linux-kernel - [PATCH v2] media: atomisp: Fixed error handling path

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Date:   Wed,  4 Nov 2020 07:32:11 +0530
From:   Souptick Joarder <jrdr.linux@...il.com>
To:     mchehab@...nel.org, sakari.ailus@...ux.intel.com,
        gregkh@...uxfoundation.org, gustavoars@...nel.org,
        akpm@...ux-foundation.org, vbabka@...e.cz,
        daniel.m.jordan@...cle.com, walken@...gle.com
Cc:     linux-media@...r.kernel.org, devel@...verdev.osuosl.org,
        linux-kernel@...r.kernel.org,
        Souptick Joarder <jrdr.linux@...il.com>,
        John Hubbard <jhubbard@...dia.com>,
        Ira Weiny <ira.weiny@...el.com>,
        Dan Carpenter <dan.carpenter@...cle.com>
Subject: [PATCH v2] media: atomisp: Fixed error handling path

Inside alloc_user_pages() based on flag value either pin_user_pages()
or get_user_pages_fast() will be called. However, these API might fail.

But free_user_pages() called in error handling path doesn't bother
about return value and will try to unpin bo->pgnr pages, which is
incorrect.

Fix this by passing the page_nr to free_user_pages(). If page_nr > 0
pages will be unpinned based on bo->mem_type. This will also take care
of non error handling path.

Fixes: 14a638ab96c5 ("media: atomisp: use pin_user_pages() for memory
allocation")
Signed-off-by: Souptick Joarder <jrdr.linux@...il.com>
Reviewed-by: Dan Carpenter <dan.carpenter@...cle.com>
Cc: John Hubbard <jhubbard@...dia.com>
Cc: Ira Weiny <ira.weiny@...el.com>
Cc: Dan Carpenter <dan.carpenter@...cle.com>
---
v2:
    Added review tag.

 drivers/staging/media/atomisp/pci/hmm/hmm_bo.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/drivers/staging/media/atomisp/pci/hmm/hmm_bo.c b/drivers/staging/media/atomisp/pci/hmm/hmm_bo.c
index f13af23..0168f98 100644
--- a/drivers/staging/media/atomisp/pci/hmm/hmm_bo.c
+++ b/drivers/staging/media/atomisp/pci/hmm/hmm_bo.c
@@ -857,16 +857,17 @@ static void free_private_pages(struct hmm_buffer_object *bo,
 	kfree(bo->page_obj);
 }
 
-static void free_user_pages(struct hmm_buffer_object *bo)
+static void free_user_pages(struct hmm_buffer_object *bo,
+			    unsigned int page_nr)
 {
 	int i;
 
 	hmm_mem_stat.usr_size -= bo->pgnr;
 
 	if (bo->mem_type == HMM_BO_MEM_TYPE_PFN) {
-		unpin_user_pages(bo->pages, bo->pgnr);
+		unpin_user_pages(bo->pages, page_nr);
 	} else {
-		for (i = 0; i < bo->pgnr; i++)
+		for (i = 0; i < page_nr; i++)
 			put_page(bo->pages[i]);
 	}
 	kfree(bo->pages);
@@ -942,6 +943,8 @@ static int alloc_user_pages(struct hmm_buffer_object *bo,
 		dev_err(atomisp_dev,
 			"get_user_pages err: bo->pgnr = %d, pgnr actually pinned = %d.\n",
 			bo->pgnr, page_nr);
+		if (page_nr < 0)
+			page_nr = 0;
 		goto out_of_mem;
 	}
 
@@ -954,7 +957,7 @@ static int alloc_user_pages(struct hmm_buffer_object *bo,
 
 out_of_mem:
 
-	free_user_pages(bo);
+	free_user_pages(bo, page_nr);
 
 	return -ENOMEM;
 }
@@ -1037,7 +1040,7 @@ void hmm_bo_free_pages(struct hmm_buffer_object *bo)
 	if (bo->type == HMM_BO_PRIVATE)
 		free_private_pages(bo, &dynamic_pool, &reserved_pool);
 	else if (bo->type == HMM_BO_USER)
-		free_user_pages(bo);
+		free_user_pages(bo, bo->pgnr);
 	else
 		dev_err(atomisp_dev, "invalid buffer type.\n");
 	mutex_unlock(&bo->mutex);
-- 
1.9.1