Hey Emil,
On 2018-06-25 19:36, Emil Velikov wrote:
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.
Signed-off-by: Emil Velikov <emil.velikov@xxxxxxxxxxxxx>
---
xf86drm.c | 64 ++++++-------------------------------------------------
1 file changed, 6 insertions(+), 58 deletions(-)
diff --git a/xf86drm.c b/xf86drm.c
index 114cf855..d4810740 100644
--- a/xf86drm.c
+++ b/xf86drm.c
@@ -3846,7 +3846,7 @@ int drmGetDevice2(int fd, uint32_t flags, drmDevicePtr *device)
return 0;
#else
- drmDevicePtr *local_devices;
+ drmDevicePtr local_devices[256];
This number is seen later on in this patch, maybe it should be broken out into a
define, since it's reused later on too at [1].
drmDevicePtr d;
DIR *sysdir;
struct dirent *dent;
@@ -3854,7 +3854,6 @@ 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 +3876,9 @@ 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 +3886,6 @@ int drmGetDevice2(int fd, uint32_t flags, drmDevicePtr *device)
if (ret)
continue;
- if (i >= max_count) {
Is this check really not needded what exactly is it that defines 256 as the maximum?
From what I understand readdir(sysdir) is the call that defines how many
devices will be looked through, and as far as I understand it can return an
arbitrary number of files.
- drmDevicePtr *temp;
-
- max_count += 16;
- temp = realloc(local_devices, max_count * sizeof(drmDevicePtr));
- if (!temp)
- goto free_devices;
- local_devices = temp;
- }
-
local_devices[i] = d;
i++;
}
@@ -3921,18 +3904,9 @@ 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 +3942,18 @@ int drmGetDevice(int fd, drmDevicePtr *device)
*/
int drmGetDevices2(uint32_t flags, drmDevicePtr devices[], int max_devices)
{
- drmDevicePtr *local_devices;
+ drmDevicePtr local_devices[256];'
[1]
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 +3961,6 @@ int drmGetDevices2(uint32_t flags, drmDevicePtr devices[], int max_devices)
if (ret)
continue;
- if (i >= max_count) {
This out of bounds check should be dealt with too, if the above bounds check
should be.
- drmDevicePtr *temp;
-
- max_count += 16;
- temp = realloc(local_devices, max_count * sizeof(drmDevicePtr));
- if (!temp)
- goto free_devices;
- local_devices = temp;
- }
-
local_devices[i] = device;
i++;
}
@@ -4025,16 +3982,7 @@ 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;
}
/**
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