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authorArnd Bergmann <arnd@arndb.de>2010-09-18 15:09:31 +0200
committerArnd Bergmann <arnd@arndb.de>2010-10-05 11:02:04 +0200
commitb89f432133851a01c0d28822f11cbdcc15781a75 (patch)
treea3e9ba638a9b746985148f4525335d360ec7da56 /fs/nfsd
parent2e54eb96e2c801f33d95b5dade15212ac4d6c4a5 (diff)
fs/locks.c: prepare for BKL removal
This prepares the removal of the big kernel lock from the file locking code. We still use the BKL as long as fs/lockd uses it and ceph might sleep, but we can flip the definition to a private spinlock as soon as that's done. All users outside of fs/lockd get converted to use lock_flocks() instead of lock_kernel() where appropriate. Based on an earlier patch to use a spinlock from Matthew Wilcox, who has attempted this a few times before, the earliest patch from over 10 years ago turned it into a semaphore, which ended up being slower than the BKL and was subsequently reverted. Someone should do some serious performance testing when this becomes a spinlock, since this has caused problems before. Using a spinlock should be at least as good as the BKL in theory, but who knows... Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Matthew Wilcox <willy@linux.intel.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Cc: "J. Bruce Fields" <bfields@fieldses.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Miklos Szeredi <mszeredi@suse.cz> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: John Kacur <jkacur@redhat.com> Cc: Sage Weil <sage@newdream.net> Cc: linux-kernel@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org
Diffstat (limited to 'fs/nfsd')
-rw-r--r--fs/nfsd/nfs4state.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index cf0d2ffb3c84..a7292fcf7718 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -33,7 +33,7 @@
*/
#include <linux/file.h>
-#include <linux/smp_lock.h>
+#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/namei.h>
#include <linux/swap.h>
@@ -3895,7 +3895,7 @@ check_for_locks(struct nfs4_file *filp, struct nfs4_stateowner *lowner)
struct inode *inode = filp->fi_inode;
int status = 0;
- lock_kernel();
+ lock_flocks();
for (flpp = &inode->i_flock; *flpp != NULL; flpp = &(*flpp)->fl_next) {
if ((*flpp)->fl_owner == (fl_owner_t)lowner) {
status = 1;
@@ -3903,7 +3903,7 @@ check_for_locks(struct nfs4_file *filp, struct nfs4_stateowner *lowner)
}
}
out:
- unlock_kernel();
+ unlock_flocks();
return status;
}