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base: genlock: Remove genlock_release_lock and associated ioctl

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Allowing a lock to be asynchronously released while a handle
was still active turned out to be too dangerous to use in a
multi-threaded environment and it served no pratical
purpose anyway.  Handles now hold an attached lock until they
are destroyed.

CRs-fixed: 333141
Change-Id: Ic0dedbad8050ff01927ddb165c65a939bf297c10
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
This commit is contained in:
Jordan Crouse
2012-01-25 14:40:51 -07:00
parent a73ed09742
commit 4df70a254d
3 changed files with 14 additions and 18 deletions
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11
Documentation/genlock.txt
View File

@@ -82,15 +82,13 @@ descriptor.
Release a handle.
* struct genlock * genlock_create_lock(struct genlock_handle *)
Create a new lock and attach it to the handle.
Create a new lock and attach it to the handle. Once a lock is attached to a
handle it stays attached until the handle is destroyed.
* struct genlock * genlock_attach_lock(struct genlock_handle *handle, int fd)
Given a valid file descriptor, get the lock associated with it and attach it to
the handle.
* void genlock_release_lock(struct genlock_handle *)
Release a lock attached to a handle.
* int genlock_lock(struct genlock_handle *, int op, int flags, u32 timeout)
Lock or unlock the lock attached to the handle. A zero timeout value will
be treated just like if the GENOCK_NOBLOCK flag is passed; if the lock
@@ -155,7 +153,4 @@ passed in genlock_lock.timeout. Returns 0 when the lock has been released,
-EINVAL if a zero timeout is passed, or -ETIMEDOUT if the timeout expires.
* GENLOCK_IOC_RELEASE
Use this to release an existing lock. This is useful if you wish to attach a
different lock to the same handle. You do not need to call this under normal
circumstances; when the handle is closed the reference to the lock is released.
No data is passed from the user for this ioctl.
This ioctl has been deprecated. Do not use.

17
drivers/base/genlock.c
View File

@@ -496,12 +496,7 @@ done:
return ret;
}
/**
* genlock_release_lock - Release a lock attached to a handle
* @handle - Pointer to the handle holding the lock
*/
void genlock_release_lock(struct genlock_handle *handle)
static void genlock_release_lock(struct genlock_handle *handle)
{
unsigned long flags;
@@ -522,7 +517,6 @@ void genlock_release_lock(struct genlock_handle *handle)
handle->lock = NULL;
handle->active = 0;
}
EXPORT_SYMBOL(genlock_release_lock);
/*
* Release function called when all references to a handle are released
@@ -671,8 +665,13 @@ static long genlock_dev_ioctl(struct file *filep, unsigned int cmd,
return genlock_wait(handle, param.timeout);
}
case GENLOCK_IOC_RELEASE: {
genlock_release_lock(handle);
return 0;
/*
* Return error - this ioctl has been deprecated.
* Locks should only be released when the handle is
* destroyed
*/
GENLOCK_LOG_ERR("Deprecated RELEASE ioctl called\n");
return -EINVAL;
}
default:
GENLOCK_LOG_ERR("Invalid ioctl\n");

4
include/linux/genlock.h
View File

@@ -12,7 +12,7 @@ void genlock_put_handle(struct genlock_handle *handle);
struct genlock *genlock_create_lock(struct genlock_handle *);
struct genlock *genlock_attach_lock(struct genlock_handle *, int fd);
int genlock_wait(struct genlock_handle *handle, u32 timeout);
void genlock_release_lock(struct genlock_handle *);
/* genlock_release_lock was deprecated */
int genlock_lock(struct genlock_handle *handle, int op, int flags,
u32 timeout);
#endif
@@ -39,6 +39,8 @@ struct genlock_lock {
struct genlock_lock)
#define GENLOCK_IOC_LOCK _IOW(GENLOCK_IOC_MAGIC, 3, \
struct genlock_lock)
/* Deprecated */
#define GENLOCK_IOC_RELEASE _IO(GENLOCK_IOC_MAGIC, 4)
#define GENLOCK_IOC_WAIT _IOW(GENLOCK_IOC_MAGIC, 5, \
struct genlock_lock)