linux-kernel - Re: [Linux-fbdev-devel] [PATCH 3/3] drivers/video: Correct use of request_region/request_mem

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Date:	Sun, 9 Aug 2009 11:42:32 +0200 (CEST)
From:	Julia Lawall <julia@...u.dk>
To:	Geert Uytterhoeven <geert.uytterhoeven@...il.com>
Cc:	linux-fbdev-devel@...ts.sourceforge.net,
	linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org,
	linux-mips@...ux-mips.org
Subject: Re: [Linux-fbdev-devel] [PATCH 3/3] drivers/video: Correct use of 
 request_region/request_mem_region

From: Julia Lawall <julia@...u.dk>

request_region should be used with release_region, not request_mem_region.

Geert Uytterhoeven pointed out that in the case of drivers/video/gbefb.c,
the problem is actually the other way around; request_mem_region should be
used instead of request_region.

The semantic patch that finds/fixes this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@r1@
expression start;
@@

request_region(start,...)

@b1@
expression r1.start;
@@

request_mem_region(start,...)

@depends on !b1@
expression r1.start;
expression E;
@@

- release_mem_region
+ release_region
  (start,E)
// </smpl>

Signed-off-by: Julia Lawall <julia@...u.dk>

---
 drivers/video/gbefb.c  |    2 +-
 drivers/video/tdfxfb.c |    4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff -u -p a/drivers/video/gbefb.c b/drivers/video/gbefb.c
--- a/drivers/video/gbefb.c
+++ b/drivers/video/gbefb.c
@@ -1147,7 +1147,7 @@ static int __init gbefb_probe(struct pla
 	gbefb_setup(options);
 #endif
 
-	if (!request_region(GBE_BASE, sizeof(struct sgi_gbe), "GBE")) {
+	if (!request_mem_region(GBE_BASE, sizeof(struct sgi_gbe), "GBE")) {
 		printk(KERN_ERR "gbefb: couldn't reserve mmio region\n");
 		ret = -EBUSY;
 		goto out_release_framebuffer;
diff -u -p a/drivers/video/tdfxfb.c b/drivers/video/tdfxfb.c
--- a/drivers/video/tdfxfb.c
+++ b/drivers/video/tdfxfb.c
@@ -1571,8 +1571,8 @@ out_err_iobase:
 	if (default_par->mtrr_handle >= 0)
 		mtrr_del(default_par->mtrr_handle, info->fix.smem_start,
 			 info->fix.smem_len);
-	release_mem_region(pci_resource_start(pdev, 2),
-			   pci_resource_len(pdev, 2));
+	release_region(pci_resource_start(pdev, 2),
+		       pci_resource_len(pdev, 2));
 out_err_screenbase:
 	if (info->screen_base)
 		iounmap(info->screen_base);
--
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