[PATCH v2] dma-buf: heaps: use max3() in dma_heap_ioctl

[PATCH v2] dma-buf: heaps: use max3() in dma_heap_ioctl

[Thorsten Blum]

Replace two nested max() calls with a single max3() in dma_heap_ioctl().

Reviewed-by: T.J. Mercier <tjmercier@google.com>
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
---
Changes in v2:
- Include minmax.h as suggested by T.J. Mercier
- v1: https://lore.kernel.org/lkml/20260427172519.417333-3-thorsten.blum@linux.dev/
---
 drivers/dma-buf/dma-heap.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/dma-buf/dma-heap.c b/drivers/dma-buf/dma-heap.c
index ac5f8685a649..d49188893608 100644
--- a/drivers/dma-buf/dma-heap.c
+++ b/drivers/dma-buf/dma-heap.c
@@ -13,6 +13,7 @@
 #include <linux/err.h>
 #include <linux/export.h>
 #include <linux/list.h>
+#include <linux/minmax.h>
 #include <linux/nospec.h>
 #include <linux/syscalls.h>
 #include <linux/uaccess.h>
@@ -153,7 +154,7 @@ static long dma_heap_ioctl(struct file *file, unsigned int ucmd,
 		in_size = 0;
 	if ((ucmd & kcmd & IOC_OUT) == 0)
 		out_size = 0;
-	ksize = max(max(in_size, out_size), drv_size);
+	ksize = max3(in_size, out_size, drv_size);
 
 	/* If necessary, allocate buffer for ioctl argument */
 	if (ksize > sizeof(stack_kdata)) {

Claude review: dma-buf: heaps: use max3() in dma_heap_ioctl

[Claude Code Review Bot]

Overall Series Review

Subject: dma-buf: heaps: use max3() in dma_heap_ioctl
Author: Thorsten Blum <thorsten.blum@linux.dev>
Patches: 1
Reviewed: 2026-04-28T13:58:20.743919

---

This is a single, trivial cleanup patch that replaces nested `max(max(a, b), c)` with the dedicated `max3(a, b, c)` macro. The change is correct, improves readability marginally, and has no functional impact. It already carries a Reviewed-by tag from a dma-buf maintainer (T.J. Mercier). No concerns.

---
Generated by Claude Code Patch Reviewer

Claude review: dma-buf: heaps: use max3() in dma_heap_ioctl

[Claude Code Review Bot]

Patch Review

**Status: Looks good**

The patch does two things:

1. Adds `#include <linux/minmax.h>` — correct, since `max3()` is defined there and was not previously included directly. Alphabetical ordering of the include is maintained.

2. Replaces:
   ```c
   ksize = max(max(in_size, out_size), drv_size);
   ```
   with:
   ```c
   ksize = max3(in_size, out_size, drv_size);
   ```

This is a straightforward substitution. `max3()` in `include/linux/minmax.h` (line 152) is defined via `__careful_op3(max, ...)` which performs the same type-safe three-way max. The semantics are identical.

**Minor observations:**
- The v1→v2 changelog is clear: v1 was missing the explicit `minmax.h` include, and T.J. Mercier caught it. Good iteration.
- `max()` is likely already transitively available (via `kernel.h` or similar), but adding the explicit `minmax.h` include for `max3()` is the right practice — it avoids relying on transitive includes that could break in future header cleanups.

No issues found. The patch is correct and ready to merge.

---
Generated by Claude Code Patch Reviewer

Claude review: dma-buf: heaps: use max3() in dma_heap_ioctl

[Claude Code Review Bot]

Overall Series Review

Subject: dma-buf: heaps: use max3() in dma_heap_ioctl
Author: Thorsten Blum <thorsten.blum@linux.dev>
Patches: 2
Reviewed: 2026-04-28T14:15:58.686759

---

This is a single-patch trivial cleanup that replaces nested `max(max(a, b), c)` with the equivalent `max3(a, b, c)` macro. The change is correct, improves readability marginally, and has no functional impact. The `max3` macro is already available through the existing include chain (via `linux/minmax.h`, included transitively through `linux/device.h` -> `linux/kernel.h`).

**Verdict:** Harmless cleanup. No concerns.

---
Generated by Claude Code Patch Reviewer

Claude review: dma-buf: heaps: use max3() in dma_heap_ioctl

[Claude Code Review Bot]

Patch Review

**Status:** Looks good.

The change replaces:
```c
ksize = max(max(in_size, out_size), drv_size);
```
with:
```c
ksize = max3(in_size, out_size, drv_size);
```

This is a straightforward substitution. `max3()` is defined in `include/linux/minmax.h:152` and is available in this compilation unit through the existing include chain. The three arguments (`in_size`, `out_size`, `drv_size`) are all the same type (`unsigned int` derived from the ioctl size encoding), so there are no type-promotion surprises.

The commit message is accurate and concise. The Signed-off-by is present.

**Reviewed-by worthy:** Yes, no issues found.

---
Generated by Claude Code Patch Reviewer