The following commit has been merged into the perf/core branch of tip:
Commit-ID: 244b28f87ba48daaed81bbfe5af079e320c1e093
Gitweb: https://git.kernel.org/tip/244b28f87ba48daaed81bbfe5af079e320c1e093
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Mon, 04 Nov 2024 14:39:27 +01:00
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Sat, 01 Mar 2025 20:32:30 +01:00
perf/core: Lift event->mmap_mutex in perf_mmap()
This puts 'all' of perf_mmap() under single event->mmap_mutex.
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20241104135519.582252957@xxxxxxxxxxxxx
---
kernel/events/core.c | 20 ++++++++------------
1 file changed, 8 insertions(+), 12 deletions(-)
diff --git a/kernel/events/core.c b/kernel/events/core.c
index ca4c124..773875a 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -6680,7 +6680,7 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma)
unsigned long vma_size;
unsigned long nr_pages;
long user_extra = 0, extra = 0;
- int ret = 0, flags = 0;
+ int ret, flags = 0;
/*
* Don't allow mmap() of inherited per-task counters. This would
@@ -6708,6 +6708,9 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma)
user_extra = nr_pages;
+ mutex_lock(&event->mmap_mutex);
+ ret = -EINVAL;
+
if (vma->vm_pgoff == 0) {
nr_pages -= 1;
@@ -6716,16 +6719,13 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma)
* can do bitmasks instead of modulo.
*/
if (nr_pages != 0 && !is_power_of_2(nr_pages))
- return -EINVAL;
+ goto unlock;
WARN_ON_ONCE(event->ctx->parent_ctx);
- mutex_lock(&event->mmap_mutex);
if (event->rb) {
- if (data_page_nr(event->rb) != nr_pages) {
- ret = -EINVAL;
+ if (data_page_nr(event->rb) != nr_pages)
goto unlock;
- }
if (atomic_inc_not_zero(&event->rb->mmap_count)) {
/*
@@ -6754,12 +6754,6 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma)
*/
u64 aux_offset, aux_size;
- if (!event->rb)
- return -EINVAL;
-
- mutex_lock(&event->mmap_mutex);
- ret = -EINVAL;
-
rb = event->rb;
if (!rb)
goto aux_unlock;
@@ -6869,6 +6863,8 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma)
rb->aux_mmap_locked = extra;
}
+ ret = 0;
+
unlock:
if (!ret) {
atomic_long_add(user_extra, &user->locked_vm);
|