In both functions, use an array of 8 (arbitrary but should be big enough
for all current uses) iov and avoid having to kmalloc the array
for the common case.
If 8 is too small, then fall back to the original behaviour and use
kmalloc/kfree.
This should not change any behaviour but should save us a tiny amount of
cpu cycles.
Signed-off-by: Ronnie Sahlberg <lsahlber@xxxxxxxxxx>
---
fs/cifs/transport.c | 33 +++++++++++++++++++++++----------
1 file changed, 23 insertions(+), 10 deletions(-)
diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
index e678307bb7a0..510f41a435c8 100644
--- a/fs/cifs/transport.c
+++ b/fs/cifs/transport.c
@@ -38,6 +38,9 @@
#include "cifsproto.h"
#include "cifs_debug.h"
+/* Max number of iovectors we can use off the stack when sending requests. */
+#define CIFS_MAX_IOV_SIZE 8
+
void
cifs_wake_up_task(struct mid_q_entry *mid)
{
@@ -803,12 +806,16 @@ SendReceive2(const unsigned int xid, struct cifs_ses *ses,
const int flags, struct kvec *resp_iov)
{
struct smb_rqst rqst;
- struct kvec *new_iov;
+ struct kvec s_iov[CIFS_MAX_IOV_SIZE], *new_iov;
int rc;
- new_iov = kmalloc(sizeof(struct kvec) * (n_vec + 1), GFP_KERNEL);
- if (!new_iov)
- return -ENOMEM;
+ if (n_vec + 1 > CIFS_MAX_IOV_SIZE) {
+ new_iov = kmalloc(sizeof(struct kvec) * (n_vec + 1),
+ GFP_KERNEL);
+ if (!new_iov)
+ return -ENOMEM;
+ } else
+ new_iov = s_iov;
/* 1st iov is a RFC1001 length followed by the rest of the packet */
memcpy(new_iov + 1, iov, (sizeof(struct kvec) * n_vec));
@@ -823,7 +830,8 @@ SendReceive2(const unsigned int xid, struct cifs_ses *ses,
rqst.rq_nvec = n_vec + 1;
rc = cifs_send_recv(xid, ses, &rqst, resp_buf_type, flags, resp_iov);
- kfree(new_iov);
+ if (n_vec + 1 > CIFS_MAX_IOV_SIZE)
+ kfree(new_iov);
return rc;
}
@@ -834,15 +842,19 @@ smb2_send_recv(const unsigned int xid, struct cifs_ses *ses,
const int flags, struct kvec *resp_iov)
{
struct smb_rqst rqst;
- struct kvec *new_iov;
+ struct kvec s_iov[CIFS_MAX_IOV_SIZE], *new_iov;
int rc;
int i;
__u32 count;
__be32 rfc1002_marker;
- new_iov = kmalloc(sizeof(struct kvec) * (n_vec + 1), GFP_KERNEL);
- if (!new_iov)
- return -ENOMEM;
+ if (n_vec + 1 > CIFS_MAX_IOV_SIZE) {
+ new_iov = kmalloc(sizeof(struct kvec) * (n_vec + 1),
+ GFP_KERNEL);
+ if (!new_iov)
+ return -ENOMEM;
+ } else
+ new_iov = s_iov;
/* 1st iov is an RFC1002 Session Message length */
memcpy(new_iov + 1, iov, (sizeof(struct kvec) * n_vec));
@@ -861,7 +873,8 @@ smb2_send_recv(const unsigned int xid, struct cifs_ses *ses,
rqst.rq_nvec = n_vec + 1;
rc = cifs_send_recv(xid, ses, &rqst, resp_buf_type, flags, resp_iov);
- kfree(new_iov);
+ if (n_vec + 1 > CIFS_MAX_IOV_SIZE)
+ kfree(new_iov);
return rc;
}
--
2.13.3
--
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