[PATCH 5/6] net/9p: Convert the in the 9p rpc call path to GFP_NOFS

From: Aneesh Kumar K.V
Date: Tue Mar 01 2011 - 03:52:15 EST


Without this we can cause reclaim allocation in writepage.

[ 3433.448430] =================================
[ 3433.449117] [ INFO: inconsistent lock state ]
[ 3433.449117] 2.6.38-rc5+ #84
[ 3433.449117] ---------------------------------
[ 3433.449117] inconsistent {RECLAIM_FS-ON-W} -> {IN-RECLAIM_FS-R} usage.
[ 3433.449117] kswapd0/505 [HC0[0]:SC0[0]:HE1:SE1] takes:
[ 3433.449117] (iprune_sem){+++++-}, at: [<ffffffff810ebbab>] shrink_icache_memory+0x45/0x2b1
[ 3433.449117] {RECLAIM_FS-ON-W} state was registered at:
[ 3433.449117] [<ffffffff8107fe5f>] mark_held_locks+0x52/0x70
[ 3433.449117] [<ffffffff8107ff02>] lockdep_trace_alloc+0x85/0x9f
[ 3433.449117] [<ffffffff810d353d>] slab_pre_alloc_hook+0x18/0x3c
[ 3433.449117] [<ffffffff810d3fd5>] kmem_cache_alloc+0x23/0xa2
[ 3433.449117] [<ffffffff8127be77>] idr_pre_get+0x2d/0x6f
[ 3433.449117] [<ffffffff815434eb>] p9_idpool_get+0x30/0xae
[ 3433.449117] [<ffffffff81540123>] p9_client_rpc+0xd7/0x9b0
[ 3433.449117] [<ffffffff815427b0>] p9_client_clunk+0x88/0xdb
[ 3433.449117] [<ffffffff811d56e5>] v9fs_evict_inode+0x3c/0x48
[ 3433.449117] [<ffffffff810eb511>] evict+0x1f/0x87
[ 3433.449117] [<ffffffff810eb5c0>] dispose_list+0x47/0xe3
[ 3433.449117] [<ffffffff810eb8da>] evict_inodes+0x138/0x14f
[ 3433.449117] [<ffffffff810d90e2>] generic_shutdown_super+0x57/0xe8
[ 3433.449117] [<ffffffff810d91e8>] kill_anon_super+0x11/0x50
[ 3433.449117] [<ffffffff811d4951>] v9fs_kill_super+0x49/0xab
[ 3433.449117] [<ffffffff810d926e>] deactivate_locked_super+0x21/0x46
[ 3433.449117] [<ffffffff810d9e84>] deactivate_super+0x40/0x44
[ 3433.449117] [<ffffffff810ef848>] mntput_no_expire+0x100/0x109
[ 3433.449117] [<ffffffff810f0aeb>] sys_umount+0x2f1/0x31c
[ 3433.449117] [<ffffffff8102c87b>] system_call_fastpath+0x16/0x1b
[ 3433.449117] irq event stamp: 192941
[ 3433.449117] hardirqs last enabled at (192941): [<ffffffff81568dcf>] _raw_spin_unlock_irq+0x2b/0x30
[ 3433.449117] hardirqs last disabled at (192940): [<ffffffff810b5f97>] shrink_inactive_list+0x290/0x2f5
[ 3433.449117] softirqs last enabled at (188470): [<ffffffff8105fd65>] __do_softirq+0x133/0x152
[ 3433.449117] softirqs last disabled at (188455): [<ffffffff8102d7cc>] call_softirq+0x1c/0x28
[ 3433.449117]
[ 3433.449117] other info that might help us debug this:
[ 3433.449117] 1 lock held by kswapd0/505:
[ 3433.449117] #0: (shrinker_rwsem){++++..}, at: [<ffffffff810b52e2>] shrink_slab+0x38/0x15f
[ 3433.449117]
[ 3433.449117] stack backtrace:
[ 3433.449117] Pid: 505, comm: kswapd0 Not tainted 2.6.38-rc5+ #84
[ 3433.449117] Call Trace:
[ 3433.449117] [<ffffffff8107fbce>] ? valid_state+0x17e/0x191
[ 3433.449117] [<ffffffff81036896>] ? save_stack_trace+0x28/0x45
[ 3433.449117] [<ffffffff81080426>] ? check_usage_forwards+0x0/0x87
[ 3433.449117] [<ffffffff8107fcf4>] ? mark_lock+0x113/0x22c
[ 3433.449117] [<ffffffff8108105f>] ? __lock_acquire+0x37a/0xcf7
[ 3433.449117] [<ffffffff8107fc0e>] ? mark_lock+0x2d/0x22c
[ 3433.449117] [<ffffffff81081077>] ? __lock_acquire+0x392/0xcf7
[ 3433.449117] [<ffffffff810b14d2>] ? determine_dirtyable_memory+0x15/0x28
[ 3433.449117] [<ffffffff81081a33>] ? lock_acquire+0x57/0x6d
[ 3433.449117] [<ffffffff810ebbab>] ? shrink_icache_memory+0x45/0x2b1
[ 3433.449117] [<ffffffff81567d85>] ? down_read+0x47/0x5c
[ 3433.449117] [<ffffffff810ebbab>] ? shrink_icache_memory+0x45/0x2b1
[ 3433.449117] [<ffffffff810ebbab>] ? shrink_icache_memory+0x45/0x2b1
[ 3433.449117] [<ffffffff810b5385>] ? shrink_slab+0xdb/0x15f
[ 3433.449117] [<ffffffff810b69bc>] ? kswapd+0x574/0x96a
[ 3433.449117] [<ffffffff810b6448>] ? kswapd+0x0/0x96a
[ 3433.449117] [<ffffffff810714e2>] ? kthread+0x7d/0x85
[ 3433.449117] [<ffffffff8102d6d4>] ? kernel_thread_helper+0x4/0x10
[ 3433.449117] [<ffffffff81569200>] ? restore_args+0x0/0x30
[ 3433.449117] [<ffffffff81071465>] ? kthread+0x0/0x85
[ 3433.449117] [<ffffffff8102d6d0>] ? kernel_thread_helper+0x0/0x10

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
---
net/9p/client.c | 10 +++++-----
net/9p/protocol.c | 6 +++---
net/9p/trans_fd.c | 2 +-
net/9p/trans_rdma.c | 6 +++---
net/9p/util.c | 2 +-
5 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/net/9p/client.c b/net/9p/client.c
index 347ec0c..2ccbf04 100644
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -223,7 +223,7 @@ static struct p9_req_t *p9_tag_alloc(struct p9_client *c, u16 tag)

req = &c->reqs[row][col];
if (!req->tc) {
- req->wq = kmalloc(sizeof(wait_queue_head_t), GFP_KERNEL);
+ req->wq = kmalloc(sizeof(wait_queue_head_t), GFP_NOFS);
if (!req->wq) {
printk(KERN_ERR "Couldn't grow tag array\n");
return ERR_PTR(-ENOMEM);
@@ -233,17 +233,17 @@ static struct p9_req_t *p9_tag_alloc(struct p9_client *c, u16 tag)
P9_TRANS_PREF_PAYLOAD_SEP) {
int alloc_msize = min(c->msize, 4096);
req->tc = kmalloc(sizeof(struct p9_fcall)+alloc_msize,
- GFP_KERNEL);
+ GFP_NOFS);
req->tc->capacity = alloc_msize;
req->rc = kmalloc(sizeof(struct p9_fcall)+alloc_msize,
- GFP_KERNEL);
+ GFP_NOFS);
req->rc->capacity = alloc_msize;
} else {
req->tc = kmalloc(sizeof(struct p9_fcall)+c->msize,
- GFP_KERNEL);
+ GFP_NOFS);
req->tc->capacity = c->msize;
req->rc = kmalloc(sizeof(struct p9_fcall)+c->msize,
- GFP_KERNEL);
+ GFP_NOFS);
req->rc->capacity = c->msize;
}
if ((!req->tc) || (!req->rc)) {
diff --git a/net/9p/protocol.c b/net/9p/protocol.c
index 2ce515b..8a4084f 100644
--- a/net/9p/protocol.c
+++ b/net/9p/protocol.c
@@ -205,7 +205,7 @@ p9pdu_vreadf(struct p9_fcall *pdu, int proto_version, const char *fmt,
if (errcode)
break;

- *sptr = kmalloc(len + 1, GFP_KERNEL);
+ *sptr = kmalloc(len + 1, GFP_NOFS);
if (*sptr == NULL) {
errcode = -EFAULT;
break;
@@ -273,7 +273,7 @@ p9pdu_vreadf(struct p9_fcall *pdu, int proto_version, const char *fmt,
if (!errcode) {
*wnames =
kmalloc(sizeof(char *) * *nwname,
- GFP_KERNEL);
+ GFP_NOFS);
if (!*wnames)
errcode = -ENOMEM;
}
@@ -317,7 +317,7 @@ p9pdu_vreadf(struct p9_fcall *pdu, int proto_version, const char *fmt,
*wqids =
kmalloc(*nwqid *
sizeof(struct p9_qid),
- GFP_KERNEL);
+ GFP_NOFS);
if (*wqids == NULL)
errcode = -ENOMEM;
}
diff --git a/net/9p/trans_fd.c b/net/9p/trans_fd.c
index 078eb16..800c55b 100644
--- a/net/9p/trans_fd.c
+++ b/net/9p/trans_fd.c
@@ -349,7 +349,7 @@ static void p9_read_work(struct work_struct *work)

if (m->req->rc == NULL) {
m->req->rc = kmalloc(sizeof(struct p9_fcall) +
- m->client->msize, GFP_KERNEL);
+ m->client->msize, GFP_NOFS);
if (!m->req->rc) {
m->req = NULL;
err = -ENOMEM;
diff --git a/net/9p/trans_rdma.c b/net/9p/trans_rdma.c
index 17c5ba7..ccac42a 100644
--- a/net/9p/trans_rdma.c
+++ b/net/9p/trans_rdma.c
@@ -425,7 +425,7 @@ static int rdma_request(struct p9_client *client, struct p9_req_t *req)
struct p9_rdma_context *rpl_context = NULL;

/* Allocate an fcall for the reply */
- rpl_context = kmalloc(sizeof *rpl_context, GFP_KERNEL);
+ rpl_context = kmalloc(sizeof *rpl_context, GFP_NOFS);
if (!rpl_context) {
err = -ENOMEM;
goto err_close;
@@ -438,7 +438,7 @@ static int rdma_request(struct p9_client *client, struct p9_req_t *req)
*/
if (!req->rc) {
req->rc = kmalloc(sizeof(struct p9_fcall)+client->msize,
- GFP_KERNEL);
+ GFP_NOFS);
if (req->rc) {
req->rc->sdata = (char *) req->rc +
sizeof(struct p9_fcall);
@@ -469,7 +469,7 @@ static int rdma_request(struct p9_client *client, struct p9_req_t *req)
req->rc = NULL;

/* Post the request */
- c = kmalloc(sizeof *c, GFP_KERNEL);
+ c = kmalloc(sizeof *c, GFP_NOFS);
if (!c) {
err = -ENOMEM;
goto err_free1;
diff --git a/net/9p/util.c b/net/9p/util.c
index e048701..b84619b 100644
--- a/net/9p/util.c
+++ b/net/9p/util.c
@@ -92,7 +92,7 @@ int p9_idpool_get(struct p9_idpool *p)
unsigned long flags;

retry:
- if (idr_pre_get(&p->pool, GFP_KERNEL) == 0)
+ if (idr_pre_get(&p->pool, GFP_NOFS) == 0)
return 0;

spin_lock_irqsave(&p->lock, flags);
--
1.7.1

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