[PATCH AUTOSEL 5.6 009/606] net/rds: Use ERR_PTR for rds_message_alloc_sgs()

Sasha Levin
2020-06-08T23:14:48Z

From: Jason Gunthorpe <jgg@mellanox.com>

commit 7dba92037baf3fa00b4880a31fd532542264994c upstream.

Returning the error code via a 'int *ret' when the function returns a
pointer is very un-kernely and causes gcc 10's static analysis to choke:

net/rds/message.c: In function ‘rds_message_map_pages’:
net/rds/message.c:358:10: warning: ‘ret’ may be used uninitialized in this function [-Wmaybe-uninitialized]
358 | return ERR_PTR(ret);

Use a typical ERR_PTR return instead.

Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/rds/message.c | 19 ++++++-------------
net/rds/rdma.c | 12 ++++++++----
net/rds/rds.h | 3 +--
net/rds/send.c | 6 ++++--
4 files changed, 19 insertions(+), 21 deletions(-)

diff --git a/net/rds/message.c b/net/rds/message.c
index 50f13f1d4ae0..2d43e13d6dd5 100644
--- a/net/rds/message.c
+++ b/net/rds/message.c
@@ -308,26 +308,20 @@ struct rds_message *rds_message_alloc(unsigned int extra_len, gfp_t gfp)
/*
* RDS ops use this to grab SG entries from the rm's sg pool.
*/
-struct scatterlist *rds_message_alloc_sgs(struct rds_message *rm, int nents,
- int *ret)
+struct scatterlist *rds_message_alloc_sgs(struct rds_message *rm, int nents)
{
struct scatterlist *sg_first = (struct scatterlist *) &rm[1];
struct scatterlist *sg_ret;

- if (WARN_ON(!ret))
- return NULL;
-
if (nents <= 0) {
pr_warn("rds: alloc sgs failed! nents <= 0\n");
- *ret = -EINVAL;
- return NULL;
+ return ERR_PTR(-EINVAL);
}

if (rm->m_used_sgs + nents > rm->m_total_sgs) {
pr_warn("rds: alloc sgs failed! total %d used %d nents %d\n",
rm->m_total_sgs, rm->m_used_sgs, nents);
- *ret = -ENOMEM;
- return NULL;
+ return ERR_PTR(-ENOMEM);
}

sg_ret = &sg_first[rm->m_used_sgs];
@@ -343,7 +337,6 @@ struct rds_message *rds_message_map_pages(unsigned long *page_addrs, unsigned in
unsigned int i;
int num_sgs = DIV_ROUND_UP(total_len, PAGE_SIZE);
int extra_bytes = num_sgs * sizeof(struct scatterlist);
- int ret;

rm = rds_message_alloc(extra_bytes, GFP_NOWAIT);
if (!rm)
@@ -352,10 +345,10 @@ struct rds_message *rds_message_map_pages(unsigned long *page_addrs, unsigned in
set_bit(RDS_MSG_PAGEVEC, &rm->m_flags);
rm->m_inc.i_hdr.h_len = cpu_to_be32(total_len);
rm->data.op_nents = DIV_ROUND_UP(total_len, PAGE_SIZE);
- rm->data.op_sg = rds_message_alloc_sgs(rm, num_sgs, &ret);
- if (!rm->data.op_sg) {
+ rm->data.op_sg = rds_message_alloc_sgs(rm, num_sgs);
+ if (IS_ERR(rm->data.op_sg)) {
rds_message_put(rm);
- return ERR_PTR(ret);
+ return ERR_CAST(rm->data.op_sg);
}

for (i = 0; i < rm->data.op_nents; ++i) {
diff --git a/net/rds/rdma.c b/net/rds/rdma.c
index 585e6b3b69ce..554ea7f0277f 100644
--- a/net/rds/rdma.c
+++ b/net/rds/rdma.c
@@ -664,9 +664,11 @@ int rds_cmsg_rdma_args(struct rds_sock *rs, struct rds_message *rm,
op->op_odp_mr = NULL;

WARN_ON(!nr_pages);
- op->op_sg = rds_message_alloc_sgs(rm, nr_pages, &ret);
- if (!op->op_sg)
+ op->op_sg = rds_message_alloc_sgs(rm, nr_pages);
+ if (IS_ERR(op->op_sg)) {
+ ret = PTR_ERR(op->op_sg);
goto out_pages;
+ }

if (op->op_notify || op->op_recverr) {
/* We allocate an uninitialized notifier here, because
@@ -905,9 +907,11 @@ int rds_cmsg_atomic(struct rds_sock *rs, struct rds_message *rm,
rm->atomic.op_silent = !!(args->flags & RDS_RDMA_SILENT);
rm->atomic.op_active = 1;
rm->atomic.op_recverr = rs->rs_recverr;
- rm->atomic.op_sg = rds_message_alloc_sgs(rm, 1, &ret);
- if (!rm->atomic.op_sg)
+ rm->atomic.op_sg = rds_message_alloc_sgs(rm, 1);
+ if (IS_ERR(rm->atomic.op_sg)) {
+ ret = PTR_ERR(rm->atomic.op_sg);
goto err;
+ }

/* verify 8 byte-aligned */
if (args->local_addr & 0x7) {
diff --git a/net/rds/rds.h b/net/rds/rds.h
index e4a603523083..b8b7ad766046 100644
--- a/net/rds/rds.h
+++ b/net/rds/rds.h
@@ -852,8 +852,7 @@ rds_conn_connecting(struct rds_connection *conn)

/* message.c */
struct rds_message *rds_message_alloc(unsigned int nents, gfp_t gfp);
-struct scatterlist *rds_message_alloc_sgs(struct rds_message *rm, int nents,
- int *ret);
+struct scatterlist *rds_message_alloc_sgs(struct rds_message *rm, int nents);
int rds_message_copy_from_user(struct rds_message *rm, struct iov_iter *from,
bool zcopy);
struct rds_message *rds_message_map_pages(unsigned long *page_addrs, unsigned int total_len);
diff --git a/net/rds/send.c b/net/rds/send.c
index 82dcd8b84fe7..68e2bdb08fd0 100644
--- a/net/rds/send.c
+++ b/net/rds/send.c
@@ -1274,9 +1274,11 @@ int rds_sendmsg(struct socket *sock, struct msghdr *msg, size_t payload_len)

/* Attach data to the rm */
if (payload_len) {
- rm->data.op_sg = rds_message_alloc_sgs(rm, num_sgs, &ret);
- if (!rm->data.op_sg)
+ rm->data.op_sg = rds_message_alloc_sgs(rm, num_sgs);
+ if (IS_ERR(rm->data.op_sg)) {
+ ret = PTR_ERR(rm->data.op_sg);
goto out;
+ }
ret = rds_message_copy_from_user(rm, &msg->msg_iter, zcopy);
if (ret)
goto out;
--
2.25.1