The code below is in user-space and that MACRO(__vpa) is in
kernel-space.
/* MALLOC_REQ
Structure used on allocation requests to the driver.
Used by KernelMalloc() & KernelFree()
*/
typedef struct{
unsigned long sz; /*number of bytes to allocate*/
void *ptr; /* pointer to the address that is to ve returned */
char *to;
char *from;
int pid; /*pid */
}MALLOC_REQ;
MALLOC_REQ kmem;
Ioctl(fd, IOCTL_MALLOC, &kmem);
.....
.....
Ioctl(fd,IOCTL_FREE,*block);
Can provide you more details.
Thanks
-vikas
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-----Original Message-----
From: Thomas Petazzoni [mailto:thomas.petazzoni@xxxxxxxx]
Sent: Tuesday, July 26, 2005 10:51 AM
To: Aggarwal, Vikas (OFT)
Cc: kernelnewbies@xxxxxxxxxxxx
Subject: Re: porting a mm specific macro from 2.4 to 2.6
Hello,
Aggarwal, Vikas (OFT) wrote:
> Here is the context-of-use --
> The driver is for Crypto-Hardware-Accelerator(CHA). The user space
> creates the Descriptors(which has data to be encrypted, type of
> crypto-algorithm etc) which guides the CHA.
> A dummy malloc is implemented in kernel driver which uses kmalloc and
> user can request that memory(to create Descriptors) via
> IOCTL(CHA_MALLOC). The idea is (most likely) to avoid the "copy from
> usersapce". Then the descriptor pointer is filled with the data by
> user-space which passes it back to CHA via second
> IOCTL(CHA_CRYPT_REQUEST).
I am sorry, I don't know how CHA works, so I may ask stupid questions.
You say that your IOCTL(CHA_MALLOC) allocates memory in kernel-space
using kmalloc() and returns that address to the user-space. Then you say
the "user can request that memory". What do you mean by "request" ? How
does the user-space accesses this kernel-allocated memory ?
Once I'll clearly understand how it works, I'll try to give an answer
about the initial problem.
Sincerly,
Thomas
--
Thomas Petazzoni
thomas.petazzoni@xxxxxxxx
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