[bug report] habanalabs: Timestamps buffers registration

[Dan Carpenter]

Hello farah kassabri,

The patch 9158bf69e74f: "habanalabs: Timestamps buffers registration"
from Dec 23, 2021, leads to the following Smatch static checker
warning:

	drivers/accel/habanalabs/common/memory.c:2178 hl_ts_alloc_buf()
	warn: use 'gfp' here instead of GFP_XXX?

drivers/accel/habanalabs/common/memory.c
    2170 static int hl_ts_alloc_buf(struct hl_mmap_mem_buf *buf, gfp_t gfp, void *args)
                                                                       ^^^
"gfp" is never used.

    2171 {
    2172         struct hl_ts_buff *ts_buff = NULL;
    2173         u32 size, num_elements;
    2174         void *p;
    2175 
    2176         num_elements = *(u32 *)args;

This business of passing void pointers and pretending that
hl_cb_mmap_mem_alloc() and hl_ts_alloc_buf() are the same function is
a nightmare.

Create two ->alloc functions.  Split hl_mmap_mem_buf_alloc() into one
function that allocates idr stuff.  Create a function to free/remove the
idr stuff.  Create two new helper function that call the idr function
and then the appropriate alloc() function.

It will be much cleaner than using a void pointer.

    2177 
--> 2178         ts_buff = kzalloc(sizeof(*ts_buff), GFP_KERNEL);
                                                     ^^^^^^^^^^
Smatch is correct that it should be used here.

    2179         if (!ts_buff)
    2180                 return -ENOMEM;
    2181 
    2182         /* Allocate the user buffer */
    2183         size = num_elements * sizeof(u64);

Can this have an integer overflow on 32bit systems?

    2184         p = vmalloc_user(size);
    2185         if (!p)
    2186                 goto free_mem;
    2187 
    2188         ts_buff->user_buff_address = p;
    2189         buf->mappable_size = size;
    2190 
    2191         /* Allocate the internal kernel buffer */
    2192         size = num_elements * sizeof(struct hl_user_pending_interrupt);
    2193         p = vzalloc(size);
    2194         if (!p)
    2195                 goto free_user_buff;
    2196 
    2197         ts_buff->kernel_buff_address = p;
    2198         ts_buff->kernel_buff_size = size;
    2199 
    2200         buf->private = ts_buff;
    2201 
    2202         return 0;
    2203 
    2204 free_user_buff:
    2205         vfree(ts_buff->user_buff_address);
    2206 free_mem:
    2207         kfree(ts_buff);
    2208         return -ENOMEM;
    2209 }

regards,
dan carpenter