Refactor FastRPC mmap and munmap handling by introducing dedicated
helper functions for DSP-side operations. This change improves code
readability and separates DSP invocation logic from buffer allocation
and cleanup.

Signed-off-by: Ekansh Gupta <ekansh.gupta@oss.qualcomm.com>
---
 drivers/misc/fastrpc.c | 110 +++++++++++++++++++++++++++--------------
 1 file changed, 74 insertions(+), 36 deletions(-)

diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
index ee652ef01534..9bf76e224852 100644
--- a/drivers/misc/fastrpc.c
+++ b/drivers/misc/fastrpc.c
@@ -1811,24 +1811,33 @@ static int fastrpc_get_dsp_info(struct fastrpc_user *fl, char __user *argp)
 	return 0;
 }
 
-static int fastrpc_req_munmap_impl(struct fastrpc_user *fl, struct fastrpc_buf *buf)
+static int fastrpc_req_munmap_dsp(struct fastrpc_user *fl, u64 raddr, u64 size)
 {
 	struct fastrpc_invoke_args args[1] = { [0] = { 0 } };
 	struct fastrpc_munmap_req_msg req_msg;
-	struct device *dev = fl->sctx->dev;
 	int err;
 	u32 sc;
 
 	req_msg.client_id = fl->client_id;
-	req_msg.size = buf->size;
-	req_msg.vaddr = buf->raddr;
+	req_msg.size = size;
+	req_msg.vaddr = raddr;
 
-	args[0].ptr = (u64) (uintptr_t) &req_msg;
+	args[0].ptr = (u64) &req_msg;
 	args[0].length = sizeof(req_msg);
 
 	sc = FASTRPC_SCALARS(FASTRPC_RMID_INIT_MUNMAP, 1, 0);
 	err = fastrpc_internal_invoke(fl, true, FASTRPC_INIT_HANDLE, sc,
 				      &args[0]);
+
+	return err;
+}
+
+static int fastrpc_req_munmap_impl(struct fastrpc_user *fl, struct fastrpc_buf *buf)
+{
+	struct device *dev = fl->sctx->dev;
+	int err;
+
+	err = fastrpc_req_munmap_dsp(fl, buf->raddr, buf->size);
 	if (!err) {
 		dev_dbg(dev, "unmmap\tpt 0x%09lx OK\n", buf->raddr);
 		spin_lock(&fl->lock);
@@ -1869,26 +1878,54 @@ static int fastrpc_req_munmap(struct fastrpc_user *fl, char __user *argp)
 	return fastrpc_req_munmap_impl(fl, buf);
 }
 
-static int fastrpc_req_mmap(struct fastrpc_user *fl, char __user *argp)
+static int fastrpc_req_map_dsp(struct fastrpc_user *fl, u64 phys,
+			       u64 size, u32 flag, u64 vaddrin,
+			       u64 *raddr)
 {
 	struct fastrpc_invoke_args args[3] = { [0 ... 2] = { 0 } };
-	struct fastrpc_buf *buf = NULL;
 	struct fastrpc_mmap_req_msg req_msg;
 	struct fastrpc_mmap_rsp_msg rsp_msg;
 	struct fastrpc_phy_page pages;
-	struct fastrpc_req_mmap req;
-	struct device *dev = fl->sctx->dev;
 	int err;
 	u32 sc;
 
-	if (copy_from_user(&req, argp, sizeof(req)))
-		return -EFAULT;
+	req_msg.client_id = fl->client_id;
+	req_msg.flags = flag;
+	req_msg.vaddr = vaddrin;
+	req_msg.num = sizeof(pages);
 
-	if (req.flags != ADSP_MMAP_ADD_PAGES && req.flags != ADSP_MMAP_REMOTE_HEAP_ADDR) {
-		dev_err(dev, "flag not supported 0x%x\n", req.flags);
+	args[0].ptr = (u64)&req_msg;
+	args[0].length = sizeof(req_msg);
 
-		return -EINVAL;
+	pages.addr = phys;
+	pages.size = size;
+
+	args[1].ptr = (u64)&pages;
+	args[1].length = sizeof(pages);
+
+	args[2].ptr = (u64)&rsp_msg;
+	args[2].length = sizeof(rsp_msg);
+	sc = FASTRPC_SCALARS(FASTRPC_RMID_INIT_MMAP, 2, 1);
+	err = fastrpc_internal_invoke(fl, true, FASTRPC_INIT_HANDLE, sc,
+				      &args[0]);
+
+	if (err) {
+		dev_err(fl->sctx->dev, "mmap error (len 0x%08llx)\n", size);
+		return err;
 	}
+	*raddr = rsp_msg.vaddr;
+
+	return 0;
+}
+
+static int fastrpc_req_buf_alloc(struct fastrpc_user *fl,
+				 struct fastrpc_req_mmap req,
+				 char __user *argp)
+{
+	struct device *dev = fl->sctx->dev;
+	struct fastrpc_buf *buf = NULL;
+	u64 raddr = 0;
+	int err;
 
 	if (req.vaddrin) {
 		dev_err(dev, "adding user allocated pages is not supported\n");
@@ -1905,26 +1942,8 @@ static int fastrpc_req_mmap(struct fastrpc_user *fl, char __user *argp)
 		return err;
 	}
 
-	req_msg.client_id = fl->client_id;
-	req_msg.flags = req.flags;
-	req_msg.vaddr = req.vaddrin;
-	req_msg.num = sizeof(pages);
-
-	args[0].ptr = (u64) (uintptr_t) &req_msg;
-	args[0].length = sizeof(req_msg);
-
-	pages.addr = buf->phys;
-	pages.size = buf->size;
-
-	args[1].ptr = (u64) (uintptr_t) &pages;
-	args[1].length = sizeof(pages);
-
-	args[2].ptr = (u64) (uintptr_t) &rsp_msg;
-	args[2].length = sizeof(rsp_msg);
-
-	sc = FASTRPC_SCALARS(FASTRPC_RMID_INIT_MMAP, 2, 1);
-	err = fastrpc_internal_invoke(fl, true, FASTRPC_INIT_HANDLE, sc,
-				      &args[0]);
+	err = fastrpc_req_map_dsp(fl, buf->phys, buf->size, req.flags,
+				  req.vaddrin, &raddr);
 	if (err) {
 		dev_err(dev, "mmap error (len 0x%08llx)\n", buf->size);
 		fastrpc_buf_free(buf);
@@ -1932,10 +1951,10 @@ static int fastrpc_req_mmap(struct fastrpc_user *fl, char __user *argp)
 	}
 
 	/* update the buffer to be able to deallocate the memory on the DSP */
-	buf->raddr = (uintptr_t) rsp_msg.vaddr;
+	buf->raddr = (uintptr_t)raddr;
 
 	/* let the client know the address to use */
-	req.vaddrout = rsp_msg.vaddr;
+	req.vaddrout = raddr;
 
 	/* Add memory to static PD pool, protection thru hypervisor */
 	if (req.flags == ADSP_MMAP_REMOTE_HEAP_ADDR && fl->cctx->vmcount) {
@@ -1970,6 +1989,25 @@ static int fastrpc_req_mmap(struct fastrpc_user *fl, char __user *argp)
 	return err;
 }
 
+static int fastrpc_req_mmap(struct fastrpc_user *fl, char __user *argp)
+{
+	struct fastrpc_req_mmap req;
+	int err;
+
+	if (copy_from_user(&req, argp, sizeof(req)))
+		return -EFAULT;
+
+	if (req.flags != ADSP_MMAP_ADD_PAGES && req.flags != ADSP_MMAP_REMOTE_HEAP_ADDR) {
+		dev_err(fl->sctx->dev, "flag not supported 0x%x\n", req.flags);
+
+		return -EINVAL;
+	}
+
+	err = fastrpc_req_buf_alloc(fl, req, argp);
+
+	return err;
+}
+
 static int fastrpc_req_mem_unmap_impl(struct fastrpc_user *fl, struct fastrpc_mem_unmap *req)
 {
 	struct fastrpc_invoke_args args[1] = { [0] = { 0 } };
-- 
2.34.1

Hi Ekansh,

kernel test robot noticed the following build warnings:

[auto build test WARNING on char-misc/char-misc-testing]
[also build test WARNING on char-misc/char-misc-next char-misc/char-misc-linus linus/master v6.18-rc7 next-20251128]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Ekansh-Gupta/misc-fastrpc-Refactor-mmap-and-munmap-logic-into-helper-functions/20251128-183620
base:   char-misc/char-misc-testing
patch link:    https://lore.kernel.org/r/20251128103428.1119696-2-ekansh.gupta%40oss.qualcomm.com
patch subject: [PATCH v2 1/2] misc: fastrpc: Refactor mmap and munmap logic into helper functions
config: arm-allyesconfig (https://download.01.org/0day-ci/archive/20251129/202511291834.zu81Ud77-lkp@intel.com/config)
compiler: arm-linux-gnueabi-gcc (GCC) 15.1.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251129/202511291834.zu81Ud77-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202511291834.zu81Ud77-lkp@intel.com/

All warnings (new ones prefixed by >>):

   drivers/misc/fastrpc.c: In function 'fastrpc_req_munmap_dsp':
>> drivers/misc/fastrpc.c:1825:23: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
    1825 |         args[0].ptr = (u64) &req_msg;
         |                       ^
   drivers/misc/fastrpc.c: In function 'fastrpc_req_map_dsp':
   drivers/misc/fastrpc.c:1897:23: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
    1897 |         args[0].ptr = (u64)&req_msg;
         |                       ^
   drivers/misc/fastrpc.c:1903:23: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
    1903 |         args[1].ptr = (u64)&pages;
         |                       ^
   drivers/misc/fastrpc.c:1906:23: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
    1906 |         args[2].ptr = (u64)&rsp_msg;
         |                       ^


vim +1825 drivers/misc/fastrpc.c

  1813	
  1814	static int fastrpc_req_munmap_dsp(struct fastrpc_user *fl, u64 raddr, u64 size)
  1815	{
  1816		struct fastrpc_invoke_args args[1] = { [0] = { 0 } };
  1817		struct fastrpc_munmap_req_msg req_msg;
  1818		int err;
  1819		u32 sc;
  1820	
  1821		req_msg.client_id = fl->client_id;
  1822		req_msg.size = size;
  1823		req_msg.vaddr = raddr;
  1824	
> 1825		args[0].ptr = (u64) &req_msg;
  1826		args[0].length = sizeof(req_msg);
  1827	
  1828		sc = FASTRPC_SCALARS(FASTRPC_RMID_INIT_MUNMAP, 1, 0);
  1829		err = fastrpc_internal_invoke(fl, true, FASTRPC_INIT_HANDLE, sc,
  1830					      &args[0]);
  1831	
  1832		return err;
  1833	}
  1834	

-- 
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https://github.com/intel/lkp-tests/wiki