In order to remove Big Kernel Lock usages from the DVB subsystem,
we need to
- provide .llseek file operations that do not grab the BKL (unlike
fs/read_write.c::default_llseek) or mark files as not seekable,
- provide .unlocked_ioctl file operations.
Add two dvb_generic_ file operations for file interfaces which are not
seekable and, respectively, do not require the BKL in their ioctl
handlers.
Use them in one driver of which I am sure of that these are applicable.
(Affected code paths were not runtime-tested since I don't have a CAM.)
Notes:
- In order to maximize code reuse and minimize API churn, I pass a
dummy NULL struct inode * through dvb_usercopy() to
dvbdev->kernel_ioctl(). Very ugly; it may be better to convert
everything from .ioctl to .unlocked_ioctl in one go and remove the
inode pointer argument everywhere.
- I suspect that actually all dvb_generic_open() users really want
nonseekable_open --- then we should simply change dvb_generic_open()
instead of adding dvb_generic_nonseekable_open() --- but I haven't
checked other users of dvb_generic_open whether they require
.llssek mehods other than fs/read_write.c::no_llseek.
Signed-off-by: Stefan Richter <stefanr@xxxxxxxxxxxxxxxxx>
---
This patch is motivated by Arnd's
"bkl removal: make unlocked_ioctl mandatory"
http://git.kernel.org/?p=linux/kernel/git/arnd/playground.git;a=blobdiff;f=drivers/media/dvb/firewire/firedtv-ci.c;h=7ab89035c101240a860d6c72bf8541a0fdf3aed9;hp=853e04b7cb361d45257f80dcafdcf121cd340c63;hb=05e7753338045e9ee3950b2da032c5e5774efa90;hpb=03165e1d096afb4b1d9cfccdad66eed038121cec
"BKL removal: mark remaining users as 'depends on BKL'"
http://git.kernel.org/?p=linux/kernel/git/arnd/playground.git;a=blobdiff;f=drivers/media/dvb/firewire/Kconfig;h=ba8938e26414c8c82c41677f87c1361ed8fcebd0;hp=4afa29256df110d3383b6b469762cefbb46436b6;hb=abb83d8fe5f8dcc8fca09bd9117429f73e1417e0;hpb=33c014b118f45516113d4b6823e40ea6f834dc6a
drivers/media/dvb/dvb-core/dvbdev.c | 20 ++++++++++++++++++++
drivers/media/dvb/dvb-core/dvbdev.h | 11 +++++++----
drivers/media/dvb/firewire/firedtv-ci.c | 4 ++--
3 files changed, 29 insertions(+), 6 deletions(-)
Index: b/drivers/media/dvb/dvb-core/dvbdev.c
===================================================================
--- a/drivers/media/dvb/dvb-core/dvbdev.c
+++ b/drivers/media/dvb/dvb-core/dvbdev.c
@@ -135,6 +135,18 @@ int dvb_generic_open(struct inode *inode
EXPORT_SYMBOL(dvb_generic_open);
+int dvb_generic_nonseekable_open(struct inode *inode, struct file *file)
+{
+ int retval = dvb_generic_open(inode, file);
+
+ if (retval == 0)
+ retval = nonseekable_open(inode, file);
+
+ return retval;
+}
+EXPORT_SYMBOL(dvb_generic_nonseekable_open);
+
+
int dvb_generic_release(struct inode *inode, struct file *file)
{
struct dvb_device *dvbdev = file->private_data;
@@ -170,6 +182,14 @@ int dvb_generic_ioctl(struct inode *inod
EXPORT_SYMBOL(dvb_generic_ioctl);
+long dvb_generic_unlocked_ioctl(struct file *file,
+ unsigned int cmd, unsigned long arg)
+{
+ return dvb_generic_ioctl(NULL, file, cmd, arg);
+}
+EXPORT_SYMBOL(dvb_generic_unlocked_ioctl);
+
+
static int dvbdev_get_free_id (struct dvb_adapter *adap, int type)
{
u32 id = 0;
Index: b/drivers/media/dvb/dvb-core/dvbdev.h
===================================================================
--- a/drivers/media/dvb/dvb-core/dvbdev.h
+++ b/drivers/media/dvb/dvb-core/dvbdev.h
@@ -136,10 +136,13 @@ extern int dvb_register_device (struct d
extern void dvb_unregister_device (struct dvb_device *dvbdev);
-extern int dvb_generic_open (struct inode *inode, struct file *file);
-extern int dvb_generic_release (struct inode *inode, struct file *file);
-extern int dvb_generic_ioctl (struct inode *inode, struct file *file,
- unsigned int cmd, unsigned long arg);
+extern int dvb_generic_open(struct inode *inode, struct file *file);
+extern int dvb_generic_nonseekable_open(struct inode *inode, struct file *file);
+extern int dvb_generic_release(struct inode *inode, struct file *file);
+extern int dvb_generic_ioctl(struct inode *inode, struct file *file,
+ unsigned int cmd, unsigned long arg);
+extern long dvb_generic_unlocked_ioctl(struct file *file,
+ unsigned int cmd, unsigned long arg);
/* we don't mess with video_usercopy() any more,
we simply define out own dvb_usercopy(), which will hopefully become
Index: b/drivers/media/dvb/firewire/firedtv-ci.c
===================================================================
--- a/drivers/media/dvb/firewire/firedtv-ci.c
+++ b/drivers/media/dvb/firewire/firedtv-ci.c
@@ -217,8 +217,8 @@ static unsigned int fdtv_ca_io_poll(stru
static const struct file_operations fdtv_ca_fops = {
.owner = THIS_MODULE,
- .ioctl = dvb_generic_ioctl,
- .open = dvb_generic_open,
+ .unlocked_ioctl = dvb_generic_unlocked_ioctl,
+ .open = dvb_generic_nonseekable_open,
.release = dvb_generic_release,
.poll = fdtv_ca_io_poll,
};
--
Stefan Richter
-=====-==-=- --== ==-==
http://arcgraph.de/sr/
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