Staging: winbond: Check for unsuccessful allocation immediately

Check to see if allocation by kzalloc() or usb_alloc_urb() was unsuccessful
immediately after the allocation. Exit from the function can be right at that
point in case of allocation failure.
This avoids unnecessary use of usb_alloc_urb() & usb_free_urb() if kzalloc()
returns NULL.
Also, makes the code better structured & easier to understand.

Signed-off-by: Harsh Kumar <harsh1kumar@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/winbond/wb35reg.c b/drivers/staging/winbond/wb35reg.c
index 0194204..9be1b3b 100644 (file)
--- a/drivers/staging/winbond/wb35reg.c
+++ b/drivers/staging/winbond/wb35reg.c
@@ -30,45 +30,46 @@ unsigned char Wb35Reg_BurstWrite(struct hw_data *pHwData, u16 RegisterNo, u32 *p
        /* Trying to use burst write function if use new hardware */
        UrbSize = sizeof(struct wb35_reg_queue) + DataSize + sizeof(struct usb_ctrlrequest);
        reg_queue = kzalloc(UrbSize, GFP_ATOMIC);
+       if (reg_queue == NULL)
+               return false;
+
        urb = usb_alloc_urb(0, GFP_ATOMIC);
-       if (urb && reg_queue) {
-               reg_queue->DIRECT = 2; /* burst write register */
-               reg_queue->INDEX = RegisterNo;
-               reg_queue->pBuffer = (u32 *)((u8 *)reg_queue + sizeof(struct wb35_reg_queue));
-               memcpy(reg_queue->pBuffer, pRegisterData, DataSize);
-               /* the function for reversing register data from little endian to big endian */
-               for (i = 0; i < NumberOfData ; i++)
-                       reg_queue->pBuffer[i] = cpu_to_le32(reg_queue->pBuffer[i]);
-
-               dr = (struct usb_ctrlrequest *)((u8 *)reg_queue + sizeof(struct wb35_reg_queue) + DataSize);
-               dr->bRequestType = USB_TYPE_VENDOR | USB_DIR_OUT | USB_RECIP_DEVICE;
-               dr->bRequest = 0x04; /* USB or vendor-defined request code, burst mode */
-               dr->wValue = cpu_to_le16(Flag); /* 0: Register number auto-increment, 1: No auto increment */
-               dr->wIndex = cpu_to_le16(RegisterNo);
-               dr->wLength = cpu_to_le16(DataSize);
-               reg_queue->Next = NULL;
-               reg_queue->pUsbReq = dr;
-               reg_queue->urb = urb;
+       if (urb == NULL) {
+               kfree(reg_queue);
+               return false;
+       }
 
-               spin_lock_irq(&reg->EP0VM_spin_lock);
-               if (reg->reg_first == NULL)
-                       reg->reg_first = reg_queue;
-               else
-                       reg->reg_last->Next = reg_queue;
-               reg->reg_last = reg_queue;
+       reg_queue->DIRECT = 2; /* burst write register */
+       reg_queue->INDEX = RegisterNo;
+       reg_queue->pBuffer = (u32 *)((u8 *)reg_queue + sizeof(struct wb35_reg_queue));
+       memcpy(reg_queue->pBuffer, pRegisterData, DataSize);
+       /* the function for reversing register data from little endian to big endian */
+       for (i = 0; i < NumberOfData ; i++)
+               reg_queue->pBuffer[i] = cpu_to_le32(reg_queue->pBuffer[i]);
+
+       dr = (struct usb_ctrlrequest *)((u8 *)reg_queue + sizeof(struct wb35_reg_queue) + DataSize);
+       dr->bRequestType = USB_TYPE_VENDOR | USB_DIR_OUT | USB_RECIP_DEVICE;
+       dr->bRequest = 0x04; /* USB or vendor-defined request code, burst mode */
+       dr->wValue = cpu_to_le16(Flag); /* 0: Register number auto-increment, 1: No auto increment */
+       dr->wIndex = cpu_to_le16(RegisterNo);
+       dr->wLength = cpu_to_le16(DataSize);
+       reg_queue->Next = NULL;
+       reg_queue->pUsbReq = dr;
+       reg_queue->urb = urb;
 
-               spin_unlock_irq(&reg->EP0VM_spin_lock);
+       spin_lock_irq(&reg->EP0VM_spin_lock);
+       if (reg->reg_first == NULL)
+               reg->reg_first = reg_queue;
+       else
+               reg->reg_last->Next = reg_queue;
+       reg->reg_last = reg_queue;
 
-               /* Start EP0VM */
-               Wb35Reg_EP0VM_start(pHwData);
+       spin_unlock_irq(&reg->EP0VM_spin_lock);
 
-               return true;
-       } else {
-               usb_free_urb(urb);
-               kfree(reg_queue);
-               return false;
-       }
-       return false;
+       /* Start EP0VM */
+       Wb35Reg_EP0VM_start(pHwData);
+
+       return true;
 }
 
 void Wb35Reg_Update(struct hw_data *pHwData,  u16 RegisterNo,  u32 RegisterValue)
@@ -173,42 +174,44 @@ unsigned char Wb35Reg_Write(struct hw_data *pHwData, u16 RegisterNo, u32 Registe
        /* update the register by send urb request */
        UrbSize = sizeof(struct wb35_reg_queue) + sizeof(struct usb_ctrlrequest);
        reg_queue = kzalloc(UrbSize, GFP_ATOMIC);
+       if (reg_queue == NULL)
+               return false;
+
        urb = usb_alloc_urb(0, GFP_ATOMIC);
-       if (urb && reg_queue) {
-               reg_queue->DIRECT = 1; /* burst write register */
-               reg_queue->INDEX = RegisterNo;
-               reg_queue->VALUE = cpu_to_le32(RegisterValue);
-               reg_queue->RESERVED_VALID = false;
-               dr = (struct usb_ctrlrequest *)((u8 *)reg_queue + sizeof(struct wb35_reg_queue));
-               dr->bRequestType = USB_TYPE_VENDOR | USB_DIR_OUT | USB_RECIP_DEVICE;
-               dr->bRequest = 0x03; /* USB or vendor-defined request code, burst mode */
-               dr->wValue = cpu_to_le16(0x0);
-               dr->wIndex = cpu_to_le16(RegisterNo);
-               dr->wLength = cpu_to_le16(4);
-
-               /* Enter the sending queue */
-               reg_queue->Next = NULL;
-               reg_queue->pUsbReq = dr;
-               reg_queue->urb = urb;
+       if (urb == NULL) {
+               kfree(reg_queue);
+               return false;
+       }
 
-               spin_lock_irq(&reg->EP0VM_spin_lock);
-               if (reg->reg_first == NULL)
-                       reg->reg_first = reg_queue;
-               else
-                       reg->reg_last->Next = reg_queue;
-               reg->reg_last = reg_queue;
+       reg_queue->DIRECT = 1; /* burst write register */
+       reg_queue->INDEX = RegisterNo;
+       reg_queue->VALUE = cpu_to_le32(RegisterValue);
+       reg_queue->RESERVED_VALID = false;
+       dr = (struct usb_ctrlrequest *)((u8 *)reg_queue + sizeof(struct wb35_reg_queue));
+       dr->bRequestType = USB_TYPE_VENDOR | USB_DIR_OUT | USB_RECIP_DEVICE;
+       dr->bRequest = 0x03; /* USB or vendor-defined request code, burst mode */
+       dr->wValue = cpu_to_le16(0x0);
+       dr->wIndex = cpu_to_le16(RegisterNo);
+       dr->wLength = cpu_to_le16(4);
+
+       /* Enter the sending queue */
+       reg_queue->Next = NULL;
+       reg_queue->pUsbReq = dr;
+       reg_queue->urb = urb;
 
-               spin_unlock_irq(&reg->EP0VM_spin_lock);
+       spin_lock_irq(&reg->EP0VM_spin_lock);
+       if (reg->reg_first == NULL)
+               reg->reg_first = reg_queue;
+       else
+               reg->reg_last->Next = reg_queue;
+       reg->reg_last = reg_queue;
 
-               /* Start EP0VM */
-               Wb35Reg_EP0VM_start(pHwData);
+       spin_unlock_irq(&reg->EP0VM_spin_lock);
 
-               return true;
-       } else {
-               usb_free_urb(urb);
-               kfree(reg_queue);
-               return false;
-       }
+       /* Start EP0VM */
+       Wb35Reg_EP0VM_start(pHwData);
+
+       return true;
 }
 
 /*
@@ -236,42 +239,45 @@ unsigned char Wb35Reg_WriteWithCallbackValue(struct hw_data *pHwData,
        /* update the register by send urb request */
        UrbSize = sizeof(struct wb35_reg_queue) + sizeof(struct usb_ctrlrequest);
        reg_queue = kzalloc(UrbSize, GFP_ATOMIC);
-       urb = usb_alloc_urb(0, GFP_ATOMIC);
-       if (urb && reg_queue) {
-               reg_queue->DIRECT = 1; /* burst write register */
-               reg_queue->INDEX = RegisterNo;
-               reg_queue->VALUE = cpu_to_le32(RegisterValue);
-               /* NOTE : Users must guarantee the size of value will not exceed the buffer size. */
-               memcpy(reg_queue->RESERVED, pValue, Len);
-               reg_queue->RESERVED_VALID = true;
-               dr = (struct usb_ctrlrequest *)((u8 *)reg_queue + sizeof(struct wb35_reg_queue));
-               dr->bRequestType = USB_TYPE_VENDOR | USB_DIR_OUT | USB_RECIP_DEVICE;
-               dr->bRequest = 0x03; /* USB or vendor-defined request code, burst mode */
-               dr->wValue = cpu_to_le16(0x0);
-               dr->wIndex = cpu_to_le16(RegisterNo);
-               dr->wLength = cpu_to_le16(4);
-
-               /* Enter the sending queue */
-               reg_queue->Next = NULL;
-               reg_queue->pUsbReq = dr;
-               reg_queue->urb = urb;
-               spin_lock_irq(&reg->EP0VM_spin_lock);
-               if (reg->reg_first == NULL)
-                       reg->reg_first = reg_queue;
-               else
-                       reg->reg_last->Next = reg_queue;
-               reg->reg_last = reg_queue;
-
-               spin_unlock_irq(&reg->EP0VM_spin_lock);
+       if (reg_queue == NULL)
+               return false;
 
-               /* Start EP0VM */
-               Wb35Reg_EP0VM_start(pHwData);
-               return true;
-       } else {
-               usb_free_urb(urb);
+       urb = usb_alloc_urb(0, GFP_ATOMIC);
+       if (urb == NULL) {
                kfree(reg_queue);
                return false;
        }
+
+       reg_queue->DIRECT = 1; /* burst write register */
+       reg_queue->INDEX = RegisterNo;
+       reg_queue->VALUE = cpu_to_le32(RegisterValue);
+       /* NOTE : Users must guarantee the size of value will not exceed the buffer size. */
+       memcpy(reg_queue->RESERVED, pValue, Len);
+       reg_queue->RESERVED_VALID = true;
+       dr = (struct usb_ctrlrequest *)((u8 *)reg_queue + sizeof(struct wb35_reg_queue));
+       dr->bRequestType = USB_TYPE_VENDOR | USB_DIR_OUT | USB_RECIP_DEVICE;
+       dr->bRequest = 0x03; /* USB or vendor-defined request code, burst mode */
+       dr->wValue = cpu_to_le16(0x0);
+       dr->wIndex = cpu_to_le16(RegisterNo);
+       dr->wLength = cpu_to_le16(4);
+
+       /* Enter the sending queue */
+       reg_queue->Next = NULL;
+       reg_queue->pUsbReq = dr;
+       reg_queue->urb = urb;
+       spin_lock_irq(&reg->EP0VM_spin_lock);
+       if (reg->reg_first == NULL)
+               reg->reg_first = reg_queue;
+       else
+               reg->reg_last->Next = reg_queue;
+       reg->reg_last = reg_queue;
+
+       spin_unlock_irq(&reg->EP0VM_spin_lock);
+
+       /* Start EP0VM */
+       Wb35Reg_EP0VM_start(pHwData);
+
+       return true;
 }
 
 /*
@@ -341,40 +347,41 @@ unsigned char Wb35Reg_Read(struct hw_data *pHwData, u16 RegisterNo, u32 *pRegist
        /* update the variable by send Urb to read register */
        UrbSize = sizeof(struct wb35_reg_queue) + sizeof(struct usb_ctrlrequest);
        reg_queue = kzalloc(UrbSize, GFP_ATOMIC);
-       urb = usb_alloc_urb(0, GFP_ATOMIC);
-       if (urb && reg_queue) {
-               reg_queue->DIRECT = 0; /* read register */
-               reg_queue->INDEX = RegisterNo;
-               reg_queue->pBuffer = pRegisterValue;
-               dr = (struct usb_ctrlrequest *)((u8 *)reg_queue + sizeof(struct wb35_reg_queue));
-               dr->bRequestType = USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN;
-               dr->bRequest = 0x01; /* USB or vendor-defined request code, burst mode */
-               dr->wValue = cpu_to_le16(0x0);
-               dr->wIndex = cpu_to_le16(RegisterNo);
-               dr->wLength = cpu_to_le16(4);
-
-               /* Enter the sending queue */
-               reg_queue->Next = NULL;
-               reg_queue->pUsbReq = dr;
-               reg_queue->urb = urb;
-               spin_lock_irq(&reg->EP0VM_spin_lock);
-               if (reg->reg_first == NULL)
-                       reg->reg_first = reg_queue;
-               else
-                       reg->reg_last->Next = reg_queue;
-               reg->reg_last = reg_queue;
-
-               spin_unlock_irq(&reg->EP0VM_spin_lock);
-
-               /* Start EP0VM */
-               Wb35Reg_EP0VM_start(pHwData);
+       if (reg_queue == NULL)
+               return false;
 
-               return true;
-       } else {
-               usb_free_urb(urb);
+       urb = usb_alloc_urb(0, GFP_ATOMIC);
+       if (urb == NULL) {
                kfree(reg_queue);
                return false;
        }
+       reg_queue->DIRECT = 0; /* read register */
+       reg_queue->INDEX = RegisterNo;
+       reg_queue->pBuffer = pRegisterValue;
+       dr = (struct usb_ctrlrequest *)((u8 *)reg_queue + sizeof(struct wb35_reg_queue));
+       dr->bRequestType = USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN;
+       dr->bRequest = 0x01; /* USB or vendor-defined request code, burst mode */
+       dr->wValue = cpu_to_le16(0x0);
+       dr->wIndex = cpu_to_le16(RegisterNo);
+       dr->wLength = cpu_to_le16(4);
+
+       /* Enter the sending queue */
+       reg_queue->Next = NULL;
+       reg_queue->pUsbReq = dr;
+       reg_queue->urb = urb;
+       spin_lock_irq(&reg->EP0VM_spin_lock);
+       if (reg->reg_first == NULL)
+               reg->reg_first = reg_queue;
+       else
+               reg->reg_last->Next = reg_queue;
+       reg->reg_last = reg_queue;
+
+       spin_unlock_irq(&reg->EP0VM_spin_lock);
+
+       /* Start EP0VM */
+       Wb35Reg_EP0VM_start(pHwData);
+
+       return true;
 }