Re: [PATCH linux-next] SUNRPC: rpcrdma_register_default_external: Dynamically allocate ib_phys_buf

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 




This is the result of 2773395b34883fe54418de188733a63bb38e0ad6. Steve might want to weigh in on this since it was done for performance reasons.

Tom

On 3/10/13 10:39 AM, Tim Gardner wrote:
rpcrdma_register_default_external() is several frames into
the call stack which goes deeper yet. You run the risk of stack
corruption by declaring such a large automatic variable,
so dynamically allocate the array of 'struct ib_phys_buf' objects in
order to silence the frame-larger-than warning.

net/sunrpc/xprtrdma/verbs.c: In function 'rpcrdma_register_default_external':
net/sunrpc/xprtrdma/verbs.c:1774:1: warning: the frame size of 1056 bytes is larger than 1024 bytes [-Wframe-larger-than=]

gcc version 4.6.3

Cc: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>
Cc: "J. Bruce Fields" <bfields@xxxxxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Tom Tucker <tom@xxxxxx>
Cc: Haggai Eran <haggaie@xxxxxxxxxxxx>
Cc: Or Gerlitz <ogerlitz@xxxxxxxxxxxx>
Cc: Shani Michaeli <shanim@xxxxxxxxxxxx>
Cc: linux-nfs@xxxxxxxxxxxxxxx
Cc: netdev@xxxxxxxxxxxxxxx
Signed-off-by: Tim Gardner <tim.gardner@xxxxxxxxxxxxx>
---
  net/sunrpc/xprtrdma/verbs.c |    7 ++++++-
  1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
index 93726560..0916467 100644
--- a/net/sunrpc/xprtrdma/verbs.c
+++ b/net/sunrpc/xprtrdma/verbs.c
@@ -1736,9 +1736,13 @@ rpcrdma_register_default_external(struct rpcrdma_mr_seg *seg,
  	int mem_priv = (writing ? IB_ACCESS_REMOTE_WRITE :
  				  IB_ACCESS_REMOTE_READ);
  	struct rpcrdma_mr_seg *seg1 = seg;
-	struct ib_phys_buf ipb[RPCRDMA_MAX_DATA_SEGS];
+	struct ib_phys_buf *ipb;
  	int len, i, rc = 0;
+ ipb = kmalloc(sizeof(*ipb) * RPCRDMA_MAX_DATA_SEGS, GFP_KERNEL);
+	if (!ipb)
+		return -ENOMEM;
+
  	if (*nsegs > RPCRDMA_MAX_DATA_SEGS)
  		*nsegs = RPCRDMA_MAX_DATA_SEGS;
  	for (len = 0, i = 0; i < *nsegs;) {
@@ -1770,6 +1774,7 @@ rpcrdma_register_default_external(struct rpcrdma_mr_seg *seg,
  		seg1->mr_len = len;
  	}
  	*nsegs = i;
+	kfree(ipb);
  	return rc;
  }

--
To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html


[Index of Archives]     [Linux Filesystem Development]     [Linux USB Development]     [Linux Media Development]     [Video for Linux]     [Linux NILFS]     [Linux Audio Users]     [Yosemite Info]     [Linux SCSI]

  Powered by Linux