[PATCH] mutex subsystem, semaphore to mutex: VFS, ->i_sem
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>
diff --git a/fs/direct-io.c b/fs/direct-io.c
index 3931e7f..30dbbd1 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -56,7 +56,7 @@
* lock_type is DIO_LOCKING for regular files on direct-IO-naive filesystems.
* This determines whether we need to do the fancy locking which prevents
* direct-IO from being able to read uninitialised disk blocks. If its zero
- * (blockdev) this locking is not done, and if it is DIO_OWN_LOCKING i_sem is
+ * (blockdev) this locking is not done, and if it is DIO_OWN_LOCKING i_mutex is
* not held for the entire direct write (taken briefly, initially, during a
* direct read though, but its never held for the duration of a direct-IO).
*/
@@ -930,7 +930,7 @@
}
/*
- * Releases both i_sem and i_alloc_sem
+ * Releases both i_mutex and i_alloc_sem
*/
static ssize_t
direct_io_worker(int rw, struct kiocb *iocb, struct inode *inode,
@@ -1062,11 +1062,11 @@
/*
* All block lookups have been performed. For READ requests
- * we can let i_sem go now that its achieved its purpose
+ * we can let i_mutex go now that its achieved its purpose
* of protecting us from looking up uninitialized blocks.
*/
if ((rw == READ) && (dio->lock_type == DIO_LOCKING))
- up(&dio->inode->i_sem);
+ mutex_unlock(&dio->inode->i_mutex);
/*
* OK, all BIOs are submitted, so we can decrement bio_count to truly
@@ -1145,18 +1145,18 @@
* The locking rules are governed by the dio_lock_type parameter.
*
* DIO_NO_LOCKING (no locking, for raw block device access)
- * For writes, i_sem is not held on entry; it is never taken.
+ * For writes, i_mutex is not held on entry; it is never taken.
*
* DIO_LOCKING (simple locking for regular files)
- * For writes we are called under i_sem and return with i_sem held, even though
+ * For writes we are called under i_mutex and return with i_mutex held, even though
* it is internally dropped.
- * For reads, i_sem is not held on entry, but it is taken and dropped before
+ * For reads, i_mutex is not held on entry, but it is taken and dropped before
* returning.
*
* DIO_OWN_LOCKING (filesystem provides synchronisation and handling of
* uninitialised data, allowing parallel direct readers and writers)
- * For writes we are called without i_sem, return without it, never touch it.
- * For reads, i_sem is held on entry and will be released before returning.
+ * For writes we are called without i_mutex, return without it, never touch it.
+ * For reads, i_mutex is held on entry and will be released before returning.
*
* Additional i_alloc_sem locking requirements described inline below.
*/
@@ -1214,11 +1214,11 @@
* For block device access DIO_NO_LOCKING is used,
* neither readers nor writers do any locking at all
* For regular files using DIO_LOCKING,
- * readers need to grab i_sem and i_alloc_sem
- * writers need to grab i_alloc_sem only (i_sem is already held)
+ * readers need to grab i_mutex and i_alloc_sem
+ * writers need to grab i_alloc_sem only (i_mutex is already held)
* For regular files using DIO_OWN_LOCKING,
* neither readers nor writers take any locks here
- * (i_sem is already held and release for writers here)
+ * (i_mutex is already held and release for writers here)
*/
dio->lock_type = dio_lock_type;
if (dio_lock_type != DIO_NO_LOCKING) {
@@ -1228,7 +1228,7 @@
mapping = iocb->ki_filp->f_mapping;
if (dio_lock_type != DIO_OWN_LOCKING) {
- down(&inode->i_sem);
+ mutex_lock(&inode->i_mutex);
reader_with_isem = 1;
}
@@ -1240,7 +1240,7 @@
}
if (dio_lock_type == DIO_OWN_LOCKING) {
- up(&inode->i_sem);
+ mutex_unlock(&inode->i_mutex);
reader_with_isem = 0;
}
}
@@ -1266,7 +1266,7 @@
out:
if (reader_with_isem)
- up(&inode->i_sem);
+ mutex_unlock(&inode->i_mutex);
if (rw & WRITE)
current->flags &= ~PF_SYNCWRITE;
return retval;