From: Emil Velikov <emil.velikov@xxxxxxxxxxxxx>
Currently we dynamically allocate 16 pointers and reallocate more as
needed.
Instead, allocate the maximum number (256) on stack - the number is
small enough and is unlikely to change in the foreseeable future.
This allows us to simplify the error handling and even shed a few bytes
off the final binary.
v2:
- add a define & description behind the magic 256 (Rob)
- report error to strerr and skip when over 256 device nodes (Rob)
Cc: Robert Foss <robert.foss@xxxxxxxxxxxxx>
Signed-off-by: Emil Velikov <emil.velikov@xxxxxxxxxxxxx>
Tested-by: Robert Foss <robert.foss@xxxxxxxxxxxxx> (v1)
Reviewed-by: Robert Foss <robert.foss@xxxxxxxxxxxxx> (v1)
Reviewed-by: Eric Engestrom <eric@xxxxxxxxxxxx> (v1)
---
xf86drm.c | 79 ++++++++++++++++---------------------------------------
1 file changed, 23 insertions(+), 56 deletions(-)
diff --git a/xf86drm.c b/xf86drm.c
index 114cf855..02da3e1f 100644
--- a/xf86drm.c
+++ b/xf86drm.c
@@ -3766,6 +3766,13 @@ drm_device_has_rdev(drmDevicePtr device, dev_t find_rdev)
return false;
}
+/*
+ * The kernel drm core has a number of places that assume maximum of
+ * 3x64 devices nodes. That's 64 for each of primary, control and
+ * render nodes. Rounded it up to 256 for simplicity.
+ */
+#define MAX_DRM_NODES 256
+
/**
* Get information about the opened drm device
*
@@ -3846,7 +3853,7 @@ int drmGetDevice2(int fd, uint32_t flags, drmDevicePtr *device)
return 0;
#else
- drmDevicePtr *local_devices;
+ drmDevicePtr local_devices[MAX_DRM_NODES];
drmDevicePtr d;
DIR *sysdir;
struct dirent *dent;
@@ -3854,7 +3861,6 @@ int drmGetDevice2(int fd, uint32_t flags, drmDevicePtr *device)
int subsystem_type;
int maj, min;
int ret, i, node_count;
- int max_count = 16;
dev_t find_rdev;
if (drm_device_validate_flags(flags))
@@ -3877,15 +3883,9 @@ int drmGetDevice2(int fd, uint32_t flags, drmDevicePtr *device)
if (subsystem_type < 0)
return subsystem_type;
- local_devices = calloc(max_count, sizeof(drmDevicePtr));
- if (local_devices == NULL)
- return -ENOMEM;
-
sysdir = opendir(DRM_DIR_NAME);
- if (!sysdir) {
- ret = -errno;
- goto free_locals;
- }
+ if (!sysdir)
+ return -errno;
i = 0;
while ((dent = readdir(sysdir))) {
@@ -3893,16 +3893,12 @@ int drmGetDevice2(int fd, uint32_t flags, drmDevicePtr *device)
if (ret)
continue;
- if (i >= max_count) {
- drmDevicePtr *temp;
-
- max_count += 16;
- temp = realloc(local_devices, max_count * sizeof(drmDevicePtr));
- if (!temp)
- goto free_devices;
- local_devices = temp;
+ if (i >= MAX_DRM_NODES) {
+ fprintf(stderr, "More than %d drm nodes detected. "
+ "Please report a bug - that should not happen.\n"
+ "Skipping extra nodes\n", MAX_DRM_NODES);
+ break;
}
-
local_devices[i] = d;
i++;
}
@@ -3921,18 +3917,9 @@ int drmGetDevice2(int fd, uint32_t flags, drmDevicePtr *device)
}
closedir(sysdir);
- free(local_devices);
if (*device == NULL)
return -ENODEV;
return 0;
-
-free_devices:
- drmFreeDevices(local_devices, i);
- closedir(sysdir);
-
-free_locals:
- free(local_devices);
- return ret;
#endif
}
@@ -3968,25 +3955,18 @@ int drmGetDevice(int fd, drmDevicePtr *device)
*/
int drmGetDevices2(uint32_t flags, drmDevicePtr devices[], int max_devices)
{
- drmDevicePtr *local_devices;
+ drmDevicePtr local_devices[MAX_DRM_NODES];
drmDevicePtr device;
DIR *sysdir;
struct dirent *dent;
int ret, i, node_count, device_count;
- int max_count = 16;
if (drm_device_validate_flags(flags))
return -EINVAL;
- local_devices = calloc(max_count, sizeof(drmDevicePtr));
- if (local_devices == NULL)
- return -ENOMEM;
-
sysdir = opendir(DRM_DIR_NAME);
- if (!sysdir) {
- ret = -errno;
- goto free_locals;
- }
+ if (!sysdir)
+ return -errno;
i = 0;
while ((dent = readdir(sysdir))) {
@@ -3994,16 +3974,12 @@ int drmGetDevices2(uint32_t flags, drmDevicePtr devices[], int max_devices)
if (ret)
continue;
- if (i >= max_count) {
- drmDevicePtr *temp;
-
- max_count += 16;
- temp = realloc(local_devices, max_count * sizeof(drmDevicePtr));
- if (!temp)
- goto free_devices;
- local_devices = temp;
+ if (i >= MAX_DRM_NODES) {
+ fprintf(stderr, "More than %d drm nodes detected. "
+ "Please report a bug - that should not happen.\n"
+ "Skipping extra nodes\n", MAX_DRM_NODES);
+ break;
}
-
local_devices[i] = device;
i++;
}
@@ -4025,16 +4001,7 @@ int drmGetDevices2(uint32_t flags, drmDevicePtr devices[], int max_devices)
}
closedir(sysdir);
- free(local_devices);
return device_count;
-
-free_devices:
- drmFreeDevices(local_devices, i);
- closedir(sysdir);
-
-free_locals:
- free(local_devices);
- return ret;
}
/**
