf49883ee4afd435a77a5101b6

Re: [PATCH 1/2] drm/panic: use `div_ceil` to clean Clippy warning

[Jocelyn Falempe]

On 02/03/2025 00:16, Miguel Ojeda wrote:
> Starting with the upcoming Rust 1.86.0 (to be released 2025-04-03),
> Clippy warns:
> 
>      error: manually reimplementing `div_ceil`
>         --> drivers/gpu/drm/drm_panic_qr.rs:548:26
>          |
>      548 |         let pad_offset = (offset + 7) / 8;
>          |                          ^^^^^^^^^^^^^^^^ help: consider using `.div_ceil()`: `offset.div_ceil(8)`
>          |
>          = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#manual_div_ceil
> 
> And similarly for `stride`. Thus apply the suggestion to both.
> 
> The behavior (and thus codegen) is not exactly equivalent [1][2], since
> `div_ceil()` returns the right value for the values that currently
> would overflow.

I pushed both patches to drm-misc-fixes, with the "Cc" tag added.

Thanks a lot for your contributions.

-- 

Jocelyn
> 
> Link: https://github.com/rust-lang/rust-clippy/issues/14333 [1]
> Link: https://godbolt.org/z/dPq6nGnv3 [2]
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
> ---
>   drivers/gpu/drm/drm_panic_qr.rs | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_panic_qr.rs b/drivers/gpu/drm/drm_panic_qr.rs
> index bcf248f69252..8bb5e52d75cc 100644
> --- a/drivers/gpu/drm/drm_panic_qr.rs
> +++ b/drivers/gpu/drm/drm_panic_qr.rs
> @@ -545,7 +545,7 @@ fn add_segments(&mut self, segments: &[&Segment<'_>]) {
>           }
>           self.push(&mut offset, (MODE_STOP, 4));
>   
> -        let pad_offset = (offset + 7) / 8;
> +        let pad_offset = offset.div_ceil(8);
>           for i in pad_offset..self.version.max_data() {
>               self.data[i] = PADDING[(i & 1) ^ (pad_offset & 1)];
>           }
> @@ -659,7 +659,7 @@ struct QrImage<'a> {
>   impl QrImage<'_> {
>       fn new<'a, 'b>(em: &'b EncodedMsg<'b>, qrdata: &'a mut [u8]) -> QrImage<'a> {
>           let width = em.version.width();
> -        let stride = (width + 7) / 8;
> +        let stride = width.div_ceil(8);
>           let data = qrdata;
>   
>           let mut qr_image = QrImage {
> 
> base-commit: d082ecbc71e9e0bf49883ee4afd435a77a5101b6