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media: atomisp: fix -Wdangling-pointer warning

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ia_css_rmgr_acq_vbuf() uses a local on stack
"struct ia_css_rmgr_vbuf_handle v" variable.

When this path using this is hit, either the rmgr_pop_handle() call
will make *handle point to another vbuf-handle, or because
v.count == 0, ia_css_rmgr_refcount_retain_vbuf() will alloc a new
vbuf-handle and make *handle point to it.

So on leaving the function *handle will never point to the on stack
vbuf-handle, but gcc does not know this and emits the following:

drivers/staging/media/atomisp/pci/runtime/rmgr/src/rmgr_vbuf.c: In function ‘ia_css_rmgr_acq_vbuf’:
drivers/staging/media/atomisp/pci/runtime/rmgr/src/rmgr_vbuf.c:276:33: warning: storing the address of local variable ‘h’ in ‘*handle’ [-Wdangling-pointer=]
  276 |                         *handle = &h;
      |                         ~~~~~~~~^~~~
drivers/staging/media/atomisp/pci/runtime/rmgr/src/rmgr_vbuf.c:257:40: note: ‘h’ declared here
  257 |         struct ia_css_rmgr_vbuf_handle h;
      |                                        ^
drivers/staging/media/atomisp/pci/runtime/rmgr/src/rmgr_vbuf.c:257:40: note: ‘handle’ declared here

Rework the code using a new_handle helper to suppress this
false-postive compiler warning.

Link: https://lore.kernel.org/linux-media/20220612160556.108264-4-hdegoede@redhat.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
This commit is contained in:
Hans de Goede 2022-06-12 17:05:56 +01:00 committed by Mauro Carvalho Chehab
parent 42ec2f0714
commit 1713dceb57
1 changed files with 15 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
drivers/staging/media/atomisp/pci/runtime/rmgr/src/rmgr_vbuf.c
View File

@ -254,14 +254,15 @@ void rmgr_pop_handle(struct ia_css_rmgr_vbuf_pool *pool,
void ia_css_rmgr_acq_vbuf(struct ia_css_rmgr_vbuf_pool *pool,
struct ia_css_rmgr_vbuf_handle **handle)
{
struct ia_css_rmgr_vbuf_handle h = { 0 };
if ((!pool) || (!handle) || (!*handle)) {
IA_CSS_LOG("Invalid inputs");
return;
}
if (pool->copy_on_write) {
struct ia_css_rmgr_vbuf_handle *new_handle;
struct ia_css_rmgr_vbuf_handle h = { 0 };
/* only one reference, reuse (no new retain) */
if ((*handle)->count == 1)
return;
@ -272,22 +273,29 @@ void ia_css_rmgr_acq_vbuf(struct ia_css_rmgr_vbuf_pool *pool,
h.size = (*handle)->size;
/* release ref to current buffer */
ia_css_rmgr_refcount_release_vbuf(handle);
*handle = &h;
new_handle = &h;
} else {
new_handle = *handle;
}
/* get new buffer for needed size */
if ((*handle)->vptr == 0x0) {
if (new_handle->vptr == 0x0) {
if (pool->recycle) {
/* try and pop from pool */
rmgr_pop_handle(pool, handle);
rmgr_pop_handle(pool, &new_handle);
}
if ((*handle)->vptr == 0x0) {
if (new_handle->vptr == 0x0) {
/* we need to allocate */
(*handle)->vptr = hmm_alloc((*handle)->size);
new_handle->vptr = hmm_alloc(new_handle->size);
} else {
/* we popped a buffer */
*handle = new_handle;
return;
}
}
/* Note that new_handle will change to an internally maintained one */
ia_css_rmgr_refcount_retain_vbuf(&new_handle);
*handle = new_handle;
return;
}
/* Note that handle will change to an internally maintained one */
ia_css_rmgr_refcount_retain_vbuf(handle);