[vd_agent_linux] device-info: remove g_list_length() on compare_addresses()

Submitted by Frediano Ziglio on July 19, 2019, 10:54 a.m.

Details

Message ID 20190719105444.7537-1-fziglio@redhat.com
State Accepted
Commit 66935d134e1f359eda5cfac053b0bf716811670a
Headers show
Series "device-info: remove g_list_length() on compare_addresses()" ( rev: 1 ) in Spice

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Commit Message

Frediano Ziglio July 19, 2019, 10:54 a.m.
From: Victor Toso <me@victortoso.com>

The g_list_length() function does iterate over both lists to compare
its length. Considering that we use this to check for true/false and
we will iterate again on both lists, we can do so once.

This should also avoid covscan/clang warnings:

 | spice-vdagent-0.19.0/src/vdagent/device-info.c:216:27: warning: Access to field 'data' results in a dereference of a null pointer (loaded from variable 'lb')
 | #        PciDevice *devb = lb->data;
 | #                          ^
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:397:5: note: Taking false branch
 | #    if (!user_pci_addr) {
 | #    ^
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:407:22: note: Calling 'find_device_at_pci_address'
 | #    char *dev_path = find_device_at_pci_address(user_pci_addr, &vendor_id, &device_id);
 | #                     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:329:5: note: Taking true branch
 | #    g_return_val_if_fail(pci_addr != NULL, NULL);
 | #    ^
 | /usr/include/glib-2.0/glib/gmessages.h:594:9: note: expanded from macro 'g_return_val_if_fail'
 | #     if G_LIKELY(expr) { } else                                         \
 | #        ^
 | /usr/include/glib-2.0/glib/gmacros.h:385:43: note: expanded from macro 'G_LIKELY'
 | ##define G_LIKELY(expr) (__builtin_expect (_G_BOOLEAN_EXPR((expr)), 1))
 | #                                          ^
 | /usr/include/glib-2.0/glib/gmacros.h:379:4: note: expanded from macro '_G_BOOLEAN_EXPR'
 | #   if (expr)                                    \
 | #   ^
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:329:5: note: Taking true branch
 | /usr/include/glib-2.0/glib/gmessages.h:594:6: note: expanded from macro 'g_return_val_if_fail'
 | #     if G_LIKELY(expr) { } else                                         \
 | #     ^
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:329:5: note: Loop condition is false.  Exiting loop
 | /usr/include/glib-2.0/glib/gmessages.h:593:40: note: expanded from macro 'g_return_val_if_fail'
 | ##define g_return_val_if_fail(expr,val)  G_STMT_START{                   \
 | #                                        ^
 | /usr/include/glib-2.0/glib/gmacros.h:346:23: note: expanded from macro 'G_STMT_START'
 | ##define G_STMT_START  do
 | #                      ^
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:330:5: note: Taking true branch
 | #    g_return_val_if_fail(device_id != NULL, NULL);
 | #    ^
 | /usr/include/glib-2.0/glib/gmessages.h:594:9: note: expanded from macro 'g_return_val_if_fail'
 | #     if G_LIKELY(expr) { } else                                         \
 | #        ^
 | /usr/include/glib-2.0/glib/gmacros.h:385:43: note: expanded from macro 'G_LIKELY'
 | ##define G_LIKELY(expr) (__builtin_expect (_G_BOOLEAN_EXPR((expr)), 1))
 | #                                          ^
 | /usr/include/glib-2.0/glib/gmacros.h:379:4: note: expanded from macro '_G_BOOLEAN_EXPR'
 | #   if (expr)                                    \
 | #   ^
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:330:5: note: Taking true branch
 | /usr/include/glib-2.0/glib/gmessages.h:594:6: note: expanded from macro 'g_return_val_if_fail'
 | #     if G_LIKELY(expr) { } else                                         \
 | #     ^
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:330:5: note: Loop condition is false.  Exiting loop
 | /usr/include/glib-2.0/glib/gmessages.h:593:40: note: expanded from macro 'g_return_val_if_fail'
 | ##define g_return_val_if_fail(expr,val)  G_STMT_START{                   \
 | #                                        ^
 | /usr/include/glib-2.0/glib/gmacros.h:346:23: note: expanded from macro 'G_STMT_START'
 | ##define G_STMT_START  do
 | #                      ^
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:331:5: note: Taking true branch
 | #    g_return_val_if_fail(vendor_id != NULL, NULL);
 | #    ^
 | /usr/include/glib-2.0/glib/gmessages.h:594:9: note: expanded from macro 'g_return_val_if_fail'
 | #     if G_LIKELY(expr) { } else                                         \
 | #        ^
 | /usr/include/glib-2.0/glib/gmacros.h:385:43: note: expanded from macro 'G_LIKELY'
 | ##define G_LIKELY(expr) (__builtin_expect (_G_BOOLEAN_EXPR((expr)), 1))
 | #                                          ^
 | /usr/include/glib-2.0/glib/gmacros.h:379:4: note: expanded from macro '_G_BOOLEAN_EXPR'
 | #   if (expr)                                    \
 | #   ^
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:331:5: note: Taking true branch
 | /usr/include/glib-2.0/glib/gmessages.h:594:6: note: expanded from macro 'g_return_val_if_fail'
 | #     if G_LIKELY(expr) { } else                                         \
 | #     ^
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:331:5: note: Loop condition is false.  Exiting loop
 | /usr/include/glib-2.0/glib/gmessages.h:593:40: note: expanded from macro 'g_return_val_if_fail'
 | ##define g_return_val_if_fail(expr,val)  G_STMT_START{                   \
 | #                                        ^
 | /usr/include/glib-2.0/glib/gmacros.h:346:23: note: expanded from macro 'G_STMT_START'
 | ##define G_STMT_START  do
 | #                      ^
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:334:5: note: Loop condition is true.  Entering loop body
 | #    for (int i = 0; i < 10; ++i) {
 | #    ^
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:340:13: note: Assuming the condition is false
 | #        if (stat(dev_path, &buf) != 0) {
 | #            ^~~~~~~~~~~~~~~~~~~~~~~~~
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:340:9: note: Taking false branch
 | #        if (stat(dev_path, &buf) != 0) {
 | #        ^
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:355:13: note: Assuming the condition is false
 | #        if (realpath(sys_path, device_link) == NULL) {
 | #            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:355:9: note: Taking false branch
 | #        if (realpath(sys_path, device_link) == NULL) {
 | #        ^
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:361:36: note: Calling 'parse_pci_address_from_sysfs_path'
 | #        PciAddress *drm_pci_addr = parse_pci_address_from_sysfs_path(device_link);
 | #                                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:129:9: note: Assuming 'pos' is non-null
 | #    if (!pos) {
 | #        ^~~~
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:129:5: note: Taking false branch
 | #    if (!pos) {
 | #    ^
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:136:9: note: Assuming 'pos' is non-null
 | #    if (!pos) {
 | #        ^~~~
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:136:5: note: Taking false branch
 | #    if (!pos) {
 | #    ^
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:142:9: note: Assuming 'pos' is non-null
 | #    if (!pos) {
 | #        ^~~~
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:142:5: note: Taking false branch
 | #    if (!pos) {
 | #    ^
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:146:27: note: Calling 'pci_address_new'
 | #    PciAddress *address = pci_address_new();
 | #                          ^~~~~~~~~~~~~~~~~
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:61:12: note: Taking false branch
 | #    return g_new0(PciAddress, 1);
 | #           ^
 | /usr/include/glib-2.0/glib/gmem.h:279:42: note: expanded from macro 'g_new0'
 | ##define g_new0(struct_type, n_structs)                  _G_NEW (struct_type, n_structs, malloc0)
 | #                                                        ^
 | /usr/include/glib-2.0/glib/gmem.h:211:4: note: expanded from macro '_G_NEW'
 | #          if (__s == 1)                                         \
 | #          ^
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:61:12: note: Left side of '&&' is false
 | /usr/include/glib-2.0/glib/gmem.h:279:42: note: expanded from macro 'g_new0'
 | ##define g_new0(struct_type, n_structs)                  _G_NEW (struct_type, n_structs, malloc0)
 | #                                                        ^
 | /usr/include/glib-2.0/glib/gmem.h:213:40: note: expanded from macro '_G_NEW'
 | #          else if (__builtin_constant_p (__n) &&                \
 | #                                              ^
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:61:12: note: Null pointer value stored to field 'devices'
 | #    return g_new0(PciAddress, 1);
 | #           ^~~~~~~~~~~~~~~~~~~~~
 | /usr/include/glib-2.0/glib/gmem.h:279:42: note: expanded from macro 'g_new0'
 | ##define g_new0(struct_type, n_structs)                  _G_NEW (struct_type, n_structs, malloc0)
 | #                                                        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 | /usr/include/glib-2.0/glib/gmem.h:217:12: note: expanded from macro '_G_NEW'
 | #            __p = g_##func##_n (__n, __s);                      \
 | #                  ^~~~~~~~~~~~~~~~~~~~~~~
 | <scratch space>:76:1: note: expanded from here
 | #g_malloc0_n
 | #^
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:146:27: note: Returning from 'pci_address_new'
 | #    PciAddress *address = pci_address_new();
 | #                          ^~~~~~~~~~~~~~~~~
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:149:5: note: Loop condition is true.  Entering loop body
 | #    while (pos) {
 | #    ^
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:150:26: note: Taking false branch
 | #        PciDevice *dev = g_new0(PciDevice, 1);
 | #                         ^
 | /usr/include/glib-2.0/glib/gmem.h:279:42: note: expanded from macro 'g_new0'
 | ##define g_new0(struct_type, n_structs)                  _G_NEW (struct_type, n_structs, malloc0)
 | #                                                        ^
 | /usr/include/glib-2.0/glib/gmem.h:211:4: note: expanded from macro '_G_NEW'
 | #          if (__s == 1)                                         \
 | #          ^
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:150:26: note: Left side of '&&' is false
 | /usr/include/glib-2.0/glib/gmem.h:279:42: note: expanded from macro 'g_new0'
 | ##define g_new0(struct_type, n_structs)                  _G_NEW (struct_type, n_structs, malloc0)
 | #                                                        ^
 | /usr/include/glib-2.0/glib/gmem.h:213:40: note: expanded from macro '_G_NEW'
 | #          else if (__builtin_constant_p (__n) &&                \
 | #                                              ^
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:152:9: note: Taking true branch
 | #        if (!parse_pci_device(pos + 1, next, dev)) {
 | #        ^
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:154:13: note:  Execution continues on line 159
 | #            break;
 | #            ^
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:361:36: note: Returning from 'parse_pci_address_from_sysfs_path'
 | #        PciAddress *drm_pci_addr = parse_pci_address_from_sysfs_path(device_link);
 | #                                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:362:9: note: Taking false branch
 | #        if (!drm_pci_addr) {
 | #        ^
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:367:14: note: Calling 'compare_addresses'
 | #        if (!compare_addresses(pci_addr, drm_pci_addr)) {
 | #             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:207:11: note: Assuming the condition is true
 | #    if (!(a->domain == b->domain
 | #          ^~~~~~~~~~~~~~~~~~~~~~
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:207:11: note: Left side of '&&' is true
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:208:12: note: Assuming the condition is true
 | #        && g_list_length(a->devices) == g_list_length(b->devices))) {
 | #           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:207:5: note: Taking false branch
 | #    if (!(a->domain == b->domain
 | #    ^
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:212:35: note: 'lb' initialized to a null pointer value
 | #    for (GList *la = a->devices, *lb = b->devices;
 | #                                  ^~
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:213:10: note: Assuming 'la' is not equal to NULL
 | #         la != NULL;
 | #         ^~~~~~~~~~
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:212:5: note: Loop condition is true.  Entering loop body
 | #    for (GList *la = a->devices, *lb = b->devices;
 | #    ^
 | spice-vdagent-0.19.0/src/vdagent/device-info.c:216:27: note: Access to field 'data' results in a dereference of a null pointer (loaded from variable 'lb')
 | #        PciDevice *devb = lb->data;
 | #                          ^~
 | #  214|            la = la->next, lb = lb->next) {
 | #  215|           PciDevice *deva = la->data;
 | #  216|->         PciDevice *devb = lb->data;
 | #  217|
 | #  218|           if (deva->slot != devb->slot

Signed-off-by: Victor Toso <victortoso@redhat.com>
---
 src/vdagent/device-info.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

Patch hide | download patch | download mbox

diff --git a/src/vdagent/device-info.c b/src/vdagent/device-info.c
index 4983543..6b0e28f 100644
--- a/src/vdagent/device-info.c
+++ b/src/vdagent/device-info.c
@@ -204,13 +204,13 @@  static PciAddress* parse_pci_address_from_spice(char *input)
 static bool compare_addresses(PciAddress *a, PciAddress *b)
 {
     // only check domain, slot, and function
-    if (!(a->domain == b->domain
-        && g_list_length(a->devices) == g_list_length(b->devices))) {
+    if (a->domain != b->domain) {
         return false;
     }
 
-    for (GList *la = a->devices, *lb = b->devices;
-         la != NULL;
+    const GList *la, *lb;
+    for (la = a->devices, lb = b->devices;
+         la != NULL && lb != NULL;
          la = la->next, lb = lb->next) {
         PciDevice *deva = la->data;
         PciDevice *devb = lb->data;
@@ -220,7 +220,9 @@  static bool compare_addresses(PciAddress *a, PciAddress *b)
             return false;
         }
     }
-    return true;
+
+    /* True only if both have the same length */
+    return (la == NULL && lb == NULL);
 }
 
 // Connector type names from xorg modesetting driver