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Subject[PATCH 2/9] um/drivers/vector_user: Less checks in user_init_raw_fds() after error detection
From
Date
From: Markus Elfring <elfring@users.sourceforge.net>
Date: Sun, 11 Mar 2018 11:40:14 +0100

Up to two checks could be repeated by the user_init_raw_fds() function
during error handling even if the relevant properties can be determined
for the involved variables before by source code analysis.

* Adjust jump targets so that an extra check can be omitted at the end.

* Delete an initialisation for the local variable "rxfd"
which became unnecessary with this refactoring.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
---
arch/um/drivers/vector_user.c | 61 ++++++++++++++++++++-----------------------
1 file changed, 28 insertions(+), 33 deletions(-)

diff --git a/arch/um/drivers/vector_user.c b/arch/um/drivers/vector_user.c
index d6a6207d4061..037cd85ee424 100644
--- a/arch/um/drivers/vector_user.c
+++ b/arch/um/drivers/vector_user.c
@@ -207,54 +207,46 @@ static struct vector_fds *user_init_tap_fds(struct arglist *ifspec)
static struct vector_fds *user_init_raw_fds(struct arglist *ifspec)
{
struct ifreq ifr;
- int rxfd = -1, txfd = -1;
+ int rxfd, txfd = -1;
struct sockaddr_ll sock;
- int err = -ENOMEM;
- char *iface;
struct vector_fds *result;
int optval = 1;
+ int err;
+ char *iface = uml_vector_fetch_arg(ifspec, TOKEN_IFNAME);

-
- iface = uml_vector_fetch_arg(ifspec, TOKEN_IFNAME);
- if (iface == NULL)
- goto cleanup;
+ if (!iface) {
+ err = -ENOMEM;
+ goto report_failure;
+ }

rxfd = socket(AF_PACKET, SOCK_RAW, ETH_P_ALL);
- if (rxfd == -1) {
- err = -errno;
- goto cleanup;
- }
+ if (rxfd == -1)
+ goto set_error_code;
+
txfd = socket(AF_PACKET, SOCK_RAW, 0); /* Turn off RX on this fd */
- if (txfd == -1) {
- err = -errno;
- goto cleanup;
- }
+ if (txfd == -1)
+ goto set_error_code;
+
memset(&ifr, 0, sizeof(ifr));
strncpy((char *)&ifr.ifr_name, iface, sizeof(ifr.ifr_name) - 1);
- if (ioctl(rxfd, SIOCGIFINDEX, (void *) &ifr) < 0) {
- err = -errno;
- goto cleanup;
- }
+ if (ioctl(rxfd, SIOCGIFINDEX, (void *) &ifr) < 0)
+ goto set_error_code;

sock.sll_family = AF_PACKET;
sock.sll_protocol = htons(ETH_P_ALL);
sock.sll_ifindex = ifr.ifr_ifindex;

- if (bind(rxfd,
- (struct sockaddr *) &sock, sizeof(struct sockaddr_ll)) < 0) {
- err = -errno;
- goto cleanup;
- }
+ if (bind(rxfd, (struct sockaddr *)&sock, sizeof(struct sockaddr_ll))
+ < 0)
+ goto set_error_code;

sock.sll_family = AF_PACKET;
sock.sll_protocol = htons(ETH_P_IP);
sock.sll_ifindex = ifr.ifr_ifindex;

- if (bind(txfd,
- (struct sockaddr *) &sock, sizeof(struct sockaddr_ll)) < 0) {
- err = -errno;
- goto cleanup;
- }
+ if (bind(txfd, (struct sockaddr *)&sock, sizeof(struct sockaddr_ll))
+ < 0)
+ goto set_error_code;

if (setsockopt(txfd,
SOL_PACKET, PACKET_QDISC_BYPASS,
@@ -270,12 +262,15 @@ static struct vector_fds *user_init_raw_fds(struct arglist *ifspec)
result->remote_addr_size = 0;
}
return result;
-cleanup:
- printk(UM_KERN_ERR "user_init_raw: init failed, error %d", err);
- if (rxfd >= 0)
- os_close_file(rxfd);
+
+set_error_code:
+ err = -errno;
+ os_close_file(rxfd);
+
if (txfd >= 0)
os_close_file(txfd);
+report_failure:
+ printk(UM_KERN_ERR "%s: init failed: %d", __func__, err);
return NULL;
}

--
2.16.2
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