xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

[PATCH] mutex subsystem, semaphore to mutex: VFS, ->i_sem

Browse Source 
This patch converts the inode semaphore to a mutex. I have tested it on
XFS and compiled as much as one can consider on an ia64. Anyway your
luck with it might be different.

Modified-by: Ingo Molnar <mingo@elte.hu>

(finished the conversion)

Signed-off-by: Jes Sorensen <jes@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Jes Sorensen
2006-01-09 15:59:24 -08:00
committed by Ingo Molnar
parent 794ee1baee
commit 1b1dcc1b57
113 changed files with 563 additions and 573 deletions
Download Patch File Download Diff File Expand all files Collapse all files

22
fs/devfs/base.c
View File

@@ -2162,27 +2162,27 @@ static int devfs_d_revalidate_wait(struct dentry *dentry, struct nameidata *nd)
*
* make sure that
* d_instantiate always runs under lock
* we release i_sem lock before going to sleep
* we release i_mutex lock before going to sleep
*
* unfortunately sometimes d_revalidate is called with
* and sometimes without i_sem lock held. The following checks
* and sometimes without i_mutex lock held. The following checks
* attempt to deduce when we need to add (and drop resp.) lock
* here. This relies on current (2.6.2) calling coventions:
*
* lookup_hash is always run under i_sem and is passing NULL
* lookup_hash is always run under i_mutex and is passing NULL
* as nd
*
* open(...,O_CREATE,...) calls _lookup_hash under i_sem
* open(...,O_CREATE,...) calls _lookup_hash under i_mutex
* and sets flags to LOOKUP_OPEN|LOOKUP_CREATE
*
* all other invocations of ->d_revalidate seem to happen
* outside of i_sem
* outside of i_mutex
*/
need_lock = nd &&
(!(nd->flags & LOOKUP_CREATE) || (nd->flags & LOOKUP_PARENT));
if (need_lock)
down(&dir->i_sem);
mutex_lock(&dir->i_mutex);
if (is_devfsd_or_child(fs_info)) {
devfs_handle_t de = lookup_info->de;
@@ -2221,9 +2221,9 @@ static int devfs_d_revalidate_wait(struct dentry *dentry, struct nameidata *nd)
add_wait_queue(&lookup_info->wait_queue, &wait);
read_unlock(&parent->u.dir.lock);
/* at this point it is always (hopefully) locked */
up(&dir->i_sem);
mutex_unlock(&dir->i_mutex);
schedule();
down(&dir->i_sem);
mutex_lock(&dir->i_mutex);
/*
* This does not need nor should remove wait from wait_queue.
* Wait queue head is never reused - nothing is ever added to it
@@ -2238,7 +2238,7 @@ static int devfs_d_revalidate_wait(struct dentry *dentry, struct nameidata *nd)
out:
if (need_lock)
up(&dir->i_sem);
mutex_unlock(&dir->i_mutex);
return 1;
} /* End Function devfs_d_revalidate_wait */
@@ -2284,9 +2284,9 @@ static struct dentry *devfs_lookup(struct inode *dir, struct dentry *dentry,
/* Unlock directory semaphore, which will release any waiters. They
will get the hashed dentry, and may be forced to wait for
revalidation */
up(&dir->i_sem);
mutex_unlock(&dir->i_mutex);
wait_for_devfsd_finished(fs_info); /* If I'm not devfsd, must wait */
down(&dir->i_sem); /* Grab it again because them's the rules */
mutex_lock(&dir->i_mutex); /* Grab it again because them's the rules */
de = lookup_info.de;
/* If someone else has been so kind as to make the inode, we go home
early */