Messages in this thread Patch in this message | | | From | Frederic Weisbecker <> | Subject | [PATCH v2] generic_nvram: Turn nvram_ioctl into an unlocked ioctl | Date | Mon, 12 Oct 2009 00:39:02 +0200 |
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nvram_ioctl is a bkl locked ioctl, but it can be an unlocked ioctl.
- part is provided by the user - offset is provided by pmac_get_partition() which is safe as it only touches nvram_partitions, an array inistialized on __init time and read-only the rest of the time. - nvram_sync() only relies on core99_nvram_sync() which checks is_core_99, nvram_data, nvram_image. Those are variables initialized on __init time only and their direct values are not touched further. The rest modifies the nvram image header, protected by nv_lock already.
So it's safe to call nvram_ioctl without the big kernel lock held.
v2: Fix nvram_ioctl to fit unlocked_ioctl signature.
Reported-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: John Kacur <jkacur@redhat.com> Cc: Sven-Thorsten Dietrich <sven@thebigcorporation.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Alessio Igor Bogani <abogani@texware.it> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> --- drivers/char/generic_nvram.c | 13 ++++++------- 1 files changed, 6 insertions(+), 7 deletions(-)
diff --git a/drivers/char/generic_nvram.c b/drivers/char/generic_nvram.c index c49200e..866d04d 100644 --- a/drivers/char/generic_nvram.c +++ b/drivers/char/generic_nvram.c @@ -85,8 +85,7 @@ static ssize_t write_nvram(struct file *file, const char __user *buf, return p - buf; } -static int nvram_ioctl(struct inode *inode, struct file *file, - unsigned int cmd, unsigned long arg) +static int nvram_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { switch(cmd) { #ifdef CONFIG_PPC_PMAC @@ -118,11 +117,11 @@ static int nvram_ioctl(struct inode *inode, struct file *file, } const struct file_operations nvram_fops = { - .owner = THIS_MODULE, - .llseek = nvram_llseek, - .read = read_nvram, - .write = write_nvram, - .ioctl = nvram_ioctl, + .owner = THIS_MODULE, + .llseek = nvram_llseek, + .read = read_nvram, + .write = write_nvram, + .unlocked_ioctl = nvram_ioctl, }; static struct miscdevice nvram_dev = { -- 1.6.2.3
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