From: Emil Velikov emil.velikov@collabora.com
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@collabora.com Signed-off-by: Emil Velikov emil.velikov@collabora.com Tested-by: Robert Foss robert.foss@collabora.com (v1) Reviewed-by: Robert Foss robert.foss@collabora.com (v1) Reviewed-by: Eric Engestrom eric@engestrom.ch (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; }
/**