dma-buf: improve dma_buf_show_fdinfo output

Improve the readability of /proc/<pid>/fdinfo output for DMA-BUF by
including file flags and ensuring consistent format specifiers for size
and other fields.

This patch also fixes incorrect format specifiers and removes references
to obsolete struct members (num_attachments and num_mappings) that no
longer exist in the DMA-BUF framework.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202510220802.svbgdYsJ-lkp@intel.com/
---
 drivers/dma-buf/dma-buf.c | 26 ++++++++++++--------------
 1 file changed, 12 insertions(+), 14 deletions(-)

diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index 1c0035601c4f..4541f8ec5d62 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -571,24 +571,22 @@ static long dma_buf_ioctl(struct file *file,
 	}
 }
 
-static void dma_buf_show_fdinfo(struct seq_file *s, struct file *f)
+static void dma_buf_show_fdinfo(struct seq_file *s, struct file *file)
 {
-    struct dma_buf *dmabuf = f->private_data;
+	struct dma_buf *dmabuf;
 
-    if (!dmabuf)
-        return;
+	dmabuf = file->private_data;
+	if (!dmabuf)
+		return;
 
-    seq_printf(s, "flags:\t%lu\n", f->f_flags);
-    seq_printf(s, "size:\t%llu\n", dmabuf->size);
-    seq_printf(s, "count:\t%ld\n", file_count(dmabuf->file) - 1);
-    seq_printf(s, "attachments:\t%d\n", atomic_read(&dmabuf->num_attachments));
-    seq_printf(s, "mappings:\t%d\n", atomic_read(&dmabuf->num_mappings));
-    seq_printf(s, "exp_name:\t%s\n", dmabuf->exp_name ? dmabuf->exp_name : "N/A");
+	seq_printf(s, "size:\t%zu\n", dmabuf->size);
+	seq_printf(s, "count:\t%ld\n", file_count(dmabuf->file) - 1);
+	seq_printf(s, "exp_name:\t%s\n", dmabuf->exp_name ? dmabuf->exp_name : "N/A");
 
-    spin_lock(&dmabuf->name_lock);
-    if (dmabuf->name)
-        seq_printf(s, "name:\t%s\n", dmabuf->name);
-    spin_unlock(&dmabuf->name_lock);
+	spin_lock(&dmabuf->name_lock);
+	if (dmabuf->name)
+		seq_printf(s, "name:\t%s\n", dmabuf->name);
+	spin_unlock(&dmabuf->name_lock);
 }
 
 
-- 
2.43.0


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> dma-buf: improve dma_buf_show_fdinfo output
…
> This patch also fixes incorrect …

See also:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.18-rc2#n94


> Closes: https://lore.kernel.org/oe-kbuild-all/202510220802.svbgdYsJ-lkp@intel.com/

Not yet.

Please use a more appropriate patch subject for the proposed adjustment
of the function “dma_buf_show_fdinfo”.
https://elixir.bootlin.com/linux/v6.18-rc2/source/drivers/dma-buf/dma-buf.c#L570-L582
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.18-rc2#n396


> ---
>  drivers/dma-buf/dma-buf.c | 26 ++++++++++++--------------
…

Some contributors would appreciate patch version descriptions.
https://lore.kernel.org/all/?q=%22This+looks+like+a+new+version+of+a+previously+submitted+patch%22
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.18-rc2#n310


…
> +++ b/drivers/dma-buf/dma-buf.c
> @@ -571,24 +571,22 @@ static long dma_buf_ioctl(struct file *file,
>  	}
>  }
>  
> -static void dma_buf_show_fdinfo(struct seq_file *s, struct file *f)
> +static void dma_buf_show_fdinfo(struct seq_file *s, struct file *file)
>  {
…
…
> -    seq_printf(s, "flags:\t%lu\n", f->f_flags);
> -    seq_printf(s, "size:\t%llu\n", dmabuf->size);

* Why does such a diff representation contain space characters instead of tab characters?

* Did you refer to a source code variant before the commit bcc071110aeacd28a87525a2442dd96eab145a3c
  ("dma-buf: add show_fdinfo handler") from 2019-06-14?


…
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> ::DISCLAIMER::
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> contents of this e-mail and any attachment(s) are confidential and
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Please avoid such unwanted information for communication by the means of public mailing lists.
https://subspace.kernel.org/etiquette.html#do-not-include-confidentiality-disclaimers

Regards,
Markus

On Wed, 22 Oct 2025, Biancaa Ramesh <biancaa2210329@ssn.edu.in> wrote:
> -- 
> ::DISCLAIMER::
> 
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There are some obvious issues in the patch itself, but please do figure
out how to send patches and generally list email without disclaimers
like this first. Or use the b4 web submission endpoint [1].

BR,
Jani.


[1] https://b4.docs.kernel.org/en/latest/contributor/send.html

-- 
Jani Nikula, Intel