On 09/09/25 5:58 PM, Markus Elfring wrote:

From: Markus Elfring elfring@users.sourceforge.net Date: Tue, 9 Sep 2025 14:20:06 +0200

Scope-based resource management became supported for some programming interfaces by contributions of Peter Zijlstra on 2023-05-26. See also the commit 54da6a0924311c7cf5015533991e44fb8eb12773 ("locking:

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

SHA ID here just needs first 12 digits not the entire string.

Introduce __cleanup() based infrastructure").

• Thus use the attribute “__free(kfree)”.

• Reduce the scopes for the local variables “buf” and “pglist”.

What is that required ?

• Omit four kfree() calls accordingly.

Right.

The commit message should be re-written with little more context from arm_trbe_alloc_buffer(), after describing the new scope-based resource management.

Signed-off-by: Markus Elfring elfring@users.sourceforge.net

drivers/hwtracing/coresight/coresight-trbe.c | 21 ++++++++------------ 1 file changed, 8 insertions(+), 13 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c index 8f9bbef71f23..1b0d58bf8613 100644 --- a/drivers/hwtracing/coresight/coresight-trbe.c +++ b/drivers/hwtracing/coresight/coresight-trbe.c @@ -733,8 +733,6 @@ static void *arm_trbe_alloc_buffer(struct coresight_device *csdev, struct perf_event *event, void **pages, int nr_pages, bool snapshot) {

• struct trbe_buf *buf;
• struct page **pglist; int i;

/* @@ -746,32 +744,29 @@ static void *arm_trbe_alloc_buffer(struct coresight_device *csdev, if (nr_pages < 2) return NULL;

• buf = kzalloc_node(sizeof(*buf), GFP_KERNEL, trbe_alloc_node(event));

• struct trbe_buf *buf __free(kfree) = kzalloc_node(sizeof(*buf),

• 					  GFP_KERNEL,
  

• 					  trbe_alloc_node(event));
  

  if (!buf) return NULL;

• pglist = kcalloc(nr_pages, sizeof(*pglist), GFP_KERNEL);
• if (!pglist) {

• kfree(buf);
  

• struct page **pglist __free(kfree) = kcalloc(nr_pages, sizeof(*pglist), GFP_KERNEL);
• if (!pglist) return NULL;

• }

for (i = 0; i < nr_pages; i++) pglist[i] = virt_to_page(pages[i]); buf->trbe_base = (unsigned long)vmap(pglist, nr_pages, VM_MAP, PAGE_KERNEL);

• if (!buf->trbe_base) {

• kfree(pglist);
  

• kfree(buf);
  

• if (!buf->trbe_base) return NULL;

• }

• buf->trbe_limit = buf->trbe_base + nr_pages * PAGE_SIZE; buf->trbe_write = buf->trbe_base; buf->snapshot = snapshot; buf->nr_pages = nr_pages; buf->pages = pages;

• kfree(pglist);
• return buf;

• return_ptr(buf);

} static void arm_trbe_free_buffer(void *config)

Seems like a good idea though. But please keep the local variable declaration in the current place which is bit cleaner and reduces code churn as well.

diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c index 7a226316c48f..7babba1a9afb 100644 --- a/drivers/hwtracing/coresight/coresight-trbe.c +++ b/drivers/hwtracing/coresight/coresight-trbe.c @@ -733,8 +733,8 @@ static void *arm_trbe_alloc_buffer(struct coresight_device *csdev, struct perf_event *event, void **pages, int nr_pages, bool snapshot) { - struct trbe_buf *buf; - struct page **pglist; + struct trbe_buf *buf __free(kfree); + struct page **pglist __free(kfree); int i;

/* @@ -751,27 +751,22 @@ static void *arm_trbe_alloc_buffer(struct coresight_device *csdev, return NULL;

pglist = kcalloc(nr_pages, sizeof(*pglist), GFP_KERNEL); - if (!pglist) { - kfree(buf); + if (!pglist) return NULL; - }

for (i = 0; i < nr_pages; i++) pglist[i] = virt_to_page(pages[i]);

buf->trbe_base = (unsigned long)vmap(pglist, nr_pages, VM_MAP, PAGE_KERNEL); - if (!buf->trbe_base) { - kfree(pglist); - kfree(buf); + if (!buf->trbe_base) return NULL; - } + buf->trbe_limit = buf->trbe_base + nr_pages * PAGE_SIZE; buf->trbe_write = buf->trbe_base; buf->snapshot = snapshot; buf->nr_pages = nr_pages; buf->pages = pages; - kfree(pglist); - return buf; + return_ptr(buf); }

static void arm_trbe_free_buffer(void *config)