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Subject[PATCH] net/9p/client.c: fix misuse of spin_lock_irqsave for p9_client lock
Date
In p9_read_work(), we use spin_lock for client->lock, but misuse
spin_lock_irqsave for it in p9_fid_create(). As p9_client lock won't be
locked in irq context, so spin_lock is enough. And that will improve the
performance.

Signed-off-by: Jun Piao <piaojun@huawei.com>
---
net/9p/client.c | 17 +++++++----------
net/9p/trans_fd.c | 7 +++----
2 files changed, 10 insertions(+), 14 deletions(-)

diff --git a/net/9p/client.c b/net/9p/client.c
index 8bc8b3e..b05cbfc 100644
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -260,7 +260,6 @@ static struct p9_fcall *p9_fcall_alloc(int alloc_msize)
static struct p9_req_t *
p9_tag_alloc(struct p9_client *c, u16 tag, unsigned int max_size)
{
- unsigned long flags;
int row, col;
struct p9_req_t *req;
int alloc_msize = min(c->msize, max_size);
@@ -270,7 +269,7 @@ static struct p9_fcall *p9_fcall_alloc(int alloc_msize)
tag++;

if (tag >= c->max_tag) {
- spin_lock_irqsave(&c->lock, flags);
+ spin_lock(&c->lock);
/* check again since original check was outside of lock */
while (tag >= c->max_tag) {
row = (tag / P9_ROW_MAXTAG);
@@ -279,7 +278,7 @@ static struct p9_fcall *p9_fcall_alloc(int alloc_msize)

if (!c->reqs[row]) {
pr_err("Couldn't grow tag array\n");
- spin_unlock_irqrestore(&c->lock, flags);
+ spin_unlock(&c->lock);
return ERR_PTR(-ENOMEM);
}
for (col = 0; col < P9_ROW_MAXTAG; col++) {
@@ -288,7 +287,7 @@ static struct p9_fcall *p9_fcall_alloc(int alloc_msize)
}
c->max_tag += P9_ROW_MAXTAG;
}
- spin_unlock_irqrestore(&c->lock, flags);
+ spin_unlock(&c->lock);
}
row = tag / P9_ROW_MAXTAG;
col = tag % P9_ROW_MAXTAG;
@@ -909,7 +908,6 @@ static struct p9_fid *p9_fid_create(struct p9_client *clnt)
{
int ret;
struct p9_fid *fid;
- unsigned long flags;

p9_debug(P9_DEBUG_FID, "clnt %p\n", clnt);
fid = kmalloc(sizeof(struct p9_fid), GFP_KERNEL);
@@ -928,9 +926,9 @@ static struct p9_fid *p9_fid_create(struct p9_client *clnt)
fid->uid = current_fsuid();
fid->clnt = clnt;
fid->rdir = NULL;
- spin_lock_irqsave(&clnt->lock, flags);
+ spin_lock(&clnt->lock);
list_add(&fid->flist, &clnt->fidlist);
- spin_unlock_irqrestore(&clnt->lock, flags);
+ spin_unlock(&clnt->lock);

return fid;

@@ -942,14 +940,13 @@ static struct p9_fid *p9_fid_create(struct p9_client *clnt)
static void p9_fid_destroy(struct p9_fid *fid)
{
struct p9_client *clnt;
- unsigned long flags;

p9_debug(P9_DEBUG_FID, "fid %d\n", fid->fid);
clnt = fid->clnt;
p9_idpool_put(fid->fid, clnt->fidpool);
- spin_lock_irqsave(&clnt->lock, flags);
+ spin_lock(&clnt->lock);
list_del(&fid->flist);
- spin_unlock_irqrestore(&clnt->lock, flags);
+ spin_unlock(&clnt->lock);
kfree(fid->rdir);
kfree(fid);
}
diff --git a/net/9p/trans_fd.c b/net/9p/trans_fd.c
index 588bf88..96e1e68 100644
--- a/net/9p/trans_fd.c
+++ b/net/9p/trans_fd.c
@@ -197,15 +197,14 @@ static void p9_mux_poll_stop(struct p9_conn *m)
static void p9_conn_cancel(struct p9_conn *m, int err)
{
struct p9_req_t *req, *rtmp;
- unsigned long flags;
LIST_HEAD(cancel_list);

p9_debug(P9_DEBUG_ERROR, "mux %p err %d\n", m, err);

- spin_lock_irqsave(&m->client->lock, flags);
+ spin_lock(&m->client->lock);

if (m->err) {
- spin_unlock_irqrestore(&m->client->lock, flags);
+ spin_unlock(&m->client->lock);
return;
}

@@ -217,7 +216,7 @@ static void p9_conn_cancel(struct p9_conn *m, int err)
list_for_each_entry_safe(req, rtmp, &m->unsent_req_list, req_list) {
list_move(&req->req_list, &cancel_list);
}
- spin_unlock_irqrestore(&m->client->lock, flags);
+ spin_unlock(&m->client->lock);

list_for_each_entry_safe(req, rtmp, &cancel_list, req_list) {
p9_debug(P9_DEBUG_ERROR, "call back req %p\n", req);
--
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