Le 14/05/2026 à 05:57, Venkat a écrit :
Hi,
Gentle ping on this patch.
This removes the unused global nvram_mutex and relies on the
existing per-architecture synchronization, as suggested earlier.
I’ve re-tested the change, and everything continues to work as expected.
No issues observed in validation.
Please let me know if any further changes are needed.
Thanks,
Venkat
On 28 Apr 2026, at 11:45 AM, Venkat Rao Bagalkote <[email protected]>
wrote:
The global nvram_mutex in drivers/char/nvram.c is redundant and unused,
Redundant with what ?
It is _used_, at least in nvram_misc_ioctl()
and this triggers compiler warnings on some configurations.
All platform-specific nvram operations already provide their own internal
synchronization, meaning the wrapper-level mutex does not provide any
additional safety.
Indeed, this is what it is redundant with, I would say that first thing
in the message.
I think it would also be worth providing the history from Arnd from
here:
https://patchwork.ozlabs.org/project/linuxppc-dev/patch/[email protected]/#3667538
Remove the nvram_mutex definition along with all remaining lock/unlock
users across PPC32, x86, and m68k code paths, and rely entirely on the
per-architecture nvram implementations for locking.
Reviewed-by: Arnd Bergmann <[email protected]>
Suggested-by: Arnd Bergmann <[email protected]>
Tested-by: Tellakula Yeswanth Krishna <[email protected]>
Signed-off-by: Venkat Rao Bagalkote <[email protected]>
With the above changes, Reviewed-by: Christophe Leroy (CS GROUP)
<[email protected]>
---
Changes since v4:
- No code changes
- Resent after v7.1-rc1 as suggested by Arnd Bergmann
drivers/char/nvram.c | 16 +++-------------
1 file changed, 3 insertions(+), 13 deletions(-)
diff --git a/drivers/char/nvram.c b/drivers/char/nvram.c
index 9eff426a9286..e89cc1f1c89e 100644
--- a/drivers/char/nvram.c
+++ b/drivers/char/nvram.c
@@ -53,7 +53,6 @@
#include <asm/nvram.h>
#endif
-static DEFINE_MUTEX(nvram_mutex);
static DEFINE_SPINLOCK(nvram_state_lock);
static int nvram_open_cnt; /* #times opened */
static int nvram_open_mode; /* special open modes */
@@ -310,11 +309,8 @@ static long nvram_misc_ioctl(struct file *file, unsigned
int cmd,
break;
#ifdef CONFIG_PPC32
case IOC_NVRAM_SYNC:
- if (ppc_md.nvram_sync != NULL) {
- mutex_lock(&nvram_mutex);
+ if (ppc_md.nvram_sync)
ppc_md.nvram_sync();
- mutex_unlock(&nvram_mutex);
- }
ret = 0;
break;
#endif
@@ -324,11 +320,8 @@ static long nvram_misc_ioctl(struct file *file, unsigned
int cmd,
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
- if (arch_nvram_ops.initialize != NULL) {
- mutex_lock(&nvram_mutex);
+ if (arch_nvram_ops.initialize)
ret = arch_nvram_ops.initialize();
- mutex_unlock(&nvram_mutex);
- }
break;
case NVRAM_SETCKS:
/* just set checksum, contents unchanged (maybe useful after
@@ -336,11 +329,8 @@ static long nvram_misc_ioctl(struct file *file, unsigned
int cmd,
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
- if (arch_nvram_ops.set_checksum != NULL) {
- mutex_lock(&nvram_mutex);
+ if (arch_nvram_ops.set_checksum)
ret = arch_nvram_ops.set_checksum();
- mutex_unlock(&nvram_mutex);
- }
break;
#endif /* CONFIG_X86 || CONFIG_M68K */
}
--
2.45.2
