usb_get_configuration() uses a temporary buffer allocated on heap
to read USB configuration descriptor. The buffer is just nine
bytes an so it is a waste to allocate it on heap where it can be
allocated on stack with the rest of local variables. This
simplifies the code and minimises memory usage.
Signed-off-by: Michal Nazarewicz <mina86@xxxxxxxxxx>
---
drivers/usb/core/config.c | 16 ++++------------
1 files changed, 4 insertions(+), 12 deletions(-)
diff --git a/drivers/usb/core/config.c b/drivers/usb/core/config.c
index 0d3af6a..78d3f87 100644
--- a/drivers/usb/core/config.c
+++ b/drivers/usb/core/config.c
@@ -722,13 +722,12 @@ int usb_get_configuration(struct usb_device *dev)
int ncfg = dev->descriptor.bNumConfigurations;
int result = 0;
unsigned int cfgno, length;
- unsigned char *buffer;
unsigned char *bigbuffer;
- struct usb_config_descriptor *desc;
+ struct usb_config_descriptor desc;
cfgno = 0;
if (dev->authorized == 0) /* Not really an error */
- goto out_not_authorized;
+ goto err;
result = -ENOMEM;
if (ncfg > USB_MAXCONFIG) {
dev_warn(ddev, "too many configurations: %d, "
@@ -751,17 +750,12 @@ int usb_get_configuration(struct usb_device *dev)
if (!dev->rawdescriptors)
goto err2;
- buffer = kmalloc(USB_DT_CONFIG_SIZE, GFP_KERNEL);
- if (!buffer)
- goto err2;
- desc = (struct usb_config_descriptor *)buffer;
-
result = 0;
for (; cfgno < ncfg; cfgno++) {
/* We grab just the first descriptor so we know how long
* the whole configuration is */
result = usb_get_descriptor(dev, USB_DT_CONFIG, cfgno,
- buffer, USB_DT_CONFIG_SIZE);
+ &desc, USB_DT_CONFIG_SIZE);
if (result < 0) {
dev_err(ddev, "unable to read config index %d "
"descriptor/%s: %d\n", cfgno, "start", result);
@@ -775,7 +769,7 @@ int usb_get_configuration(struct usb_device *dev)
result = -EINVAL;
goto err;
}
- length = max((int) le16_to_cpu(desc->wTotalLength),
+ length = max((int) le16_to_cpu(desc.wTotalLength),
USB_DT_CONFIG_SIZE);
/* Now that we know the length, get the whole thing */
@@ -810,8 +804,6 @@ int usb_get_configuration(struct usb_device *dev)
result = 0;
err:
- kfree(buffer);
-out_not_authorized:
dev->descriptor.bNumConfigurations = cfgno;
err2:
if (result == -ENOMEM)
--
Best regards, _ _
.o. | Liege of Serenly Enlightened Majesty of o' \,=./ `o
..o | Computer Science, Michal "mina86" Nazarewicz (o o)
ooo +--<mina86-tlen.pl>--<jid:mina86-jabber.org>--ooO--(_)--Ooo--
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