The data structures it's protecting are all contained by the
cache_detail, so having a global lock is unnecessary and potentially
a performance limitation.
Signed-off-by: Greg Banks <gnb@xxxxxxx>
---
include/linux/sunrpc/cache.h | 2 +
net/sunrpc/cache.c | 48 ++++++++++++++++----------------
2 files changed, 26 insertions(+), 24 deletions(-)
Index: bfields/include/linux/sunrpc/cache.h
===================================================================
--- bfields.orig/include/linux/sunrpc/cache.h
+++ bfields/include/linux/sunrpc/cache.h
@@ -16,6 +16,7 @@
#include <linux/slab.h>
#include <asm/atomic.h>
#include <linux/proc_fs.h>
+#include <linux/spinlock.h>
/*
* Each cache requires:
@@ -95,6 +96,7 @@ struct cache_detail {
int entries;
/* fields for communication over channel */
+ spinlock_t queue_lock;
struct list_head queue;
struct proc_dir_entry *proc_ent;
struct proc_dir_entry *flush_ent, *channel_ent, *content_ent;
Index: bfields/net/sunrpc/cache.c
===================================================================
--- bfields.orig/net/sunrpc/cache.c
+++ bfields/net/sunrpc/cache.c
@@ -359,6 +359,7 @@ int cache_register(struct cache_detail *
if (ret)
return ret;
rwlock_init(&cd->hash_lock);
+ spin_lock_init(&cd->queue_lock);
INIT_LIST_HEAD(&cd->queue);
spin_lock(&cache_list_lock);
cd->nextcheck = 0;
@@ -672,7 +673,6 @@ void cache_clean_deferred(void *owner)
*
*/
-static DEFINE_SPINLOCK(queue_lock);
static DEFINE_MUTEX(queue_io_mutex);
struct cache_queue {
@@ -705,7 +705,7 @@ cache_read(struct file *filp, char __use
mutex_lock(&queue_io_mutex); /* protect against multiple concurrent
* readers on this file */
again:
- spin_lock(&queue_lock);
+ spin_lock(&cd->queue_lock);
/* need to find next request */
while (rp->q.list.next != &cd->queue &&
list_entry(rp->q.list.next, struct cache_queue, list)
@@ -714,7 +714,7 @@ cache_read(struct file *filp, char __use
list_move(&rp->q.list, next);
}
if (rp->q.list.next == &cd->queue) {
- spin_unlock(&queue_lock);
+ spin_unlock(&cd->queue_lock);
mutex_unlock(&queue_io_mutex);
BUG_ON(rp->offset);
return 0;
@@ -723,13 +723,13 @@ cache_read(struct file *filp, char __use
BUG_ON(rq->q.reader);
if (rp->offset == 0)
rq->readers++;
- spin_unlock(&queue_lock);
+ spin_unlock(&cd->queue_lock);
if (rp->offset == 0 && !test_bit(CACHE_PENDING, &rq->item->flags)) {
err = -EAGAIN;
- spin_lock(&queue_lock);
+ spin_lock(&cd->queue_lock);
list_move(&rp->q.list, &rq->q.list);
- spin_unlock(&queue_lock);
+ spin_unlock(&cd->queue_lock);
} else {
if (rp->offset + count > rq->len)
count = rq->len - rp->offset;
@@ -739,26 +739,26 @@ cache_read(struct file *filp, char __use
rp->offset += count;
if (rp->offset >= rq->len) {
rp->offset = 0;
- spin_lock(&queue_lock);
+ spin_lock(&cd->queue_lock);
list_move(&rp->q.list, &rq->q.list);
- spin_unlock(&queue_lock);
+ spin_unlock(&cd->queue_lock);
}
err = 0;
}
out:
if (rp->offset == 0) {
/* need to release rq */
- spin_lock(&queue_lock);
+ spin_lock(&cd->queue_lock);
rq->readers--;
if (rq->readers == 0 &&
!test_bit(CACHE_PENDING, &rq->item->flags)) {
list_del(&rq->q.list);
- spin_unlock(&queue_lock);
+ spin_unlock(&cd->queue_lock);
cache_put(rq->item, cd);
kfree(rq->buf);
kfree(rq);
} else
- spin_unlock(&queue_lock);
+ spin_unlock(&cd->queue_lock);
}
if (err == -EAGAIN)
goto again;
@@ -814,7 +814,7 @@ cache_poll(struct file *filp, poll_table
if (!rp)
return mask;
- spin_lock(&queue_lock);
+ spin_lock(&cd->queue_lock);
for (cq= &rp->q; &cq->list != &cd->queue;
cq = list_entry(cq->list.next, struct cache_queue, list))
@@ -822,7 +822,7 @@ cache_poll(struct file *filp, poll_table
mask |= POLLIN | POLLRDNORM;
break;
}
- spin_unlock(&queue_lock);
+ spin_unlock(&cd->queue_lock);
return mask;
}
@@ -838,7 +838,7 @@ cache_ioctl(struct inode *ino, struct fi
if (cmd != FIONREAD || !rp)
return -EINVAL;
- spin_lock(&queue_lock);
+ spin_lock(&cd->queue_lock);
/* only find the length remaining in current request,
* or the length of the next request
@@ -851,7 +851,7 @@ cache_ioctl(struct inode *ino, struct fi
len = rq->len - rp->offset;
break;
}
- spin_unlock(&queue_lock);
+ spin_unlock(&cd->queue_lock);
return put_user(len, (int __user *)arg);
}
@@ -871,9 +871,9 @@ cache_open(struct inode *inode, struct f
rp->offset = 0;
rp->q.reader = 1;
atomic_inc(&cd->readers);
- spin_lock(&queue_lock);
+ spin_lock(&cd->queue_lock);
list_add(&rp->q.list, &cd->queue);
- spin_unlock(&queue_lock);
+ spin_unlock(&cd->queue_lock);
}
filp->private_data = rp;
return 0;
@@ -886,7 +886,7 @@ cache_release(struct inode *inode, struc
struct cache_detail *cd = PDE(inode)->data;
if (rp) {
- spin_lock(&queue_lock);
+ spin_lock(&cd->queue_lock);
if (rp->offset) {
struct cache_queue *cq;
for (cq= &rp->q; &cq->list != &cd->queue;
@@ -899,7 +899,7 @@ cache_release(struct inode *inode, struc
rp->offset = 0;
}
list_del(&rp->q.list);
- spin_unlock(&queue_lock);
+ spin_unlock(&cd->queue_lock);
filp->private_data = NULL;
kfree(rp);
@@ -927,7 +927,7 @@ static const struct file_operations cach
static void cache_remove_queued(struct cache_detail *cd, struct cache_head *h)
{
struct cache_queue *cq;
- spin_lock(&queue_lock);
+ spin_lock(&cd->queue_lock);
list_for_each_entry(cq, &cd->queue, list)
if (!cq->reader) {
struct cache_request *rq = container_of(cq, struct cache_request, q);
@@ -936,13 +936,13 @@ static void cache_remove_queued(struct c
if (rq->readers != 0)
continue;
list_del(&rq->q.list);
- spin_unlock(&queue_lock);
+ spin_unlock(&cd->queue_lock);
cache_put(rq->item, cd);
kfree(rq->buf);
kfree(rq);
return;
}
- spin_unlock(&queue_lock);
+ spin_unlock(&cd->queue_lock);
}
/*
@@ -1073,9 +1073,9 @@ static int cache_make_upcall(struct cach
rq->buf = buf;
rq->len = PAGE_SIZE - len;
rq->readers = 0;
- spin_lock(&queue_lock);
+ spin_lock(&cd->queue_lock);
list_add_tail(&rq->q.list, &cd->queue);
- spin_unlock(&queue_lock);
+ spin_unlock(&cd->queue_lock);
wake_up(&queue_wait);
return 0;
}
--
--
Greg Banks, P.Engineer, SGI Australian Software Group.
the brightly coloured sporks of revolution.
I don't speak for SGI.
--
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